WO2024048695A1 - Composite semipermeable membrane and method for producing composite semipermeable membrane - Google Patents
Composite semipermeable membrane and method for producing composite semipermeable membrane Download PDFInfo
- Publication number
- WO2024048695A1 WO2024048695A1 PCT/JP2023/031656 JP2023031656W WO2024048695A1 WO 2024048695 A1 WO2024048695 A1 WO 2024048695A1 JP 2023031656 W JP2023031656 W JP 2023031656W WO 2024048695 A1 WO2024048695 A1 WO 2024048695A1
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- WO
- WIPO (PCT)
- Prior art keywords
- composite semipermeable
- semipermeable membrane
- protrusion
- membrane
- microporous support
- Prior art date
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 217
- 239000002131 composite material Substances 0.000 title claims abstract description 121
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 238000000926 separation method Methods 0.000 claims abstract description 83
- 239000010409 thin film Substances 0.000 claims abstract description 40
- 239000004760 aramid Substances 0.000 claims abstract description 37
- 229920003235 aromatic polyamide Polymers 0.000 claims abstract description 37
- 238000005430 electron energy loss spectroscopy Methods 0.000 claims abstract description 9
- 125000004433 nitrogen atom Chemical group N* 0.000 claims abstract description 7
- 125000004430 oxygen atom Chemical group O* 0.000 claims abstract description 6
- 239000010410 layer Substances 0.000 claims description 84
- 239000002346 layers by function Substances 0.000 claims description 66
- 239000000243 solution Substances 0.000 claims description 50
- 150000004982 aromatic amines Chemical class 0.000 claims description 43
- 238000000034 method Methods 0.000 claims description 39
- 239000007864 aqueous solution Substances 0.000 claims description 33
- -1 aromatic acid halide Chemical class 0.000 claims description 25
- 239000003960 organic solvent Substances 0.000 claims description 23
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- WZCQRUWWHSTZEM-UHFFFAOYSA-N 1,3-phenylenediamine Chemical compound NC1=CC=CC(N)=C1 WZCQRUWWHSTZEM-UHFFFAOYSA-N 0.000 claims description 6
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- UWCPYKQBIPYOLX-UHFFFAOYSA-N benzene-1,3,5-tricarbonyl chloride Chemical compound ClC(=O)C1=CC(C(Cl)=O)=CC(C(Cl)=O)=C1 UWCPYKQBIPYOLX-UHFFFAOYSA-N 0.000 claims description 5
- 239000012530 fluid Substances 0.000 claims description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
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- 239000000463 material Substances 0.000 description 27
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 26
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- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 25
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- NGNBDVOYPDDBFK-UHFFFAOYSA-N 2-[2,4-di(pentan-2-yl)phenoxy]acetyl chloride Chemical compound CCCC(C)C1=CC=C(OCC(Cl)=O)C(C(C)CCC)=C1 NGNBDVOYPDDBFK-UHFFFAOYSA-N 0.000 description 3
- SGVYKUFIHHTIFL-UHFFFAOYSA-N 2-methylnonane Chemical compound CCCCCCCC(C)C SGVYKUFIHHTIFL-UHFFFAOYSA-N 0.000 description 3
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- FDQSRULYDNDXQB-UHFFFAOYSA-N benzene-1,3-dicarbonyl chloride Chemical compound ClC(=O)C1=CC=CC(C(Cl)=O)=C1 FDQSRULYDNDXQB-UHFFFAOYSA-N 0.000 description 3
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- NHTMVDHEPJAVLT-UHFFFAOYSA-N Isooctane Chemical compound CC(C)CC(C)(C)C NHTMVDHEPJAVLT-UHFFFAOYSA-N 0.000 description 2
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- LXEJRKJRKIFVNY-UHFFFAOYSA-N terephthaloyl chloride Chemical compound ClC(=O)C1=CC=C(C(Cl)=O)C=C1 LXEJRKJRKIFVNY-UHFFFAOYSA-N 0.000 description 2
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- UWHSPZZUAYSGTB-UHFFFAOYSA-N 1,1,3,3-tetraethylurea Chemical compound CCN(CC)C(=O)N(CC)CC UWHSPZZUAYSGTB-UHFFFAOYSA-N 0.000 description 1
- AVQQQNCBBIEMEU-UHFFFAOYSA-N 1,1,3,3-tetramethylurea Chemical compound CN(C)C(=O)N(C)C AVQQQNCBBIEMEU-UHFFFAOYSA-N 0.000 description 1
- GEYOCULIXLDCMW-UHFFFAOYSA-N 1,2-phenylenediamine Chemical compound NC1=CC=CC=C1N GEYOCULIXLDCMW-UHFFFAOYSA-N 0.000 description 1
- CYSGHNMQYZDMIA-UHFFFAOYSA-N 1,3-Dimethyl-2-imidazolidinon Chemical compound CN1CCN(C)C1=O CYSGHNMQYZDMIA-UHFFFAOYSA-N 0.000 description 1
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- UENRXLSRMCSUSN-UHFFFAOYSA-N 3,5-diaminobenzoic acid Chemical compound NC1=CC(N)=CC(C(O)=O)=C1 UENRXLSRMCSUSN-UHFFFAOYSA-N 0.000 description 1
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- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- CWNSVVHTTQBGQB-UHFFFAOYSA-N N,N-Diethyldodecanamide Chemical compound CCCCCCCCCCCC(=O)N(CC)CC CWNSVVHTTQBGQB-UHFFFAOYSA-N 0.000 description 1
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 1
- SUAKHGWARZSWIH-UHFFFAOYSA-N N,N‐diethylformamide Chemical compound CCN(CC)C=O SUAKHGWARZSWIH-UHFFFAOYSA-N 0.000 description 1
- YGYAWVDWMABLBF-UHFFFAOYSA-N Phosgene Chemical group ClC(Cl)=O YGYAWVDWMABLBF-UHFFFAOYSA-N 0.000 description 1
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- ISKQADXMHQSTHK-UHFFFAOYSA-N [4-(aminomethyl)phenyl]methanamine Chemical compound NCC1=CC=C(CN)C=C1 ISKQADXMHQSTHK-UHFFFAOYSA-N 0.000 description 1
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- 238000007711 solidification Methods 0.000 description 1
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- 229910021642 ultra pure water Inorganic materials 0.000 description 1
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- RSJKGSCJYJTIGS-UHFFFAOYSA-N undecane Chemical compound CCCCCCCCCCC RSJKGSCJYJTIGS-UHFFFAOYSA-N 0.000 description 1
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Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/12—Composite membranes; Ultra-thin membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/56—Polyamides, e.g. polyester-amides
Definitions
- the present invention relates to a composite semipermeable membrane useful for selective separation of liquid mixtures, and a method for manufacturing the same.
- membrane separation methods include microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, and reverse osmosis membranes. It is used for the production of industrial ultrapure water, wastewater treatment, and recovery of valuable materials.
- the operation design is such that the chlorine added in pretreatment does not come into contact with the membrane, but due to an operational error, leaked chlorine comes into contact with the membrane, causing the membrane to oxidize. There is a risk of deterioration. Therefore, studies have been conducted to improve the chlorine resistance of these composite semipermeable membranes in order to reduce the risk of membrane deterioration due to chlorine leakage and extend the membrane life.
- Patent Document 3 As methods for improving chlorine resistance, a method of improving the monomer components forming the separation functional layer (Patent Document 3) and a method of forming a protective layer on the separation functional layer (Patent Document 4) are known.
- Patent Document 3 discloses a composite semipermeable membrane using sodium m-phenylenediamine-4-sulfonate as a polyfunctional amine forming a separation functional layer; A composite semipermeable membrane using a compound having hexafluoroalcohol as a side chain as a polyfunctional amine forming a separation functional layer has been disclosed.
- the composite semipermeable membranes described in Patent Documents 3 and 4 have chlorine resistance, membranes having both water permeability and removability have not been obtained. Therefore, an object of the present invention is to provide a composite semipermeable membrane having high water permeability and high removability even after contact with chlorine.
- the composite semipermeable membrane of the present invention has the following configuration.
- the separation functional layer has a plurality of protrusions made of a thin film containing crosslinked aromatic polyamide
- the average number density of protrusions having a height of 1/5 or more of the 10-point average surface roughness is 13.0 pieces/ ⁇ m or more, [1] to [4] above. ]
- the crosslinked aromatic polyamide includes a polyamide that is a polymer of trimesic acid chloride and m-phenylenediamine.
- the composite semipermeable membrane according to any one of [1] to [5] above.
- a method for manufacturing a composite semipermeable membrane comprising: [8] An element comprising the composite semipermeable membrane according to any one of [1] to [6] above.
- a fluid separation device comprising the composite semipermeable membrane according to any one of [1]
- a composite semipermeable membrane that has high water permeability and exhibits high removability even after contact with chlorine can be obtained.
- FIG. 1 is a cross-sectional view of a composite semipermeable membrane according to an embodiment of the present invention.
- FIG. 2 is a schematic diagram showing the structure of a protrusion made of a thin film in the separation functional layer.
- FIG. 3 is an enlarged view showing the structure of the protrusion.
- FIG. 4 is a schematic diagram showing the apparent height of the protrusion.
- ⁇ in the numerical range is a range that includes the numbers before and after it; for example, "0% by mass to 100% by mass” means a range of 0% by mass or more and 100% by mass or less. .
- FIG. 1 shows the structure of a composite semipermeable membrane 1 in this embodiment.
- the composite semipermeable membrane 1 according to the present embodiment includes a microporous support layer 3 and a separation functional layer 4 provided on the microporous support layer 3.
- the composite semipermeable membrane 1 may further include a base material 2.
- the "vertical” direction means the thickness direction of the composite semipermeable membrane, that is, the direction perpendicular to the membrane surface direction of the composite semipermeable membrane, and is the y-axis direction shown in FIGS. 1, 2, 3, and 4. Additionally, the separation functional layer is placed “on top” of the microporous support layer. In other words, the positive side of the y-axis is “up” and the negative side is “down.” Note that the x-axis direction shown in FIGS. 1, 2, 3, and 4 is the membrane surface direction of the composite semipermeable membrane.
- the microporous support layer 3 may be formed on the base material 2, and the composite semipermeable membrane 1 according to the embodiment of the present invention includes the base material 2 and the microporous support layer formed on the base material 2. It may have a support membrane including layer 3.
- the separation functional layer substantially has separation performance.
- the microporous support layer has substantially no ability to separate ions, etc., and can provide strength to the separation functional layer.
- the support membrane may include a base material and a microporous support layer, or the support membrane may not have a base material and may be composed only of the microporous support layer. good. That is, the microporous support layer may be a support membrane.
- the base material examples include fabrics made of polyester polymers, polyamide polymers, polyolefin polymers, and mixtures or copolymers thereof.
- a polyester polymer fabric with high mechanical and thermal stability is preferred.
- As the form of the fabric long fiber nonwoven fabrics, short fiber nonwoven fabrics, and even woven and knitted fabrics can be preferably used.
- the microporous support layer has a large number of pores that communicate from one side to the opposite side.
- the pore size or pore size distribution of the pores in the microporous support layer There are no particular limitations on the pore size or pore size distribution of the pores in the microporous support layer.
- the microporous support layer has pores with a symmetrical structure of uniform pore size, or has an asymmetric structure with pores that gradually increase in size from one side to the other, and the pores have a smaller pore size on the side. It is preferable to have pores having a structure in which the pore size on the surface is 0.1 to 100 nm.
- Materials for the microporous support layer include homopolymers such as polysulfone (hereinafter referred to as "PSf"), polyethersulfone, polyamide, polyester, cellulose polymer, vinyl polymer, polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfone, and polyphenylene oxide. or a copolymer, and these can be used alone or in a blend.
- Examples of the cellulose polymer include cellulose acetate and cellulose nitrate
- examples of the vinyl polymer include polyethylene, polypropylene, polyvinyl chloride, and polyacrylonitrile.
- homopolymers or copolymers such as PSf, polyamide, polyester, cellulose acetate, cellulose nitrate, polyvinyl chloride, polyacrylonitrile, polyphenylene sulfide, polyphenylene sulfide sulfone are preferable, and cellulose acetate, PSf , polyphenylene sulfide sulfone, and polyphenylene sulfone are more preferred, and PSf is particularly preferred because it has high chemical, mechanical, and thermal stability and is easy to mold.
- the weight average molecular weight (hereinafter referred to as "M w ”) of PSf is preferably 10,000 to 200,000, more preferably 15,000 to 100,000.
- M w weight average molecular weight
- the weight average molecular weight refers to a polystyrene equivalent value measured by gel permeation chromatography (GPC).
- the thickness of the base material and microporous support layer affects the strength of the composite semipermeable membrane and the packing density when it is used as an element. From the viewpoint of obtaining good mechanical strength and packing density, the total thickness of the base material and the microporous support layer is preferably 30 to 300 ⁇ m, more preferably 100 to 220 ⁇ m. Further, the thickness of the microporous support layer is preferably 20 to 100 ⁇ m. The thickness of the base material and the microporous support layer can be determined by calculating the average value of the thicknesses of 20 points measured at 20 ⁇ m intervals in the direction perpendicular to the thickness direction (in the plane direction of the membrane) during cross-sectional observation. Can be done.
- the separation functional layer in the composite semipermeable membrane of this embodiment is a layer responsible for the solute separation function, and contains crosslinked aromatic polyamide.
- the separation functional layer preferably contains crosslinked aromatic polyamide as a main component.
- “Mainly composed of crosslinked aromatic polyamide” means that the mass proportion of crosslinked aromatic polyamide in the separation functional layer is 50% by mass or more.
- the mass proportion of the crosslinked aromatic polyamide in the separation functional layer is preferably 80% by mass or more, more preferably 90% by mass or more, and the separation functional layer is substantially composed only of the crosslinked aromatic polyamide. It is more preferable that the When the separation functional layer is substantially composed only of crosslinked aromatic polyamide, it is intended that the mass proportion of the crosslinked aromatic polyamide in the separation functional layer is 99% by mass or more.
- the proportion of crosslinked aromatic polyamide in the separation functional layer of the composite semipermeable membrane can be calculated by nuclear magnetic resonance measurement (hereinafter referred to as "NMR measurement").
- NMR measurement nuclear magnetic resonance measurement
- the base material is physically peeled off from the composite semipermeable membrane, and the microporous support layer and separation functional layer are recovered.
- the recovered microporous support layer and separation functional layer were allowed to stand at 25°C for 24 hours, dried, and then added little by little into a beaker containing dichloromethane and stirred to dissolve the polymer constituting the microporous support layer. dissolve.
- the insoluble matter in the beaker is collected with a filter paper, the obtained insoluble matter is placed in a beaker containing dichloromethane and stirred, and the process of collecting the insoluble matter in the beaker is performed to form a microporous support layer in the dichloromethane solution. Repeat until the elution of the desired polymer is no longer detectable.
- the collected insoluble matter is dried in a vacuum dryer to remove remaining dichloromethane, and the obtained insoluble matter is isolated as a powder sample by freeze-pulverization.
- This powdered sample that is, the separation functional layer
- This powdered sample is immersed in a high-concentration and high-temperature sodium hydroxide aqueous solution until the solid content is dissolved, thereby alkaline hydrolyzing the separation functional layer, and 1 H of the obtained solution.
- NMR measurement It is possible to perform NMR measurement and quantify the monomer from the area of the obtained peak.
- the mass-based proportion of the monomer having an aromatic ring corresponds to the mass-based proportion of the crosslinked aromatic polyamide.
- crosslinked aromatic polyamide examples include aramid compounds, and the aramid compounds may also contain non-aromatic moieties in their molecular structure.
- crosslinked wholly aromatic polyamide is more preferable from the viewpoint of rigidity, chemical stability, and/or durability against operating pressure.
- a crosslinked aromatic polyamide can be formed by interfacial polycondensation of a polyfunctional aromatic amine and a polyfunctional aromatic acid halide.
- at least one of the polyfunctional aromatic amine and the polyfunctional aromatic acid halide contains a trifunctional or higher functional compound.
- a "polyfunctional aromatic amine” has two or more amino groups of at least one of a primary amino group and a secondary amino group in one molecule, and at least one of the amino groups is a secondary amino group. It means an aromatic amine which is a primary amino group.
- polyfunctional aromatic amines examples include o-phenylenediamine, m-phenylenediamine (hereinafter referred to as "m-PDA”), p-phenylenediamine, o-xylylenediamine, m-xylylenediamine, and p-xylylenediamine.
- o-diaminopyridine m-diaminopyridine, p-diaminopyridine, etc.
- a polyfunctional aromatic amine in which two amino groups are bonded to an aromatic ring in any of the ortho, meta, and para positions, 1 , 3,5-triaminobenzene, 1,2,4-triaminobenzene, 3,5-diaminobenzoic acid, 3-aminobenzylamine, 4-aminobenzylamine, and other polyfunctional aromatic amines.
- m-PDA p-phenylenediamine, or 1,3,5-triaminobenzene is preferably used from the viewpoint of improving the selective separation property, permeability, and heat resistance of the membrane.
- m-PDA it is more preferable to use m-PDA because of its ease of availability and handling.
- polyfunctional aromatic amines may be used alone or in combination of two or more.
- Polyfunctional aromatic acid halide means an aromatic acid halide having at least two halogenated carbonyl groups in one molecule.
- examples of trifunctional acid halides include trimesic acid chloride
- examples of difunctional acid halides include biphenyldicarboxylic acid dichloride, azobenzenedicarboxylic acid dichloride, terephthalic acid chloride, isophthalic acid chloride, naphthalenedicarboxylic acid chloride, etc.
- acid chlorides are preferred, particularly acid halides of 1,3,5-benzenetricarboxylic acid from the viewpoint of economy, ease of availability, ease of handling, and ease of reactivity.
- Trimesic acid chloride (hereinafter referred to as "TMC”) is preferred.
- the polyfunctional aromatic acid halide is preferably a polyfunctional aromatic acid chloride, and from the viewpoint of improving the selective separation property and heat resistance of the membrane, A polyfunctional aromatic acid chloride having 2 to 4 carbonyl chloride groups in one molecule is preferred.
- crosslinked aromatic polyamide is a polyamide that is a polymer of trimesic acid chloride and m-phenylenediamine.
- the separation functional layer in the composite semipermeable membrane of this embodiment is composed of a thin film.
- the above explanation regarding the composition of the separation functional layer also applies to thin films. That is, in the above description, "separation functional layer” may be read as "thin film”.
- FIG. 2 is a schematic diagram showing the structure of a protrusion made of a thin film in a cross section perpendicular to the membrane surface direction of a composite semipermeable membrane.
- FIG. 3 is a schematic diagram showing the structure of a protrusion made of a thin film in a cross section perpendicular to the membrane surface direction of a composite semipermeable membrane, and is a diagram showing the protrusion more enlarged than in FIG. 2.
- a protrusion is a structure formed by the thin film 5 of the separation functional layer, and is defined by two convex portions (also referred to as recesses) that are adjacent to each other in the x direction toward the microporous support layer 3 in the thin film 5. (Fig. 3).
- FIG. 3 shows an example in which one of both ends (vertex of the recess) of the protrusion (convex part 6) is separated from the surface of the microporous support layer 3, and the other is in contact with the surface. Note that both ends of the protrusion may be in contact with the microporous support layer 3, or both ends may be separated from the microporous support layer 3.
- the height of the surface of the microporous support layer 3 is 0% in the y-axis direction passing through the apex of the protrusion (protrusion 6), and the height of the protrusion (protrusion 6) is 0%.
- the apex is 100% of the height.
- the "apex of the protrusion" in the "apparent height of the protrusion” means the farthest position within the protrusion from the microporous support layer.
- An image of a cross section of the composite semipermeable membrane perpendicular to the membrane surface direction and having a length of 2.0 ⁇ m in the membrane surface direction is obtained by the following procedure.
- a sample section having a cross section perpendicular to the membrane surface direction of the composite semipermeable membrane can be obtained by a frozen ultrathin section method.
- cross-sectional observation can be performed using an electron microscope such as a scanning electron microscope (SEM, FE-SEM), a transmission electron microscope (TEM), or a scanning transmission electron microscope (STEM). The observation magnification is preferably 10,000 to 100,000 times.
- SEM scanning electron microscope
- TEM transmission electron microscope
- STEM scanning transmission electron microscope
- STEM scanning transmission electron microscope
- the surface of the thin film 5 in the separation functional layer appears as a curve.
- a roughness curve defined based on JIS B 0601 (ISO4287:1997) is determined.
- a cross-sectional image with a width of a reference length L (2.0 ⁇ m) is extracted from the cross section of the sample section in the direction of the average line A (hereinafter also referred to as "average line A") of the roughness curve.
- the "average line” is defined based on JIS B 0601 (ISO4287:1997), and is drawn so that the total area of the area surrounded by the average line and the roughness curve is equal above and below the average line in the measurement range. It is a straight line.
- the altitudes of the highest to fifth peaks on the roughness curve from the average line A (elevations of the highest to fifth peaks from the average line A, Yp1 to 5).
- the average absolute value of and the average absolute value of the elevations of the fifth valley bottom from the lowest valley bottom (elevations Yv1 to 5 of the fifth valley bottom from the lowest valley bottom from the average line A).
- this value expressed in nanometers (nm) is the 10-point average surface roughness in the cross-sectional image (FIG. 2).
- Similar measurements are performed on 10 randomly selected cross-sectional images, and the average value of the obtained 10-point average surface roughness is defined as the 10-point average surface roughness of the composite semipermeable membrane.
- the "height of the protrusion" can be calculated as follows. In a cross-sectional image with a width of 2.0 ⁇ m extracted from 10 cross-sectional images randomly selected as described above, the apparent height Pah of the protrusion is one-fifth or more of the 10-point average surface roughness described above. Regarding a certain protrusion, the distances d1 and d2 between both ends of the protrusion and the average line A in the membrane surface direction of the composite semipermeable membrane are measured. An average value d of distances d1 and d2 is calculated.
- the distances d1 and d2 are distances from the average line A to both ends of the protrusions in a direction perpendicular to the membrane surface direction of the composite semipermeable membrane. Further, both ends of the protrusion are the vertices of two adjacent parts of the thin film that are convex toward the microporous support layer. That is, both ends of the protrusion are the vertices of two recesses sandwiching the protrusion.
- the depth of both ends of the protrusion that is, the distance d1 from the average line A to the apex of the recess on the left side of the protrusion, and the distance from the average line A to the apex of the recess on the right side of the protrusion.
- the sum of the average d of d2 and the distance h from the average line A to the apex of the protrusion is calculated as the height Ph of the protrusion.
- the position where the distance from the average line A toward the microporous support layer is d is 0% of the height, and the apex of the protrusion is 100% of the height.
- the "vertex of the protrusion" in “height of the protrusion” means the position within the protrusion that is farthest from the average line of the roughness curve.
- the height of the protrusion is preferably 70 nm or more, more preferably 90 nm or more, from the viewpoint of ensuring sufficient water permeability of the composite semipermeable membrane. Further, from the viewpoint of suppressing deformation of the protrusions during high-pressure operation and obtaining stable film performance, the height of the protrusions is preferably 1000 nm or less, more preferably 800 nm or less, and even more preferably 400 nm or less. That is, the height of the protrusion is preferably 70 nm to 1000 nm.
- the height of the projections can be determined, for example, by the concentration of a polyfunctional aromatic amine in an aqueous solution of a polyfunctional aromatic amine, or the difference between a microporous support layer in contact with an aqueous solution of a polyfunctional aromatic amine and an organic solvent solution of a polyfunctional aromatic acid halide. It can be adjusted by changing the temperature of contact.
- Thickness of a thin film means the shortest distance from a point on the surface of the thin film to the opposite surface.
- the thickness of the thin film can be measured by photographing a cross section of the protrusion perpendicular to the membrane surface direction of the composite semipermeable membrane using a transmission electron microscope (TEM), and importing the cross-sectional photograph into image analysis software for analysis.
- the observation magnification may be appropriately determined depending on the thickness of the thin film. For example, if the thickness of the thin film is approximately 10 to 100 nm, the observation magnification may be set to 50,000 to 100,000 times so that the cross-sectional shape of the thin film can be observed and the measurement is not localized.
- the protrusions to be measured for the thin film thickness are randomly selected from protrusions having a height of one-fifth or more of the 10-point average surface roughness.
- the thickness of the thin film constituting the protrusion, and the ratio of the average thickness T98 of the thin film in the range of 75 to 98% of the height of the protrusion to the average thickness T25 of the thin film in the range of 2 to 25% of the height of the protrusion (T98/T25 ) can be calculated as follows.
- the range of 75 to 98% of the height of the protrusion is also referred to as the "upper part of the protrusion", and the range of 2 to 25% of the height of the protrusion is also referred to as the "lower part of the protrusion”.
- the average value d of the depths d1 and d2 of the recesses on both sides of the protrusion (protrusion 6) in the x-axis direction is calculated.
- position Z at a distance of d from the average line A has a height of 0%
- position B of the apex of the protrusion has a height of 100%. %.
- the thickness of the thin film constituting the protrusion is measured at 10 random locations on each of the upper and lower parts of the protrusion. Similar measurements are performed on five protrusions whose height is one-fifth or more of the 10-point average surface roughness.
- the arithmetic mean value is calculated for the 50 points of the thin film thickness at the lower part of the protrusion. This value is defined as the average thickness T25 of the lower part of the protrusion formed by the thin film in the composite semipermeable membrane.
- the arithmetic mean of the thickness of the thin film in the area above the protrusion is similarly calculated, and this is set as the average thickness T98 of the upper part of the protrusion constituted by the thin film.
- the average thickness T25 of the lower part of the protrusion is set to 13 to 13. Preferably, it is 24 nm.
- the thickness of the thin film constituting the protrusions is determined by the temperature and heating temperature at which the microporous support layer in which the polyfunctional aromatic amine aqueous solution is brought into contact with the organic solvent solution of the polyfunctional aromatic acid halide, and the crosslinked aromatic polyamide described below. It can be adjusted by a step of bringing a solution containing a compound containing an amide group into contact with the layer containing the amide group.
- the ratio (T98/T25) of the average thickness T98 of the upper part of the protrusion to the average thickness T25 of the lower part of the protrusion is preferably 0.95 or less, and more preferably 0.70 to 0.92.
- Composite semipermeable membranes are generally used in layers, with a channel material inserted between the membranes. When T98/T25 satisfies this range, the thin film is thin and flexible at the top of the protrusion, and thick and strong at the bottom of the protrusion, so even if the protrusion rubs against the channel material or other composite semipermeable membrane during use, The force is distributed under the protrusion, reducing damage and maintaining the salt removal rate.
- the separation functional layer may contain amide groups derived from the polymerization of polyfunctional aromatic amines and polyfunctional aromatic acid halides, and amino groups and carboxy groups derived from unreacted functional groups.
- the ratio of oxygen atoms to nitrogen atoms (O/N ratio) in the protrusion is obtained by analyzing using electron energy-loss spectroscopy (EELS) during TEM observation.
- EELS electron energy-loss spectroscopy
- the present inventors investigated the O/N ratio in the range of 2 to 25% of the apparent height of the protrusion for protrusions whose apparent height Pah is one-fifth or more of the above-mentioned 10-point average surface roughness.
- a composite semipermeable membrane that satisfies y/x ⁇ 1.3 has particularly high water permeability. It has been found that it has removability and also shows high removability even after contact with chlorine.
- x and y are monomer concentrations such as polyfunctional aromatic amines and polyfunctional aromatic acid halides, additives that may be used in interfacial polycondensation, and compounds containing amide groups in the layer containing the crosslinked aromatic polyamide described below. This can be adjusted by introducing a step of contacting a solution containing .
- the O/N ratio in the main skeleton repeating unit of the crosslinked aromatic polyamide is the same both above and below the protrusion, the O/N ratio at the protrusion is substantially (crosslinked aromatic It is proportional to (the carboxy group present at the end of the polyamide)/(the amino group present at the end of the crosslinked aromatic polyamide).
- the terminal functional groups also affect the removal performance and water permeability of the composite semipermeable membrane. In a region where the density of amino groups is high, the separation functional layer has a sparse structure and has low resistance to water permeation, increasing water permeability, but the solute removal performance is insufficient.
- the separation functional layer has a dense structure and has a high water permeation resistance, so the water permeability is low, but the solute removal performance is improved.
- the O/N ratio gradient structure refers to a structure in which the O/N ratio is different between the upper part and the lower part of the protrusion, and the O/N ratio is higher on the upper part of the protrusion than on the lower part. .
- the protrusions contain sufficient carboxyl groups in the range of 75 to 98% of the apparent height of the protrusions that are most easily accessible to raw water, so that the electrostatic field formed by charges It is preferable that y ⁇ 0.90 be satisfied, and it is more preferable that y ⁇ 1.2 be satisfied from the viewpoint of expected improvement in salt removability due to the hydrophilicity of the carboxy group and improvement in water permeability due to the hydrophilicity of the carboxy group.
- y ⁇ 2.0 from the viewpoint of suppressing clogging of pores constituted by the crosslinked aromatic polyamide due to strong hydrogen bonds between the molecules of the crosslinked aromatic polyamide or between carboxyl groups within the molecule, it is preferable that y ⁇ 2.0. That is, 0.90 ⁇ y ⁇ 2.0 is preferable.
- x which is the average value of the O/N ratio in the range of 2 to 25% of the apparent height of the protrusion
- y which is the average value of the O/N ratio in the range of 75 to 98% of the apparent height of the protrusion
- the protrusions preferably satisfy x ⁇ 0.50 from the viewpoint of achieving both water permeability and removal performance by appropriate amino group density. Furthermore, although the contribution is small compared to the 75% to 98% portion of the apparent height of the protrusion, by satisfying x ⁇ 0.50, oxidative deterioration that occurs when the oxidizing agent reaches the root of the protrusion can also be suppressed. On the other hand, from the viewpoint of suppressing clogging of pores constituted by the crosslinked aromatic polyamide due to strong hydrogen bonds between the molecules of the crosslinked aromatic polyamide or between carboxyl groups within the molecule, it is preferable that x ⁇ 2.0. That is, 0.50 ⁇ x ⁇ 2.0 is preferable.
- the average number density of the protrusions in the composite semipermeable membrane according to this embodiment is 13.0% from the viewpoint of obtaining sufficient water permeability and from the viewpoint of suppressing the deformation of the protrusions during pressurization and obtaining stable performance. It is preferably 0 pieces/ ⁇ m or more, and more preferably 15.0 pieces/ ⁇ m or more. Further, from the viewpoint that the growth of the protrusions sufficiently progresses and it is easy to obtain a composite semipermeable membrane having the desired water permeability, the above-mentioned average number density of the protrusions is preferably 50.0 pieces/ ⁇ m or less, and 40.0 ⁇ m or less. More preferably, the number is 0 pieces/ ⁇ m or less.
- the average number density of protrusions is preferably 13.0 pieces/ ⁇ m to 50.0 pieces/ ⁇ m.
- the average number density of the protrusions described above can be adjusted by changing the material of the microporous support layer, changing the concentration of the material used for the microporous support layer, for example, changing the PSf concentration, and the time and temperature of interfacial polycondensation.
- the average number density of protrusions is determined by the 10-point average surface roughness in a cross-sectional image whose length in the membrane surface direction is 2.0 ⁇ m extracted from a cross-sectional image perpendicular to the membrane surface direction of a composite semipermeable membrane selected at random.
- the separation functional layer is preferably placed on the surface side of the composite semipermeable membrane, and is preferably placed on the primary filtration side. More preferred.
- Method for manufacturing a composite semipermeable membrane is not particularly limited as long as a composite semipermeable membrane satisfying the desired characteristics described above can be obtained, but for example, it can be manufactured by the following method. Can be done.
- a method for manufacturing a composite semipermeable membrane having a microporous support layer and a separation functional layer provided on the microporous support layer includes: forming a layer containing a crosslinked aromatic polyamide on the microporous support layer by interfacial polycondensation using an aqueous polyfunctional aromatic amine solution and an organic solvent solution of a polyfunctional aromatic acid halide; contacting the layer containing the crosslinked aromatic polyamide with a solution containing a compound containing an amide group; Equipped with
- PSf is dissolved in a good solvent for PSf to prepare a microporous support layer stock solution.
- a good solvent for PSf for example, N,N-dimethylformamide (hereinafter referred to as "DMF") is preferable.
- the concentration of PSf in the microporous support layer stock solution is preferably 12 to 25% by mass, more preferably 14 to 23% by mass.
- the higher the polymer concentration (i.e., solid content concentration) in the polymer solution the higher the number density of particles on the surface of the microporous support layer, which results in a microporous support layer with a higher number density of protrusions on the separation functional layer.
- the water permeability also increases.
- the surface pore diameter of the microporous support layer can be adjusted, and the appropriate height and/or height can be adjusted during the formation of the separation functional layer.
- a protrusion with an apparent height is formed.
- concentration of PSf in the stock solution of the microporous support layer within this range, it is possible to achieve both strength and permeability of the resulting microporous support layer.
- concentration of the material in the stock solution of the microporous support layer can be adjusted as appropriate depending on the material used, the good solvent, and the like.
- the obtained microporous support layer stock solution is applied to the surface of the substrate and immersed in a coagulation bath containing a non-solvent of PSf.
- a non-solvent for PSf contained in the coagulation bath for example, water is preferable.
- the coagulation bath may be composed only of a non-solvent for PSf, or may contain a good solvent for PSf to the extent that the stock solution of the microporous support layer can be coagulated.
- the solvent remaining in the membrane may be removed by washing the obtained support membrane before forming the separation functional layer.
- a polyfunctional aromatic amine and a polyfunctional aromatic acid chloride are mixed on the support film obtained in "(2-1) Formation of support film".
- the method of polymerization and solidification will be described as an example.
- interfacial polycondensation method is most preferred from the viewpoint of productivity and performance. The interfacial polycondensation process will be explained below.
- the step of interfacial polycondensation includes (a) a step of bringing an aqueous solution containing a polyfunctional aromatic amine into contact with a support membrane, and (b) a step of bringing an organic solvent solution containing a polyfunctional aromatic acid chloride into contact with a polyfunctional aromatic amine. (c) draining the organic solvent solution after contact; and (d) separating the separation functional layer produced by interfacial polycondensation from the amide group. It is preferable to include the steps of: (e) cleaning the composite semipermeable membrane with hot water; and (e) cleaning the composite semipermeable membrane with hot water.
- the microporous support layer As the microporous support layer, the polyfunctional aromatic amine, and the polyfunctional aromatic acid halide, those mentioned above can be mentioned, and preferred ones are also the same.
- the concentration of the polyfunctional aromatic amine in the aqueous polyfunctional aromatic amine solution is preferably in the range of 0.1 to 20% by mass, and preferably in the range of 0.5 to 15% by mass. More preferred. When the concentration of the polyfunctional aromatic amine is within this range, the manufactured composite semipermeable membrane can have sufficient solute removal performance and water permeability. Note that two or more types of polyfunctional aromatic amines may be used.
- the polyfunctional aromatic amine aqueous solution does not contain surfactants, organic solvents, alkaline compounds, antioxidants, etc. as long as they do not interfere with the reaction between the polyfunctional aromatic amine and the polyfunctional aromatic acid halide. You can leave it there.
- the surfactant has the effect of improving the wettability of the support membrane surface and reducing the interfacial tension between the polyfunctional aromatic amine aqueous solution and the nonpolar solvent.
- the organic solvent may act as a catalyst for the interfacial polycondensation reaction, and by adding the organic solvent, the interfacial polycondensation reaction may be carried out efficiently.
- the polyfunctional aromatic amine aqueous solution is preferably brought into contact with the support membrane uniformly and continuously.
- a method of coating a polyfunctional aromatic amine aqueous solution on the support membrane or a method of immersing the support membrane in a polyfunctional aromatic amine aqueous solution can be mentioned.
- the contact time between the support membrane and the polyfunctional aromatic amine aqueous solution is preferably 1 second to 10 minutes, more preferably 3 seconds to 3 minutes.
- the support membrane after contact with the polyfunctional aromatic amine aqueous solution is held vertically and the excess aqueous solution is naturally drained.
- Examples include a method of letting the liquid flow down, or a method of forcibly draining the liquid by blowing an air stream of nitrogen or the like from an air nozzle. Further, after draining, the membrane surface can be dried to partially remove water from the polyfunctional aromatic amine aqueous solution.
- the polyfunctional aromatic acid chloride includes, for example, TMC, biphenyldicarboxylic acid dichloride, azobenzenedicarboxylic acid dichloride, terephthalic acid chloride, isophthalic acid chloride, naphthalenedicarboxylic acid chloride, 2,5-furandicarboxylic acid chloride. etc. These polyfunctional aromatic acid chlorides may be used alone or in combination of two or more.
- the organic solvent must be immiscible with water, dissolve the polyfunctional aromatic acid chloride, do not attack the support membrane, and be inert to the polyfunctional aromatic amine and the polyfunctional aromatic acid chloride. is preferred.
- the organic solvent include hydrocarbon compounds such as n-nonane, n-decane, n-undecane, n-dodecane, isooctane, isodecane, and isododecane, and mixed solvents thereof.
- the concentration of polyfunctional aromatic acid chloride in the organic solvent solution is preferably 0.01 to 10% by mass, more preferably 0.02 to 4% by mass, and more preferably 0.03 to 2% by mass. It is even more preferable that there be.
- concentration of the polyfunctional aromatic acid chloride is 0.01% by mass or more, polymerization can proceed at a sufficient reaction rate.
- concentration of the polyfunctional aromatic acid chloride is 10% by mass or less, the occurrence of side reactions during polymerization can be suppressed.
- the organic solvent solution may contain a compound such as a surfactant, if necessary, as long as it does not inhibit polymerization.
- the method of contacting the organic solvent solution of polyfunctional aromatic acid chloride with the support membrane that has been brought into contact with the polyfunctional aromatic amine aqueous solution is the same as the method of contacting the polyfunctional aromatic amine aqueous solution with the support membrane in step (a). You can do the same.
- a separation functional layer begins to be formed by bringing the polyfunctional aromatic acid chloride solution into contact with the support membrane that has been brought into contact with the polyfunctional aromatic amine aqueous solution.
- the temperature at which the microporous support layer brought into contact with the aqueous solution containing the polyfunctional aromatic amine and the solution in which the polyfunctional aromatic acid halide is dissolved is preferably 25 to 60°C, and preferably 30 to 55°C. °C is more preferable.
- the temperature By setting the temperature to 25° C. or higher, the height and/or apparent height of the protrusion becomes sufficient. Further, by setting the temperature to 60° C. or lower, the reaction rate becomes appropriate, the increase in the thickness of the thin film and the progress of coalescence of protrusions are suppressed, and sufficient water permeability is easily obtained in the manufactured composite semipermeable membrane. In addition, the amount of amine initially supplied from the support film to the interfacial polycondensation site becomes appropriate, suppressing the amount of amino groups in the range of 2 to 25% of the apparent height of the protrusions, and making it easier to satisfy x ⁇ 0.50. .
- the contact temperature is 25 to 60°C
- the number of protrusions increases and the surface area of the reaction interface increases, which increases the amount of polyamide and suppresses the increase in the average thicknesses T25 and T98 of the protrusions.
- the support film may be heated, or a heated solution of a polyfunctional aromatic acid halide in an organic solvent may be brought into contact with the support film.
- the temperature of the membrane surface immediately after the polyfunctional aromatic amine aqueous solution and the polyfunctional aromatic acid halide solution are brought into contact can be measured with a non-contact thermometer such as a radiation thermometer.
- the separation functional layer and the support membrane may be heat-treated.
- the heating temperature is preferably 50 to 180°C, more preferably 60 to 160°C, even more preferably 80 to 150°C.
- step (c) the organic solvent is removed from the support membrane and the separation functional layer by draining the organic solvent solution after the reaction.
- the organic solvent can be removed, for example, by holding the membrane vertically and removing the excess organic solvent by gravity, by blowing air with a blower to dry and remove the organic solvent, or by using a mixed fluid of water and air. A method of removing excess organic solvent can be used.
- step (d) the functional layer produced by interfacial polycondensation is brought into contact with solution A containing a compound containing an amide group.
- the compound containing an amide group include a chain amide compound, a cyclic amide compound, and the like.
- chain amide compounds include N-methylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, N,N-diisopropylformamide, N,N-dibutylformamide, N, Examples include N-diethylacetamide, tetramethylurea, tetraethylurea, N,N-diethyldodecanamide and the like.
- cyclic amide compound examples include N-methylpyrrolidinone, ⁇ -butyrolactam, ⁇ -caprolactam, 1,3-dimethyl-2-imidazolidinone, N,N'-dimethylpropylene urea, and the like.
- the separation functional layer contains a polyamide having a polyfunctional aromatic acid chloride end, a carboxy end obtained by hydrolyzing the acid chloride end, a polyamide having a polyfunctional aromatic amino group end, an oligomer, and an unreacted monomer. ing.
- solution A containing a compound containing an amide group By contacting solution A containing a compound containing an amide group, the amide group of solution A and the amino group present in the separation functional layer interact through hydrogen bonding, and oligomers and unreacted monomers having amino groups are separated. Since nitrogen atoms (N) are easily removed from the functional layer, the number of nitrogen atoms (N) contained in the separation functional layer decreases.
- the compound having an amide group acts on the acid chloride terminal and promotes hydrolysis, the amount of carboxy groups contained in the separation functional layer increases, and the number of oxygen atoms (O) also increases.
- the portions in the separation functional layer where the apparent height of the protrusions ranges from 75% to 98% have less steric hindrance than the portions where the apparent height ranges from 2% to 25%, so compounds having an amide group can easily approach them, resulting in the above effects. Great effect. Therefore, for the protrusions in the separation functional layer, y, which is the average value of the O/N ratio in the range of 75% to 98% of the apparent height of the protrusions, becomes large and satisfies y ⁇ 0.90 and y/x ⁇ 1.3.
- the hydrolysis of the acid chloride terminal is promoted and the amino group-containing oligomer and unreacted monomer are removed, so that the polymerization reaction in the protrusion height range of 75 to 98% can be carried out at a protrusion height of 2 to 25%. Since the termination reaction proceeds faster than the polymerization reaction in the % range, it becomes easier to satisfy T98/T25 of 0.95 or less.
- the concentration of the compound containing an amide group in solution A is preferably 0.1 to 40% by mass, more preferably 1.0 to 30% by mass. When the concentration is 0.1% by mass or more, the above effects can be sufficiently obtained. In addition, since the concentration is 40% by mass or less, even if the compound containing an amide group is a good solvent for PSf that forms the support membrane, it will not attack the separation functional layer or the support membrane and suppress a decrease in removal rate. can.
- the time for which the separation functional layer is brought into contact with solution A is preferably within 5 minutes, more preferably within 2 minutes. By keeping the contact time within 5 minutes, the effect on the portion of the protrusion with an apparent height of 2 to 25% is suppressed, making it easier to satisfy y/x ⁇ 1.3.
- the temperature of solution A to be brought into contact is preferably 0 to 50°C, more preferably 5 to 40°C.
- the contacting method include a method of coating the surface of the composite semipermeable membrane with solution A, and a method of immersing the composite semipermeable membrane in solution A.
- step (e) the composite semipermeable membrane is washed with hot water.
- the temperature of the hot water is preferably 40 to 95°C, more preferably 60 to 95°C.
- the temperature of the hot water is 40° C. or higher, unreacted substances and oligomers remaining in the membrane can be sufficiently removed.
- the temperature of the hot water is 95° C. or lower, the degree of shrinkage of the composite semipermeable membrane does not become large, and good permeation performance can be maintained.
- the preferable temperature range of the hot water can be adjusted as appropriate depending on the polyfunctional aromatic amine or polyfunctional aromatic acid chloride used.
- the performance of the composite semipermeable membrane can be improved by introducing a new functional group through a modification treatment using an appropriately selected chemical reaction on the amino groups present in the crosslinked aromatic polyamide.
- new functional groups include alkyl groups, alkenyl groups, alkynyl groups, halogeno groups, hydroxyl groups, ether groups, thioether groups, ester groups, aldehyde groups, nitro groups, nitroso groups, nitrile groups, and azo groups. .
- Composite semi-permeable membranes are made of feed water channel material such as plastic net, permeate water channel material such as tricot, and if necessary, a film to increase pressure resistance, as well as a large number of holes.
- the membrane element is wound around a cylindrical water collecting pipe, and is suitably used as a spiral-type composite semipermeable membrane element.
- a composite semipermeable membrane module can be obtained in which these elements are connected in series or in parallel and housed in a pressure vessel.
- the above-described composite semipermeable membrane, its elements, and modules can be combined with a pump that supplies water to them, a device that pre-treats the water, and the like to configure a fluid separation device.
- a separation device By using this separation device, it is possible to separate feed water into permeated water such as drinking water and concentrated water that has not passed through the membrane, thereby obtaining water suitable for the purpose.
- the feed water to be treated by the composite semipermeable membrane is a liquid mixture containing total dissolved solids (hereinafter referred to as "TDS") of 500 mg/L or more and 100 g/L or less, such as seawater, brine, and waste water.
- TDS refers to the total amount of dissolved solids, and is expressed as "mass divided by volume (mass divided by volume)" or "mass ratio.” According to the definition, it can be calculated from the weight of the residue obtained by evaporating a solution filtered through a 0.45 ⁇ m filter at a temperature between 39.5°C and 40.5°C, but more simply, it can be calculated from the practical salinity (S). converted.
- the higher the solute removal performance of the membrane the better the water quality can be ensured even if the operating pressure is lowered.
- the initial salt removal rate before contact with chlorine is preferably 99.75% or more.
- the salt permeability ratio (SP ratio) before and after the chlorine resistance test described in the example is 2.00 or less.
- the solute removal rate decreases, but as the temperature decreases, the membrane permeation flux also decreases, so it is preferably 5 to 45°C or less.
- scales such as magnesium may occur in feed water with a high solute concentration such as seawater, and there is a concern that membrane deterioration due to high pH operation may occur. Driving in the area is preferred.
- SP ratio (100-salt removal rate after immersion)/(100-salt removal rate before immersion) ⁇ ...Equation (2) Normally, the salt removal rate of composite semipermeable membranes decreases when immersed in chlorine. As the SP ratio becomes larger than 1.00, it means that the salt removal rate of the composite semipermeable membrane decreases due to chlorine immersion.
- Example 1 The support membrane obtained in Reference Example 1 was immersed in a 3.0% by mass aqueous m-phenylenediamine solution for 2 minutes. The support membrane was slowly pulled up vertically and nitrogen was blown from an air nozzle to remove excess aqueous solution from the surface of the support membrane. In an environment controlled at 40°C, a 40°C n-decane solution containing 0.16% by mass of TMC was applied so that the surface of the support membrane was completely wetted. Next, the supporting membrane was heated in an oven at 120°C, and then, in order to remove excess solution from the membrane, the membrane was placed vertically to drain the liquid, and then dried by blowing air at 20°C using a blower. Ta.
- the dried membrane was immersed for 2 minutes at 25° C. in a 10% by mass aqueous solution of N,N-dimethylformamide as a compound containing an amide group. Thereafter, the composite semipermeable membrane of Example 1 was obtained by washing the membrane with 90°C pure water. The height of the protrusions of the composite semipermeable membrane of Example 1 was 102 nm.
- Example 2 was prepared in the same manner as in Example 1, except that the oven temperature was set to 150°C, and after drying by blowing air, it was immersed in a 30.0 mass% N,N-dimethylformamide aqueous solution at 5°C for 2 minutes. A composite semipermeable membrane was obtained.
- Example 3 A composite semipermeable membrane of Example 3 was obtained in the same manner as in Example 1, except that after drying by blowing air, it was immersed in a 10.0 mass % N,N-dimethylformamide aqueous solution at 10° C. for 2 minutes.
- Example 4 A composite semipermeable membrane of Example 4 was obtained in the same manner as in Example 1, except that the temperature of the N,N-dimethylformamide aqueous solution brought into contact was 45°C.
- Example 5 A composite semipermeable membrane of Example 5 was obtained in the same manner as in Example 1 except that the m-phenylenediamine aqueous solution was changed to 6.0% by mass.
- Example 6 A composite semipermeable membrane of Example 6 was obtained in the same manner as in Example 2, except that the concentration of the N,N-dimethylformamide aqueous solution brought into contact was 1.0% by mass.
- Example 7 A composite semipermeable membrane of Example 7 was obtained in the same manner as in Example 1, except that the solution containing the compound containing an amide group to be contacted was changed to ⁇ -caprolactam to obtain a 10.0% by mass ⁇ -caprolactam aqueous solution. .
- Example 8 A composite semipermeable membrane of Example 8 was obtained in the same manner as in Example 2, except that the temperature of the n-decane solution of TMC to be applied was 65°C.
- Example 9 The procedure was carried out in the same manner as in Example 1, except that a 40°C n-decane solution containing 0.16% by mass TMC and 0.016% by mass isophthalic acid chloride was used as the polyfunctional aromatic acid halide solution. A composite semipermeable membrane of Example 9 was obtained.
- Comparative example 1 A composite semipermeable membrane of Comparative Example 1 was obtained in the same manner as in Example 5, except that the step of bringing the dried membrane into contact with a solution containing a compound containing an amide group was not performed.
- Comparative example 2 After applying a 40°C n-decane solution containing 0.16% by weight of TMC so that the surface of the support membrane was completely wet, an n-decane solution containing 0.32% by weight of TMC was further applied to the support membrane, and then 120% A composite semipermeable membrane of Comparative Example 2 was obtained in the same manner as Comparative Example 1 except that it was heated in an oven at .degree.
- Comparative Example 3 Comparative Example 3 was carried out in the same manner as Comparative Example 1, except that the solvent for the TMC solution was isooctane, the solution temperature was 25°C, the coating was carried out in an environment controlled at 25°C, and the oven temperature was 150°C. A composite semipermeable membrane was obtained.
- Comparative example 4 The composite half of Comparative Example 4 was prepared in the same manner as Comparative Example 1, except that the step of placing it in an oven at 120°C was omitted, the temperature of the TMC n-decane solution was 25°C, and the coating was performed in an environment controlled at 25°C. A permeable membrane was obtained.
- Comparative example 5 A composite semipermeable membrane of Comparative Example 5 was obtained in the same manner as Comparative Example 1, except that after drying by blowing air, it was immersed in a 1% by mass tributyl phosphate aqueous solution at 25° C. for 2 minutes.
- Comparative example 6 A composite semipermeable membrane of Comparative Example 6 was obtained in the same manner as Comparative Example 1, except that after drying by blowing air, it was immersed in a 10% by mass isopropyl alcohol aqueous solution at 25° C. for 2 minutes.
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Abstract
The present invention relates to a composite semipermeable membrane having a microporous support layer and a separation function layer that is provided on the microporous support layer, the separation function layer having a plurality of protrusions configured from a thin film containing a cross-linked aromatic polyamide, and x and y, which are measured through TEM-EELS, satisfying the relationship y/x ≥ 1.3. x: Average value of ratio of oxygen atoms (O) to nitrogen atoms (N) in the range of 2-25% of apparent height of protrusions. y: Average value of ratio of O to N in range of 75-98% of apparent height of protrusions.
Description
本発明は、液状混合物の選択的分離に有用な複合半透膜、及びその製造方法に関する。
The present invention relates to a composite semipermeable membrane useful for selective separation of liquid mixtures, and a method for manufacturing the same.
液状混合物の分離に関して、溶媒（例えば水）に溶解した物質（例えば塩類）を除くための技術には様々なものがあるが、近年、省エネルギー及び省資源のためのプロセスとして、膜分離法の利用が拡大している。膜分離法に使用される膜には、精密ろ過膜、限外ろ過膜、ナノろ過膜、逆浸透膜等があり、これらの膜は、例えば塩分、有害物を含んだ水等から飲料水を得る場合や、工業用超純水の製造、排水処理、有価物の回収等に用いられている。
Regarding the separation of liquid mixtures, there are various techniques for removing substances (e.g., salts) dissolved in a solvent (e.g., water), but in recent years, the use of membrane separation methods has become popular as a process for saving energy and resources. is expanding. Membranes used in membrane separation methods include microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, and reverse osmosis membranes. It is used for the production of industrial ultrapure water, wastewater treatment, and recovery of valuable materials.
現在市販されている逆浸透膜及びナノろ過膜の大部分は、支持膜上に塩類等の分離性能を有する分離機能層を被覆した複合半透膜であり、支持膜上にゲル層とポリマーを架橋した活性層を有するものと、支持膜上でモノマーを重縮合した活性層を有するものとの２種類がある。後者の複合半透膜のなかでも、多官能アミンと多官能酸ハロゲン化物との重縮合反応によって得られる架橋ポリアミドを含有する分離機能層を有する複合半透膜（特許文献１及び２）が、透過性及び選択分離性の高い分離膜として広く用いられている。
Most of the reverse osmosis membranes and nanofiltration membranes currently on the market are composite semipermeable membranes in which a support membrane is coated with a separation functional layer that has the ability to separate salts, etc., and a gel layer and a polymer are coated on the support membrane. There are two types: those with a crosslinked active layer and those with an active layer formed by polycondensing monomers on a support membrane. Among the latter composite semipermeable membranes, composite semipermeable membranes having a separation functional layer containing a crosslinked polyamide obtained by a polycondensation reaction of a polyfunctional amine and a polyfunctional acid halide (Patent Documents 1 and 2) are It is widely used as a separation membrane with high permeability and selective separation.
ここで造水プラントなどの各種水処理において、前処理に添加している塩素は原則として膜と接触しないようオペレーション設計されているものの、オペレーションミスにより漏洩した塩素が膜と接触し、膜が酸化劣化するリスクが存在する。そこで塩素漏洩による膜劣化リスクを低減し、膜寿命を長期化する目的で、これら複合半透膜について耐塩素性向上に向けた検討が行われてきた。
In various water treatments such as water production plants, the operation design is such that the chlorine added in pretreatment does not come into contact with the membrane, but due to an operational error, leaked chlorine comes into contact with the membrane, causing the membrane to oxidize. There is a risk of deterioration. Therefore, studies have been conducted to improve the chlorine resistance of these composite semipermeable membranes in order to reduce the risk of membrane deterioration due to chlorine leakage and extend the membrane life.
耐塩素性向上方法としては、分離機能層を形成するモノマー成分を改良する方法（特許文献３）及び分離機能層上に保護層を形成する方法（特許文献４）が知られている。
As methods for improving chlorine resistance, a method of improving the monomer components forming the separation functional layer (Patent Document 3) and a method of forming a protective layer on the separation functional layer (Patent Document 4) are known.
耐塩素性の向上を目的に、特許文献３には、分離機能層を形成する多官能アミンとしてｍ－フェニレンジアミン－４－スルホン酸ナトリウムを用いた複合半透膜が、特許文献４には、分離機能層を形成する多官能アミンとして、ヘキサフルオロアルコールを側鎖として有する化合物を用いた複合半透膜が開示されている。しかしながら、特許文献３及び４に記載の複合半透膜は、耐塩素性を有するが、透水性及び除去性を併せもつ膜は得られていない。そこで、本発明は、高い透水性と塩素接触後も高い除去性を有する複合半透膜を提供することを目的とする。
For the purpose of improving chlorine resistance, Patent Document 3 discloses a composite semipermeable membrane using sodium m-phenylenediamine-4-sulfonate as a polyfunctional amine forming a separation functional layer; A composite semipermeable membrane using a compound having hexafluoroalcohol as a side chain as a polyfunctional amine forming a separation functional layer has been disclosed. However, although the composite semipermeable membranes described in Patent Documents 3 and 4 have chlorine resistance, membranes having both water permeability and removability have not been obtained. Therefore, an object of the present invention is to provide a composite semipermeable membrane having high water permeability and high removability even after contact with chlorine.
上記目的を達成するために、本発明の複合半透膜は、以下の構成からなる。
［１］微多孔性支持層と、上記微多孔性支持層上に設けられた分離機能層とを有する複合半透膜であって、
上記分離機能層は、架橋芳香族ポリアミドを含有する薄膜で構成される複数の突起を有し、
透過型電子顕微鏡における電子エネルギー損失分光法（ＴＥＭ－ＥＥＬＳ）により測定される下記ｘ及びｙが、ｙ／ｘ≧１．３を満たす、複合半透膜。
ｘ：上記突起の見かけ高さの２～２５％の範囲における酸素原子（Ｏ）／窒素原子（Ｎ）比の平均値
ｙ：上記突起の見かけ高さの７５～９８％の範囲におけるＯ／Ｎ比の平均値
［２］上記ｙがｙ≧０．９０を満たす、上記［１］に記載の複合半透膜。
［３］上記ｘがｘ≧０．５０を満たす、上記［１］又は［２］に記載の複合半透膜。
［４］上記分離機能層において、上記突起の高さの２～２５％の範囲における上記薄膜の平均厚みＴ２５に対する、上記突起の高さ７５～９８％の範囲における上記薄膜の平均厚みＴ９８の比（Ｔ９８／Ｔ２５）が０．９５以下である、上記［１］～［３］のいずれかに記載の複合半透膜。
［５］上記分離機能層中で、１０点平均面粗さの５分の１以上の高さを有する突起の平均数密度が１３．０個／μｍ以上である、上記［１］～［４］のいずれかに記載の複合半透膜。
［６］上記架橋芳香族ポリアミドが、トリメシン酸クロリドとｍ－フェニレンジアミンの重合物であるポリアミドを含む、
上記［１］～［５］のいずれかに記載の複合半透膜。
［７］微多孔性支持層と、上記微多孔性支持層上に設けられた分離機能層とを有する複合半透膜の製造方法であって、
多官能芳香族アミン水溶液と、多官能芳香族酸ハロゲン化物の有機溶媒溶液とを用い、上記微多孔性支持層上で界面重縮合によって架橋芳香族ポリアミドを含有する層を形成する工程と、
架橋芳香族ポリアミドを含有する上記層にアミド基を含む化合物を含有する溶液を接触させる工程と、
を備える複合半透膜の製造方法。
［８］上記［１］～［６］のいずれかに記載の複合半透膜を備えるエレメント。
［９］上記［１］～［６］のいずれかに記載の複合半透膜を備える流体分離装置。 In order to achieve the above object, the composite semipermeable membrane of the present invention has the following configuration.
[1] A composite semipermeable membrane having a microporous support layer and a separation functional layer provided on the microporous support layer,
The separation functional layer has a plurality of protrusions made of a thin film containing crosslinked aromatic polyamide,
A composite semipermeable membrane in which the following x and y satisfy y/x≧1.3 as measured by electron energy loss spectroscopy in a transmission electron microscope (TEM-EELS).
x: average value of oxygen atom (O)/nitrogen atom (N) ratio in the range of 2 to 25% of the apparent height of the above protrusion y: O/N in the range of 75 to 98% of the apparent height of the above protrusion Average value of ratio [2] The composite semipermeable membrane according to [1] above, wherein y satisfies y≧0.90.
[3] The composite semipermeable membrane according to [1] or [2] above, wherein x satisfies x≧0.50.
[4] In the separation functional layer, the ratio of the average thickness T98 of the thin film in the range of 75 to 98% of the height of the projections to the average thickness T25 of the thin film in the range of 2 to 25% of the height of the projections. The composite semipermeable membrane according to any one of [1] to [3] above, wherein (T98/T25) is 0.95 or less.
[5] In the separation functional layer, the average number density of protrusions having a height of 1/5 or more of the 10-point average surface roughness is 13.0 pieces/μm or more, [1] to [4] above. ] The composite semipermeable membrane according to any one of the above.
[6] The crosslinked aromatic polyamide includes a polyamide that is a polymer of trimesic acid chloride and m-phenylenediamine.
The composite semipermeable membrane according to any one of [1] to [5] above.
[7] A method for producing a composite semipermeable membrane having a microporous support layer and a separation functional layer provided on the microporous support layer,
forming a layer containing a crosslinked aromatic polyamide on the microporous support layer by interfacial polycondensation using an aqueous polyfunctional aromatic amine solution and an organic solvent solution of a polyfunctional aromatic acid halide;
contacting the layer containing the crosslinked aromatic polyamide with a solution containing a compound containing an amide group;
A method for manufacturing a composite semipermeable membrane comprising:
[8] An element comprising the composite semipermeable membrane according to any one of [1] to [6] above.
[9] A fluid separation device comprising the composite semipermeable membrane according to any one of [1] to [6] above.
［１］微多孔性支持層と、上記微多孔性支持層上に設けられた分離機能層とを有する複合半透膜であって、
上記分離機能層は、架橋芳香族ポリアミドを含有する薄膜で構成される複数の突起を有し、
透過型電子顕微鏡における電子エネルギー損失分光法（ＴＥＭ－ＥＥＬＳ）により測定される下記ｘ及びｙが、ｙ／ｘ≧１．３を満たす、複合半透膜。
ｘ：上記突起の見かけ高さの２～２５％の範囲における酸素原子（Ｏ）／窒素原子（Ｎ）比の平均値
ｙ：上記突起の見かけ高さの７５～９８％の範囲におけるＯ／Ｎ比の平均値
［２］上記ｙがｙ≧０．９０を満たす、上記［１］に記載の複合半透膜。
［３］上記ｘがｘ≧０．５０を満たす、上記［１］又は［２］に記載の複合半透膜。
［４］上記分離機能層において、上記突起の高さの２～２５％の範囲における上記薄膜の平均厚みＴ２５に対する、上記突起の高さ７５～９８％の範囲における上記薄膜の平均厚みＴ９８の比（Ｔ９８／Ｔ２５）が０．９５以下である、上記［１］～［３］のいずれかに記載の複合半透膜。
［５］上記分離機能層中で、１０点平均面粗さの５分の１以上の高さを有する突起の平均数密度が１３．０個／μｍ以上である、上記［１］～［４］のいずれかに記載の複合半透膜。
［６］上記架橋芳香族ポリアミドが、トリメシン酸クロリドとｍ－フェニレンジアミンの重合物であるポリアミドを含む、
上記［１］～［５］のいずれかに記載の複合半透膜。
［７］微多孔性支持層と、上記微多孔性支持層上に設けられた分離機能層とを有する複合半透膜の製造方法であって、
多官能芳香族アミン水溶液と、多官能芳香族酸ハロゲン化物の有機溶媒溶液とを用い、上記微多孔性支持層上で界面重縮合によって架橋芳香族ポリアミドを含有する層を形成する工程と、
架橋芳香族ポリアミドを含有する上記層にアミド基を含む化合物を含有する溶液を接触させる工程と、
を備える複合半透膜の製造方法。
［８］上記［１］～［６］のいずれかに記載の複合半透膜を備えるエレメント。
［９］上記［１］～［６］のいずれかに記載の複合半透膜を備える流体分離装置。 In order to achieve the above object, the composite semipermeable membrane of the present invention has the following configuration.
[1] A composite semipermeable membrane having a microporous support layer and a separation functional layer provided on the microporous support layer,
The separation functional layer has a plurality of protrusions made of a thin film containing crosslinked aromatic polyamide,
A composite semipermeable membrane in which the following x and y satisfy y/x≧1.3 as measured by electron energy loss spectroscopy in a transmission electron microscope (TEM-EELS).
x: average value of oxygen atom (O)/nitrogen atom (N) ratio in the range of 2 to 25% of the apparent height of the above protrusion y: O/N in the range of 75 to 98% of the apparent height of the above protrusion Average value of ratio [2] The composite semipermeable membrane according to [1] above, wherein y satisfies y≧0.90.
[3] The composite semipermeable membrane according to [1] or [2] above, wherein x satisfies x≧0.50.
[4] In the separation functional layer, the ratio of the average thickness T98 of the thin film in the range of 75 to 98% of the height of the projections to the average thickness T25 of the thin film in the range of 2 to 25% of the height of the projections. The composite semipermeable membrane according to any one of [1] to [3] above, wherein (T98/T25) is 0.95 or less.
[5] In the separation functional layer, the average number density of protrusions having a height of 1/5 or more of the 10-point average surface roughness is 13.0 pieces/μm or more, [1] to [4] above. ] The composite semipermeable membrane according to any one of the above.
[6] The crosslinked aromatic polyamide includes a polyamide that is a polymer of trimesic acid chloride and m-phenylenediamine.
The composite semipermeable membrane according to any one of [1] to [5] above.
[7] A method for producing a composite semipermeable membrane having a microporous support layer and a separation functional layer provided on the microporous support layer,
forming a layer containing a crosslinked aromatic polyamide on the microporous support layer by interfacial polycondensation using an aqueous polyfunctional aromatic amine solution and an organic solvent solution of a polyfunctional aromatic acid halide;
contacting the layer containing the crosslinked aromatic polyamide with a solution containing a compound containing an amide group;
A method for manufacturing a composite semipermeable membrane comprising:
[8] An element comprising the composite semipermeable membrane according to any one of [1] to [6] above.
[9] A fluid separation device comprising the composite semipermeable membrane according to any one of [1] to [6] above.
本発明によれば、高い透水性を有し、かつ、塩素接触後も高い除去性を示す複合半透膜が得られる。
According to the present invention, a composite semipermeable membrane that has high water permeability and exhibits high removability even after contact with chlorine can be obtained.
以下に、本発明の実施形態について詳細に説明するが、本発明はこれらによって何ら限定されるものではない。
数値範囲の「～」は、その前後の数値を含む範囲であり、例えば、「０質量％～１００質量％」は、０質量％以上であり、かつ、１００質量％以下である範囲を意味する。 Embodiments of the present invention will be described in detail below, but the present invention is not limited thereto.
"~" in the numerical range is a range that includes the numbers before and after it; for example, "0% by mass to 100% by mass" means a range of 0% by mass or more and 100% by mass or less. .
数値範囲の「～」は、その前後の数値を含む範囲であり、例えば、「０質量％～１００質量％」は、０質量％以上であり、かつ、１００質量％以下である範囲を意味する。 Embodiments of the present invention will be described in detail below, but the present invention is not limited thereto.
"~" in the numerical range is a range that includes the numbers before and after it; for example, "0% by mass to 100% by mass" means a range of 0% by mass or more and 100% by mass or less. .
１．複合半透膜
図１に本実施形態における複合半透膜１の構造を示す。図１に示すように、本実施形態に係る複合半透膜１は、微多孔性支持層３と、微多孔性支持層３上に設けられた分離機能層４とを有する。複合半透膜１は、さらに基材２を有してもよい。 1. Composite Semipermeable Membrane FIG. 1 shows the structure of a compositesemipermeable membrane 1 in this embodiment. As shown in FIG. 1, the composite semipermeable membrane 1 according to the present embodiment includes a microporous support layer 3 and a separation functional layer 4 provided on the microporous support layer 3. The composite semipermeable membrane 1 may further include a base material 2.
図１に本実施形態における複合半透膜１の構造を示す。図１に示すように、本実施形態に係る複合半透膜１は、微多孔性支持層３と、微多孔性支持層３上に設けられた分離機能層４とを有する。複合半透膜１は、さらに基材２を有してもよい。 1. Composite Semipermeable Membrane FIG. 1 shows the structure of a composite
以下、「上下」方向とは、複合半透膜の厚み方向、すなわち複合半透膜の膜面方向に垂直な方向を意味し、図１、２、３及び４に示すｙ軸方向である。また、分離機能層は、微多孔性支持層の「上」に配置される。つまり、ｙ軸の正側が「上」で、負側が「下」である。なお、図１、２、３及び４に示すｘ軸方向は、複合半透膜の膜面方向である。
微多孔性支持層３は、基材２上に形成されていてもよく、本発明の実施形態に係る複合半透膜１は、基材２と基材２上に形成された微多孔性支持層３とを含む支持膜を有していてもよい。
分離機能層は実質的に分離性能を有するものである。微多孔性支持層は実質的にイオン等の分離性能を有しておらず、分離機能層に強度を与えることができる。 Hereinafter, the "vertical" direction means the thickness direction of the composite semipermeable membrane, that is, the direction perpendicular to the membrane surface direction of the composite semipermeable membrane, and is the y-axis direction shown in FIGS. 1, 2, 3, and 4. Additionally, the separation functional layer is placed “on top” of the microporous support layer. In other words, the positive side of the y-axis is "up" and the negative side is "down." Note that the x-axis direction shown in FIGS. 1, 2, 3, and 4 is the membrane surface direction of the composite semipermeable membrane.
Themicroporous support layer 3 may be formed on the base material 2, and the composite semipermeable membrane 1 according to the embodiment of the present invention includes the base material 2 and the microporous support layer formed on the base material 2. It may have a support membrane including layer 3.
The separation functional layer substantially has separation performance. The microporous support layer has substantially no ability to separate ions, etc., and can provide strength to the separation functional layer.
微多孔性支持層３は、基材２上に形成されていてもよく、本発明の実施形態に係る複合半透膜１は、基材２と基材２上に形成された微多孔性支持層３とを含む支持膜を有していてもよい。
分離機能層は実質的に分離性能を有するものである。微多孔性支持層は実質的にイオン等の分離性能を有しておらず、分離機能層に強度を与えることができる。 Hereinafter, the "vertical" direction means the thickness direction of the composite semipermeable membrane, that is, the direction perpendicular to the membrane surface direction of the composite semipermeable membrane, and is the y-axis direction shown in FIGS. 1, 2, 3, and 4. Additionally, the separation functional layer is placed “on top” of the microporous support layer. In other words, the positive side of the y-axis is "up" and the negative side is "down." Note that the x-axis direction shown in FIGS. 1, 2, 3, and 4 is the membrane surface direction of the composite semipermeable membrane.
The
The separation functional layer substantially has separation performance. The microporous support layer has substantially no ability to separate ions, etc., and can provide strength to the separation functional layer.
（１－１）支持膜
支持膜は、基材と微多孔性支持層を備えてもよいし、または、支持膜は基材を有さず、微多孔性支持層のみで構成されていてもよい。すなわち、微多孔性支持層が支持膜であってもよい。 (1-1) Support membrane The support membrane may include a base material and a microporous support layer, or the support membrane may not have a base material and may be composed only of the microporous support layer. good. That is, the microporous support layer may be a support membrane.
支持膜は、基材と微多孔性支持層を備えてもよいし、または、支持膜は基材を有さず、微多孔性支持層のみで構成されていてもよい。すなわち、微多孔性支持層が支持膜であってもよい。 (1-1) Support membrane The support membrane may include a base material and a microporous support layer, or the support membrane may not have a base material and may be composed only of the microporous support layer. good. That is, the microporous support layer may be a support membrane.
基材としては、例えば、ポリエステル系重合体、ポリアミド系重合体、ポリオレフィン系重合体、これらの混合物又は共重合体からなる布帛等が挙げられる。中でも、機械的、熱的に安定性の高いポリエステル系重合体の布帛が好ましい。布帛の形態としては、長繊維不織布や短繊維不織布、さらには織編物を好ましく用いることができる。
Examples of the base material include fabrics made of polyester polymers, polyamide polymers, polyolefin polymers, and mixtures or copolymers thereof. Among these, a polyester polymer fabric with high mechanical and thermal stability is preferred. As the form of the fabric, long fiber nonwoven fabrics, short fiber nonwoven fabrics, and even woven and knitted fabrics can be preferably used.
微多孔性支持層は、一方の面から反対の面へ連通する多数の細孔を有する。微多孔性支持層における細孔の孔径や孔径分布に特に限定はない。例えば、微多孔性支持層は、均一な孔径からなる対称構造の細孔を有するか、又は一方の面からもう一方の面まで徐々に孔径が大きくなる非対称構造であり、かつ、孔径が小さい側の表面における孔径が０．１～１００ｎｍである構造の細孔を有することが好ましい。
The microporous support layer has a large number of pores that communicate from one side to the opposite side. There are no particular limitations on the pore size or pore size distribution of the pores in the microporous support layer. For example, the microporous support layer has pores with a symmetrical structure of uniform pore size, or has an asymmetric structure with pores that gradually increase in size from one side to the other, and the pores have a smaller pore size on the side. It is preferable to have pores having a structure in which the pore size on the surface is 0.1 to 100 nm.
微多孔性支持層の素材としては、ポリスルホン（以下、「ＰＳｆ」）、ポリエーテルスルホン、ポリアミド、ポリエステル、セルロース系ポリマー、ビニルポリマー、ポリフェニレンスルフィド、ポリフェニレンスルフィドスルホン、ポリフェニレンスルホン、ポリフェニレンオキシド等のホモポリマー又はコポリマーが挙げられ、これらを単独又はブレンドして使用することができる。ここでセルロース系ポリマーとしては、酢酸セルロース、硝酸セルロース等、ビニルポリマーとしてはポリエチレン、ポリプロピレン、ポリ塩化ビニル、ポリアクリロニトリル等が挙げられる。中でも、微多孔性支持層の素材としては、ＰＳｆ、ポリアミド、ポリエステル、酢酸セルロース、硝酸セルロース、ポリ塩化ビニル、ポリアクリロニトリル、ポリフェニレンスルフィド、ポリフェニレンスルフィドスルホン等のホモポリマー又はコポリマーが好ましく、酢酸セルロース、ＰＳｆ、ポリフェニレンスルフィドスルホン、ポリフェニレンスルホンがより好ましく、化学的、機械的、熱的に安定性が高く、成型が容易であることから、ＰＳｆが特に好ましい。
Materials for the microporous support layer include homopolymers such as polysulfone (hereinafter referred to as "PSf"), polyethersulfone, polyamide, polyester, cellulose polymer, vinyl polymer, polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfone, and polyphenylene oxide. or a copolymer, and these can be used alone or in a blend. Examples of the cellulose polymer include cellulose acetate and cellulose nitrate, and examples of the vinyl polymer include polyethylene, polypropylene, polyvinyl chloride, and polyacrylonitrile. Among these, as the material for the microporous support layer, homopolymers or copolymers such as PSf, polyamide, polyester, cellulose acetate, cellulose nitrate, polyvinyl chloride, polyacrylonitrile, polyphenylene sulfide, polyphenylene sulfide sulfone are preferable, and cellulose acetate, PSf , polyphenylene sulfide sulfone, and polyphenylene sulfone are more preferred, and PSf is particularly preferred because it has high chemical, mechanical, and thermal stability and is easy to mold.
ＰＳｆの重量平均分子量（以下、「Ｍｗ」）は、１００００～２０００００であることが好ましく、１５０００～１０００００であることがより好ましい。ＰＳｆのＭｗが１００００以上であることで、微多孔性支持層として好ましい機械的強度及び耐熱性を得ることができる。一方、ＰＳｆのＭｗが２０００００以下であることで、微多孔性支持層原液の粘度が適切な範囲となり、良好な成形性を実現することができる。重量平均分子量は、ゲル浸透クロマトグラフィー（ＧＰＣ）で測定されるポリスチレン換算の値をいう。
The weight average molecular weight (hereinafter referred to as "M w ") of PSf is preferably 10,000 to 200,000, more preferably 15,000 to 100,000. When the M w of PSf is 10,000 or more, it is possible to obtain preferable mechanical strength and heat resistance as a microporous support layer. On the other hand, when the M w of PSf is 200,000 or less, the viscosity of the microporous support layer stock solution falls within an appropriate range, and good moldability can be achieved. The weight average molecular weight refers to a polystyrene equivalent value measured by gel permeation chromatography (GPC).
基材と微多孔性支持層の厚みは、複合半透膜の強度及びそれをエレメントにしたときの充填密度に影響を与える。良好な機械的強度及び充填密度を得る観点から、基材と微多孔性支持層の厚みの合計は、３０～３００μｍであることが好ましく、１００～２２０μｍであることがより好ましい。また、微多孔性支持層の厚みは、２０～１００μｍであることが好ましい。なお、基材と微多孔性支持層の厚みは、断面観察で厚み方向に直交する方向（膜の面方向）に２０μｍ間隔で測定した、２０点の厚みの平均値を算出することで求めることができる。
The thickness of the base material and microporous support layer affects the strength of the composite semipermeable membrane and the packing density when it is used as an element. From the viewpoint of obtaining good mechanical strength and packing density, the total thickness of the base material and the microporous support layer is preferably 30 to 300 μm, more preferably 100 to 220 μm. Further, the thickness of the microporous support layer is preferably 20 to 100 μm. The thickness of the base material and the microporous support layer can be determined by calculating the average value of the thicknesses of 20 points measured at 20 μm intervals in the direction perpendicular to the thickness direction (in the plane direction of the membrane) during cross-sectional observation. Can be done.
（１－２）分離機能層
＜組成＞
本実施形態の複合半透膜における分離機能層は、溶質の分離機能を担う層であり、架橋芳香族ポリアミドを含有する。分離機能層は、架橋芳香族ポリアミドを主成分とすることが好ましい。 (1-2) Separation functional layer <Composition>
The separation functional layer in the composite semipermeable membrane of this embodiment is a layer responsible for the solute separation function, and contains crosslinked aromatic polyamide. The separation functional layer preferably contains crosslinked aromatic polyamide as a main component.
＜組成＞
本実施形態の複合半透膜における分離機能層は、溶質の分離機能を担う層であり、架橋芳香族ポリアミドを含有する。分離機能層は、架橋芳香族ポリアミドを主成分とすることが好ましい。 (1-2) Separation functional layer <Composition>
The separation functional layer in the composite semipermeable membrane of this embodiment is a layer responsible for the solute separation function, and contains crosslinked aromatic polyamide. The separation functional layer preferably contains crosslinked aromatic polyamide as a main component.
「架橋芳香族ポリアミドを主成分とする」とは、分離機能層に占める架橋芳香族ポリアミドの質量割合が５０質量％以上であることを意味する。分離機能層に占める架橋芳香族ポリアミドの質量割合は、８０質量％以上であることが好ましく、９０質量％以上であることがより好ましく、分離機能層は実質的に架橋芳香族ポリアミドのみで構成されていることがさらに好ましい。分離機能層が実質的に架橋芳香族ポリアミドのみで構成されるとは、分離機能層に占める架橋芳香族ポリアミドの質量割合が９９質量％以上であることを意図する。
"Mainly composed of crosslinked aromatic polyamide" means that the mass proportion of crosslinked aromatic polyamide in the separation functional layer is 50% by mass or more. The mass proportion of the crosslinked aromatic polyamide in the separation functional layer is preferably 80% by mass or more, more preferably 90% by mass or more, and the separation functional layer is substantially composed only of the crosslinked aromatic polyamide. It is more preferable that the When the separation functional layer is substantially composed only of crosslinked aromatic polyamide, it is intended that the mass proportion of the crosslinked aromatic polyamide in the separation functional layer is 99% by mass or more.
複合半透膜の分離機能層における架橋芳香族ポリアミドの割合は、核磁気共鳴測定（以下、「ＮＭＲ測定」）により算出できる。例えば、複合半透膜から基材を物理的に剥離させ、微多孔性支持層と分離機能層を回収する。回収した微多孔性支持層と分離機能層を２５℃で２４時間静置し、乾燥させた後、ジクロロメタンの入ったビーカー内に少量ずつ加えて撹拌し、微多孔性支持層を構成するポリマーを溶解する。ビーカー内の不溶物を濾紙で回収し、得られた不溶物をジクロロメタンの入ったビーカー内に入れ撹拌し、ビーカー内の不溶物を回収する作業を、ジクロロメタン溶液中に微多孔性支持層を形成するポリマーの溶出が検出できなくなるまで繰り返す。回収した不溶物を真空乾燥機で乾燥させ、残存するジクロロメタンを除去し、得られた不溶物を凍結粉砕により粉末状の試料として単離する。この粉末状の試料、すなわち分離機能層を、高濃度及び高温の水酸化ナトリウム水溶液中で固形分が溶解するまで浸漬することにより、分離機能層をアルカリ加水分解し、得られた溶液の１Ｈ－ＮＭＲ測定を行い、得られたピークの面積からモノマーを定量することが可能である。芳香環を有するモノマーの質量基準の割合が架橋芳香族ポリアミドの質量基準の割合にあたる。
The proportion of crosslinked aromatic polyamide in the separation functional layer of the composite semipermeable membrane can be calculated by nuclear magnetic resonance measurement (hereinafter referred to as "NMR measurement"). For example, the base material is physically peeled off from the composite semipermeable membrane, and the microporous support layer and separation functional layer are recovered. The recovered microporous support layer and separation functional layer were allowed to stand at 25°C for 24 hours, dried, and then added little by little into a beaker containing dichloromethane and stirred to dissolve the polymer constituting the microporous support layer. dissolve. The insoluble matter in the beaker is collected with a filter paper, the obtained insoluble matter is placed in a beaker containing dichloromethane and stirred, and the process of collecting the insoluble matter in the beaker is performed to form a microporous support layer in the dichloromethane solution. Repeat until the elution of the desired polymer is no longer detectable. The collected insoluble matter is dried in a vacuum dryer to remove remaining dichloromethane, and the obtained insoluble matter is isolated as a powder sample by freeze-pulverization. This powdered sample, that is, the separation functional layer, is immersed in a high-concentration and high-temperature sodium hydroxide aqueous solution until the solid content is dissolved, thereby alkaline hydrolyzing the separation functional layer, and 1 H of the obtained solution. - It is possible to perform NMR measurement and quantify the monomer from the area of the obtained peak. The mass-based proportion of the monomer having an aromatic ring corresponds to the mass-based proportion of the crosslinked aromatic polyamide.
架橋芳香族ポリアミドとしては、アラミド系の化合物が挙げられ、その他にもアラミド系の化合物の分子構造内に芳香族以外の部位を含んでもよい。中でも、剛直性、化学的安定性、及び／又は操作圧力に対する耐久性の点から架橋全芳香族ポリアミドであることがより好ましい。架橋芳香族ポリアミドは、多官能芳香族アミンと多官能芳香族酸ハロゲン化物との界面重縮合により形成することができる。ここで、架橋構造となるために、多官能芳香族アミン及び多官能芳香族酸ハロゲン化物の少なくとも一方は３官能以上の化合物を含む。
Examples of the crosslinked aromatic polyamide include aramid compounds, and the aramid compounds may also contain non-aromatic moieties in their molecular structure. Among these, crosslinked wholly aromatic polyamide is more preferable from the viewpoint of rigidity, chemical stability, and/or durability against operating pressure. A crosslinked aromatic polyamide can be formed by interfacial polycondensation of a polyfunctional aromatic amine and a polyfunctional aromatic acid halide. Here, in order to form a crosslinked structure, at least one of the polyfunctional aromatic amine and the polyfunctional aromatic acid halide contains a trifunctional or higher functional compound.
「多官能芳香族アミン」とは、一分子中に第一級アミノ基及び第二級アミノ基のうち少なくとも一方のアミノ基を２個以上有し、かつ、アミノ基のうち少なくとも１つは第一級アミノ基である芳香族アミンを意味する。
A "polyfunctional aromatic amine" has two or more amino groups of at least one of a primary amino group and a secondary amino group in one molecule, and at least one of the amino groups is a secondary amino group. It means an aromatic amine which is a primary amino group.
多官能芳香族アミンとしては、例えば、ｏ－フェニレンジアミン、ｍ－フェニレンジアミン（以下「ｍ－ＰＤＡ」）、ｐ－フェニレンジアミン、ｏ－キシリレンジアミン、ｍ－キシリレンジアミン、ｐ－キシリレンジアミン、ｏ－ジアミノピリジン、ｍ－ジアミノピリジン、ｐ－ジアミノピリジン等の２個のアミノ基がオルト位やメタ位、パラ位のいずれかの位置関係で芳香環に結合した多官能芳香族アミン、１，３，５－トリアミノベンゼン、１，２，４－トリアミノベンゼン、３，５－ジアミノ安息香酸、３－アミノベンジルアミン、４－アミノベンジルアミン等の多官能芳香族アミン等が挙げられる。
Examples of polyfunctional aromatic amines include o-phenylenediamine, m-phenylenediamine (hereinafter referred to as "m-PDA"), p-phenylenediamine, o-xylylenediamine, m-xylylenediamine, and p-xylylenediamine. , o-diaminopyridine, m-diaminopyridine, p-diaminopyridine, etc., a polyfunctional aromatic amine in which two amino groups are bonded to an aromatic ring in any of the ortho, meta, and para positions, 1 , 3,5-triaminobenzene, 1,2,4-triaminobenzene, 3,5-diaminobenzoic acid, 3-aminobenzylamine, 4-aminobenzylamine, and other polyfunctional aromatic amines.
中でも、膜の選択分離性や透過性、耐熱性を向上する観点から、ｍ－ＰＤＡ、ｐ－フェニレンジアミン又は１，３，５－トリアミノベンゼンが好適に用いられる。中でも、入手の容易性や取り扱いのしやすさから、ｍ－ＰＤＡを用いることがより好ましい。これらの多官能芳香族アミンは、単独で用いてもよいし、２種以上を併用してもよい。
Among these, m-PDA, p-phenylenediamine, or 1,3,5-triaminobenzene is preferably used from the viewpoint of improving the selective separation property, permeability, and heat resistance of the membrane. Among these, it is more preferable to use m-PDA because of its ease of availability and handling. These polyfunctional aromatic amines may be used alone or in combination of two or more.
「多官能芳香族酸ハロゲン化物」とは、一分子中に少なくとも２個のハロゲン化カルボニル基を有する芳香族酸ハロゲン化物を意味する。例えば、３官能酸ハロゲン化物としては、トリメシン酸クロリド等が挙げられ、２官能酸ハロゲン化物としては、ビフェニルジカルボン酸ジクロリド、アゾベンゼンジカルボン酸ジクロリド、テレフタル酸クロリド、イソフタル酸クロリド、ナフタレンジカルボン酸クロリド等が挙げられる。酸ハロゲン化物の中でも、酸塩化物が好ましく、特に経済性、入手の容易さ、取り扱い易さ及び反応性の容易さ等の点から、１，３，５－ベンゼントリカルボン酸の酸ハロゲン化物であるトリメシン酸クロリド（以下、「ＴＭＣ」）が好ましい。
"Polyfunctional aromatic acid halide" means an aromatic acid halide having at least two halogenated carbonyl groups in one molecule. For example, examples of trifunctional acid halides include trimesic acid chloride, and examples of difunctional acid halides include biphenyldicarboxylic acid dichloride, azobenzenedicarboxylic acid dichloride, terephthalic acid chloride, isophthalic acid chloride, naphthalenedicarboxylic acid chloride, etc. Can be mentioned. Among the acid halides, acid chlorides are preferred, particularly acid halides of 1,3,5-benzenetricarboxylic acid from the viewpoint of economy, ease of availability, ease of handling, and ease of reactivity. Trimesic acid chloride (hereinafter referred to as "TMC") is preferred.
多官能芳香族アミンとの反応性を考慮すると、多官能芳香族酸ハロゲン化物は多官能芳香族酸塩化物であることが好ましく、また、膜の選択分離性、耐熱性を向上する観点から、一分子中に２～４個の塩化カルボニル基を有する多官能芳香族酸塩化物であることが好ましい。
Considering the reactivity with the polyfunctional aromatic amine, the polyfunctional aromatic acid halide is preferably a polyfunctional aromatic acid chloride, and from the viewpoint of improving the selective separation property and heat resistance of the membrane, A polyfunctional aromatic acid chloride having 2 to 4 carbonyl chloride groups in one molecule is preferred.
架橋芳香族ポリアミドの一例として、トリメシン酸クロリドとｍ－フェニレンジアミンの重合物であるポリアミドが挙げられる。
An example of the crosslinked aromatic polyamide is a polyamide that is a polymer of trimesic acid chloride and m-phenylenediamine.
＜薄膜＞
本実施形態の複合半透膜における分離機能層は薄膜で構成される。分離機能層の組成についての上記説明は、薄膜にも当てはまる。つまり、上記説明において「分離機能層」を「薄膜」と読み替えてもよい。 <Thin film>
The separation functional layer in the composite semipermeable membrane of this embodiment is composed of a thin film. The above explanation regarding the composition of the separation functional layer also applies to thin films. That is, in the above description, "separation functional layer" may be read as "thin film".
本実施形態の複合半透膜における分離機能層は薄膜で構成される。分離機能層の組成についての上記説明は、薄膜にも当てはまる。つまり、上記説明において「分離機能層」を「薄膜」と読み替えてもよい。 <Thin film>
The separation functional layer in the composite semipermeable membrane of this embodiment is composed of a thin film. The above explanation regarding the composition of the separation functional layer also applies to thin films. That is, in the above description, "separation functional layer" may be read as "thin film".
薄膜の形状や厚みは、分離性能及び透過性能に影響を与える。薄膜は、図２に示すように、複数の突起が繰り返し現れるひだ構造を構成する。図２は、複合半透膜の膜面方向に垂直な断面における、薄膜で構成される突起の構造を示す模式図である。
The shape and thickness of the thin film affect separation performance and permeation performance. As shown in FIG. 2, the thin film forms a pleated structure in which a plurality of protrusions appear repeatedly. FIG. 2 is a schematic diagram showing the structure of a protrusion made of a thin film in a cross section perpendicular to the membrane surface direction of a composite semipermeable membrane.
図３は、複合半透膜の膜面方向に垂直な断面における、薄膜で構成される突起の構造を示す模式図であり、図２よりも突起を拡大して示した図である。
突起とは、分離機能層の薄膜５が構成する構造であり、薄膜５において、ｘ方向にて互いに隣接する、微多孔性支持層３に向かって凸形状の２つの部分（凹部と言い換えてもよい）の頂点の間（凸部６）を指す（図３）。図３では、突起（凸部６）の両端（凹部の頂点）の一方が微多孔性支持層３の表面から離れ、他方が接触している例を示している。なお、突起の両端が微多孔性支持層３に接していてもよいし、両端が微多孔性支持層３から離れていてもよい。 FIG. 3 is a schematic diagram showing the structure of a protrusion made of a thin film in a cross section perpendicular to the membrane surface direction of a composite semipermeable membrane, and is a diagram showing the protrusion more enlarged than in FIG. 2.
A protrusion is a structure formed by thethin film 5 of the separation functional layer, and is defined by two convex portions (also referred to as recesses) that are adjacent to each other in the x direction toward the microporous support layer 3 in the thin film 5. (Fig. 3). FIG. 3 shows an example in which one of both ends (vertex of the recess) of the protrusion (convex part 6) is separated from the surface of the microporous support layer 3, and the other is in contact with the surface. Note that both ends of the protrusion may be in contact with the microporous support layer 3, or both ends may be separated from the microporous support layer 3.
突起とは、分離機能層の薄膜５が構成する構造であり、薄膜５において、ｘ方向にて互いに隣接する、微多孔性支持層３に向かって凸形状の２つの部分（凹部と言い換えてもよい）の頂点の間（凸部６）を指す（図３）。図３では、突起（凸部６）の両端（凹部の頂点）の一方が微多孔性支持層３の表面から離れ、他方が接触している例を示している。なお、突起の両端が微多孔性支持層３に接していてもよいし、両端が微多孔性支持層３から離れていてもよい。 FIG. 3 is a schematic diagram showing the structure of a protrusion made of a thin film in a cross section perpendicular to the membrane surface direction of a composite semipermeable membrane, and is a diagram showing the protrusion more enlarged than in FIG. 2.
A protrusion is a structure formed by the
「突起の見かけ高さ」とは、図４に示すように、微多孔性支持層３の表面を基準とした突起（凸部６）の高さ、すなわち微多孔性支持層３の表面から突起（凸部６）の頂点までの距離である。突起の見かけ高さＰａｈにおいて、突起（凸部６）の頂点を通る、ｙ軸方向にて、微多孔性支持層３の表面の位置が高さ０％であり、突起（凸部６）の頂点が高さの１００％である。「突起の見かけ高さ」における「突起の頂点」とは、突起内で微多孔性支持層からの距離が最も遠い位置を意味する。
As shown in FIG. This is the distance to the apex of (the convex portion 6). At the apparent height Pah of the protrusion, the height of the surface of the microporous support layer 3 is 0% in the y-axis direction passing through the apex of the protrusion (protrusion 6), and the height of the protrusion (protrusion 6) is 0%. The apex is 100% of the height. The "apex of the protrusion" in the "apparent height of the protrusion" means the farthest position within the protrusion from the microporous support layer.
薄膜の厚み測定等に用いる１０点平均面粗さについて、以下に説明する。
複合半透膜の膜面方向に垂直で、かつ膜面方向の長さが２．０μｍである断面の画像を、以下の手順で得る。
複合半透膜の膜面方向に垂直な断面を有する試料切片は、凍結超薄切片法にて得ることができる。また、断面観察は走査電子顕微鏡（ＳＥＭ、ＦＥ－ＳＥＭ）、透過型電子顕微鏡（ＴＥＭ）、走査透過電子顕微鏡（ＳＴＥＭ）等の電子顕微鏡により行うことができる。観察倍率は１０，０００～１００，０００倍が好ましい。得られた断面画像には、図２に示すように、分離機能層における薄膜５の表面が曲線として表れる。この曲線について、ＪＩＳ Ｂ ０６０１（ＩＳＯ４２８７：１９９７）に基づき定義される粗さ曲線を求める。上記試料切片の断面から、上記粗さ曲線の平均線Ａ（以下、「平均線Ａ」とも称する。）の方向に基準長さＬ（２．０μｍ）の幅で断面画像を抜き取る。
「平均線」とは、ＪＩＳ Ｂ ０６０１（ＩＳＯ４２８７：１９９７）に基づき定義され、測定範囲において、平均線と粗さ曲線とで囲まれる領域の面積の合計が平均線の上下で等しくなるように描かれる直線である。 The 10-point average surface roughness used for thin film thickness measurement etc. will be explained below.
An image of a cross section of the composite semipermeable membrane perpendicular to the membrane surface direction and having a length of 2.0 μm in the membrane surface direction is obtained by the following procedure.
A sample section having a cross section perpendicular to the membrane surface direction of the composite semipermeable membrane can be obtained by a frozen ultrathin section method. Further, cross-sectional observation can be performed using an electron microscope such as a scanning electron microscope (SEM, FE-SEM), a transmission electron microscope (TEM), or a scanning transmission electron microscope (STEM). The observation magnification is preferably 10,000 to 100,000 times. In the obtained cross-sectional image, as shown in FIG. 2, the surface of thethin film 5 in the separation functional layer appears as a curve. For this curve, a roughness curve defined based on JIS B 0601 (ISO4287:1997) is determined. A cross-sectional image with a width of a reference length L (2.0 μm) is extracted from the cross section of the sample section in the direction of the average line A (hereinafter also referred to as "average line A") of the roughness curve.
The "average line" is defined based on JIS B 0601 (ISO4287:1997), and is drawn so that the total area of the area surrounded by the average line and the roughness curve is equal above and below the average line in the measurement range. It is a straight line.
複合半透膜の膜面方向に垂直で、かつ膜面方向の長さが２．０μｍである断面の画像を、以下の手順で得る。
複合半透膜の膜面方向に垂直な断面を有する試料切片は、凍結超薄切片法にて得ることができる。また、断面観察は走査電子顕微鏡（ＳＥＭ、ＦＥ－ＳＥＭ）、透過型電子顕微鏡（ＴＥＭ）、走査透過電子顕微鏡（ＳＴＥＭ）等の電子顕微鏡により行うことができる。観察倍率は１０，０００～１００，０００倍が好ましい。得られた断面画像には、図２に示すように、分離機能層における薄膜５の表面が曲線として表れる。この曲線について、ＪＩＳ Ｂ ０６０１（ＩＳＯ４２８７：１９９７）に基づき定義される粗さ曲線を求める。上記試料切片の断面から、上記粗さ曲線の平均線Ａ（以下、「平均線Ａ」とも称する。）の方向に基準長さＬ（２．０μｍ）の幅で断面画像を抜き取る。
「平均線」とは、ＪＩＳ Ｂ ０６０１（ＩＳＯ４２８７：１９９７）に基づき定義され、測定範囲において、平均線と粗さ曲線とで囲まれる領域の面積の合計が平均線の上下で等しくなるように描かれる直線である。 The 10-point average surface roughness used for thin film thickness measurement etc. will be explained below.
An image of a cross section of the composite semipermeable membrane perpendicular to the membrane surface direction and having a length of 2.0 μm in the membrane surface direction is obtained by the following procedure.
A sample section having a cross section perpendicular to the membrane surface direction of the composite semipermeable membrane can be obtained by a frozen ultrathin section method. Further, cross-sectional observation can be performed using an electron microscope such as a scanning electron microscope (SEM, FE-SEM), a transmission electron microscope (TEM), or a scanning transmission electron microscope (STEM). The observation magnification is preferably 10,000 to 100,000 times. In the obtained cross-sectional image, as shown in FIG. 2, the surface of the
The "average line" is defined based on JIS B 0601 (ISO4287:1997), and is drawn so that the total area of the area surrounded by the average line and the roughness curve is equal above and below the average line in the measurement range. It is a straight line.
このように抜き取られた断面画像において、平均線Ａから、粗さ曲線の最も高い山頂から５番目までの山頂の標高（平均線Ａから最も高い山頂から５番目までの山頂の標高Ｙｐ１～５）の絶対値の平均値と、最も低い谷底から５番目までの谷底の標高（平均線Ａから最も低い谷底から５番目までの谷底の標高Ｙｖ１～５）の絶対値の平均値との和を求め、この値をナノメートル（ｎｍ）で表したものが、その断面画像における１０点平均面粗さである（図２）。
無作為に選択した１０枚の断面画像について同様の測定を行い、得られた１０点平均面粗さの平均値を、複合半透膜の１０点平均面粗さとする。 In the cross-sectional image extracted in this way, the altitudes of the highest to fifth peaks on the roughness curve from the average line A (elevations of the highest to fifth peaks from the average line A, Yp1 to 5). Find the sum of the average absolute value of and the average absolute value of the elevations of the fifth valley bottom from the lowest valley bottom (elevations Yv1 to 5 of the fifth valley bottom from the lowest valley bottom from the average line A). , this value expressed in nanometers (nm) is the 10-point average surface roughness in the cross-sectional image (FIG. 2).
Similar measurements are performed on 10 randomly selected cross-sectional images, and the average value of the obtained 10-point average surface roughness is defined as the 10-point average surface roughness of the composite semipermeable membrane.
無作為に選択した１０枚の断面画像について同様の測定を行い、得られた１０点平均面粗さの平均値を、複合半透膜の１０点平均面粗さとする。 In the cross-sectional image extracted in this way, the altitudes of the highest to fifth peaks on the roughness curve from the average line A (elevations of the highest to fifth peaks from the average line A, Yp1 to 5). Find the sum of the average absolute value of and the average absolute value of the elevations of the fifth valley bottom from the lowest valley bottom (elevations Yv1 to 5 of the fifth valley bottom from the lowest valley bottom from the average line A). , this value expressed in nanometers (nm) is the 10-point average surface roughness in the cross-sectional image (FIG. 2).
Similar measurements are performed on 10 randomly selected cross-sectional images, and the average value of the obtained 10-point average surface roughness is defined as the 10-point average surface roughness of the composite semipermeable membrane.
「突起の高さ」は次のようにして算出できる。上述のようにして無作為に選択した１０枚の断面画像から抜き取られた幅２．０μｍの断面画像において、突起の見かけ高さＰａｈが上述の１０点平均面粗さの５分の１以上である突起について、複合半透膜の膜面方向における上記突起の両端と、平均線Ａとの、距離ｄ１及びｄ２を測定する。距離ｄ１及びｄ２の平均値ｄを算出する。
ここで、距離ｄ１及びｄ２は、平均線Ａから突起の両端の間の、複合半透膜の膜面方向に垂直な方向の距離である。また、上記突起の両端とは、薄膜において、互いに隣接する、微多孔性支持層に向かって凸形状の２つの部分の各頂点である。すなわち、上記突起の両端は、突起を挟む２つの凹部の各頂点である。 The "height of the protrusion" can be calculated as follows. In a cross-sectional image with a width of 2.0 μm extracted from 10 cross-sectional images randomly selected as described above, the apparent height Pah of the protrusion is one-fifth or more of the 10-point average surface roughness described above. Regarding a certain protrusion, the distances d1 and d2 between both ends of the protrusion and the average line A in the membrane surface direction of the composite semipermeable membrane are measured. An average value d of distances d1 and d2 is calculated.
Here, the distances d1 and d2 are distances from the average line A to both ends of the protrusions in a direction perpendicular to the membrane surface direction of the composite semipermeable membrane. Further, both ends of the protrusion are the vertices of two adjacent parts of the thin film that are convex toward the microporous support layer. That is, both ends of the protrusion are the vertices of two recesses sandwiching the protrusion.
ここで、距離ｄ１及びｄ２は、平均線Ａから突起の両端の間の、複合半透膜の膜面方向に垂直な方向の距離である。また、上記突起の両端とは、薄膜において、互いに隣接する、微多孔性支持層に向かって凸形状の２つの部分の各頂点である。すなわち、上記突起の両端は、突起を挟む２つの凹部の各頂点である。 The "height of the protrusion" can be calculated as follows. In a cross-sectional image with a width of 2.0 μm extracted from 10 cross-sectional images randomly selected as described above, the apparent height Pah of the protrusion is one-fifth or more of the 10-point average surface roughness described above. Regarding a certain protrusion, the distances d1 and d2 between both ends of the protrusion and the average line A in the membrane surface direction of the composite semipermeable membrane are measured. An average value d of distances d1 and d2 is calculated.
Here, the distances d1 and d2 are distances from the average line A to both ends of the protrusions in a direction perpendicular to the membrane surface direction of the composite semipermeable membrane. Further, both ends of the protrusion are the vertices of two adjacent parts of the thin film that are convex toward the microporous support layer. That is, both ends of the protrusion are the vertices of two recesses sandwiching the protrusion.
すなわち、図３に示すように、突起（凸部６）の両端の深さ、すなわち平均線Ａから突起左側の凹部の頂点までの距離ｄ１及び平均線Ａから突起右側の凹部の頂点までの距離ｄ２の平均ｄと、平均線Ａから突起の頂点までの距離ｈの和が、突起の高さＰｈとして算出される。複合半透膜の膜面方向に垂直な方向において、平均線Ａから微多孔性支持層に向かう距離がｄである位置が高さ０％であり、突起の頂点が高さの１００％である。「突起の高さ」における「突起の頂点」とは、突起内で前述の粗さ曲線の平均線からの距離が最も遠い位置を意味する。
That is, as shown in FIG. 3, the depth of both ends of the protrusion (protrusion 6), that is, the distance d1 from the average line A to the apex of the recess on the left side of the protrusion, and the distance from the average line A to the apex of the recess on the right side of the protrusion. The sum of the average d of d2 and the distance h from the average line A to the apex of the protrusion is calculated as the height Ph of the protrusion. In the direction perpendicular to the membrane surface direction of the composite semipermeable membrane, the position where the distance from the average line A toward the microporous support layer is d is 0% of the height, and the apex of the protrusion is 100% of the height. . The "vertex of the protrusion" in "height of the protrusion" means the position within the protrusion that is farthest from the average line of the roughness curve.
突起の高さは、複合半透膜の透水性を十分とする観点から、７０ｎｍ以上が好ましく、９０ｎｍ以上がより好ましい。また、高圧運転する際の突起の変形を抑制し、安定した膜性能を得ることができる観点から、突起の高さは、１０００ｎｍ以下が好ましく、８００ｎｍ以下がより好ましく、４００ｎｍ以下がさらに好ましい。すなわち、突起の高さは７０ｎｍ～１０００ｎｍが好ましい。突起の高さは、例えば、多官能芳香族アミン水溶液における多官能芳香族アミン濃度や、多官能芳香族アミン水溶液を接触させた微多孔性支持層と多官能芳香族酸ハロゲン化物の有機溶媒溶液を接触させる温度を変更することで調整できる。
The height of the protrusion is preferably 70 nm or more, more preferably 90 nm or more, from the viewpoint of ensuring sufficient water permeability of the composite semipermeable membrane. Further, from the viewpoint of suppressing deformation of the protrusions during high-pressure operation and obtaining stable film performance, the height of the protrusions is preferably 1000 nm or less, more preferably 800 nm or less, and even more preferably 400 nm or less. That is, the height of the protrusion is preferably 70 nm to 1000 nm. The height of the projections can be determined, for example, by the concentration of a polyfunctional aromatic amine in an aqueous solution of a polyfunctional aromatic amine, or the difference between a microporous support layer in contact with an aqueous solution of a polyfunctional aromatic amine and an organic solvent solution of a polyfunctional aromatic acid halide. It can be adjusted by changing the temperature of contact.
薄膜の厚みは、薄膜の表面上のある点から、反対側の表面への最短距離を意味する。薄膜の厚みは、透過型電子顕微鏡（ＴＥＭ）で、複合半透膜の膜面方向に垂直な、突起の断面を撮影し、断面写真を画像解析ソフトに読み込んで解析を行うことで測定できる。観察倍率は、薄膜の厚みにより適宜決定すればよい。例えば、薄膜の断面形状が観察でき、かつ、測定が局所的にならないようにするため、薄膜の厚みが１０～１００ｎｍ程度であれば、観察倍率を５～１０万倍とするとよい。なお、薄膜厚みの測定の対象とする突起は、１０点平均面粗さの５分の１以上の高さを有する突起から無作為に選択する。
Thickness of a thin film means the shortest distance from a point on the surface of the thin film to the opposite surface. The thickness of the thin film can be measured by photographing a cross section of the protrusion perpendicular to the membrane surface direction of the composite semipermeable membrane using a transmission electron microscope (TEM), and importing the cross-sectional photograph into image analysis software for analysis. The observation magnification may be appropriately determined depending on the thickness of the thin film. For example, if the thickness of the thin film is approximately 10 to 100 nm, the observation magnification may be set to 50,000 to 100,000 times so that the cross-sectional shape of the thin film can be observed and the measurement is not localized. Note that the protrusions to be measured for the thin film thickness are randomly selected from protrusions having a height of one-fifth or more of the 10-point average surface roughness.
突起を構成する薄膜の厚み、及び突起の高さの２～２５％の範囲における薄膜の平均厚みＴ２５に対する、突起の高さ７５～９８％の範囲における薄膜の平均厚みＴ９８の比（Ｔ９８／Ｔ２５）は次のようにして算出できる。
The thickness of the thin film constituting the protrusion, and the ratio of the average thickness T98 of the thin film in the range of 75 to 98% of the height of the protrusion to the average thickness T25 of the thin film in the range of 2 to 25% of the height of the protrusion (T98/T25 ) can be calculated as follows.
ここで、突起の高さ７５～９８％の範囲を「突起上部」、突起の高さの２～２５％の範囲を「突起下部」とも表記する。
Here, the range of 75 to 98% of the height of the protrusion is also referred to as the "upper part of the protrusion", and the range of 2 to 25% of the height of the protrusion is also referred to as the "lower part of the protrusion".
図３に示すように、ｘ軸方向における突起（凸部６）の両隣の凹部の深さｄ１及びｄ２の平均値ｄを算出する。平均線Ａの下側（微多孔性支持層３側）で、ｙ軸方向に、平均線Ａからの距離がｄである位置Ｚを高さ０％、突起の頂点の位置Ｂを高さ１００％とする。その突起を構成する薄膜の厚みを、突起上部及び突起下部で、それぞれ無作為に１０カ所ずつ測定する。同様の測定を、突起の高さが１０点平均面粗さの５分の１以上である５つの突起について行う。突起下部における薄膜厚みの５０点の値について、相加平均値を算出する。この値をその複合半透膜における薄膜が構成する突起下部の平均厚みＴ２５とする。突起上部の範囲における薄膜厚みについても同様に相加平均を算出し、これを薄膜が構成する突起上部の平均厚みＴ９８とする。突起の物理的外力への耐久性を向上させ、変形を抑制することで透水性及び塩除去率を維持できる観点及び良好な透水性を確保する観点から、突起下部の平均厚みＴ２５は、１３～２４ｎｍであることが好ましい。突起を構成する薄膜の厚みは、多官能芳香族アミン水溶液を接触させた微多孔性支持層と多官能芳香族酸ハロゲン化物の有機溶媒溶液を接触させる温度や加熱温度、後述の架橋芳香族ポリアミドを含有する層にアミド基を含む化合物を含有する溶液を接触させる工程により調整できる。
As shown in FIG. 3, the average value d of the depths d1 and d2 of the recesses on both sides of the protrusion (protrusion 6) in the x-axis direction is calculated. Below the average line A (on the side of the microporous support layer 3), in the y-axis direction, position Z at a distance of d from the average line A has a height of 0%, and position B of the apex of the protrusion has a height of 100%. %. The thickness of the thin film constituting the protrusion is measured at 10 random locations on each of the upper and lower parts of the protrusion. Similar measurements are performed on five protrusions whose height is one-fifth or more of the 10-point average surface roughness. The arithmetic mean value is calculated for the 50 points of the thin film thickness at the lower part of the protrusion. This value is defined as the average thickness T25 of the lower part of the protrusion formed by the thin film in the composite semipermeable membrane. The arithmetic mean of the thickness of the thin film in the area above the protrusion is similarly calculated, and this is set as the average thickness T98 of the upper part of the protrusion constituted by the thin film. From the viewpoint of improving the durability of the protrusion against physical external forces and maintaining water permeability and salt removal rate by suppressing deformation, and from the viewpoint of ensuring good water permeability, the average thickness T25 of the lower part of the protrusion is set to 13 to 13. Preferably, it is 24 nm. The thickness of the thin film constituting the protrusions is determined by the temperature and heating temperature at which the microporous support layer in which the polyfunctional aromatic amine aqueous solution is brought into contact with the organic solvent solution of the polyfunctional aromatic acid halide, and the crosslinked aromatic polyamide described below. It can be adjusted by a step of bringing a solution containing a compound containing an amide group into contact with the layer containing the amide group.
突起下部の平均厚みＴ２５に対する突起上部の平均厚みＴ９８の比（Ｔ９８／Ｔ２５）は０．９５以下であることが好ましく、０．７０～０．９２であることがより好ましい。複合半透膜は一般的に重ねて使用され、膜の間には流路材が挿入される。Ｔ９８／Ｔ２５がこの範囲を満たすことで、突起上部では薄膜が薄く柔軟で、突起下部は厚く丈夫となるため、使用中に突起が流路材又は他の複合半透膜と擦れた場合でも、突起下部に力が分散し、損傷を低減することができ、塩除去率を維持することができる。
The ratio (T98/T25) of the average thickness T98 of the upper part of the protrusion to the average thickness T25 of the lower part of the protrusion is preferably 0.95 or less, and more preferably 0.70 to 0.92. Composite semipermeable membranes are generally used in layers, with a channel material inserted between the membranes. When T98/T25 satisfies this range, the thin film is thin and flexible at the top of the protrusion, and thick and strong at the bottom of the protrusion, so even if the protrusion rubs against the channel material or other composite semipermeable membrane during use, The force is distributed under the protrusion, reducing damage and maintaining the salt removal rate.
分離機能層には、多官能芳香族アミンと多官能芳香族酸ハロゲン化物の重合に由来するアミド基、未反応官能基に由来するアミノ基とカルボキシ基が存在することがあり、突起には多数の酸素原子（以下「Ｏ」）及び窒素原子（以下「Ｎ」）が存在する。突起における窒素原子に対する酸素原子の比（Ｏ／Ｎ比）は、ＴＥＭ観察時に電子エネルギー損失分光法（ＥＥＬＳ：Ｅｌｅｃｔｒｏｎ Ｅｎｅｒｇｙ－Ｌｏｓｓ Ｓｐｅｃｔｒｏｓｃｏｐｙ）を用いて解析することによって得られる。本発明者らは、突起の見かけ高さＰａｈが上述の１０点平均面粗さの５分の１以上である突起について、突起の見かけ高さの２～２５％の範囲におけるＯ／Ｎ比の平均値をｘ、突起の見かけ高さ７５～９８％の範囲におけるＯ／Ｎ比の平均値をｙとしたとき、ｙ／ｘ≧１．３を満たす複合半透膜において、特に高い透水性と除去性を有し、さらに塩素との接触後も高い除去性を示すことを見出した。ｘ、ｙは多官能芳香族アミンや多官能芳香族酸ハロゲン化物等のモノマー濃度や界面重縮合で用いてもよい添加剤、後述の架橋芳香族ポリアミドを含有する上記層にアミド基を含む化合物を含有する溶液を接触させる工程の導入により調整できる。
The separation functional layer may contain amide groups derived from the polymerization of polyfunctional aromatic amines and polyfunctional aromatic acid halides, and amino groups and carboxy groups derived from unreacted functional groups. There are oxygen atoms (hereinafter referred to as "O") and nitrogen atoms (hereinafter referred to as "N"). The ratio of oxygen atoms to nitrogen atoms (O/N ratio) in the protrusion is obtained by analyzing using electron energy-loss spectroscopy (EELS) during TEM observation. The present inventors investigated the O/N ratio in the range of 2 to 25% of the apparent height of the protrusion for protrusions whose apparent height Pah is one-fifth or more of the above-mentioned 10-point average surface roughness. When the average value is x and the average value of the O/N ratio in the range of 75 to 98% of the apparent height of the protrusions is y, a composite semipermeable membrane that satisfies y/x≧1.3 has particularly high water permeability. It has been found that it has removability and also shows high removability even after contact with chlorine. x and y are monomer concentrations such as polyfunctional aromatic amines and polyfunctional aromatic acid halides, additives that may be used in interfacial polycondensation, and compounds containing amide groups in the layer containing the crosslinked aromatic polyamide described below. This can be adjusted by introducing a step of contacting a solution containing .
架橋芳香族ポリアミドの主骨格繰り返し単位におけるＯ／Ｎ比は、突起の上の方、下の方のいずれにおいても値は同じであるため、突起におけるＯ／Ｎ比は実質的に（架橋芳香族ポリアミドの末端に存在するカルボキシ基）／（架橋芳香族ポリアミドの末端に存在するアミノ基）に比例する。末端官能基は複合半透膜の除去性能や透水性にも影響を与える。アミノ基密度が高い領域においては、分離機能層は疎な構造となり、透水抵抗が低いため透水性は高まるが、溶質の除去性能は不十分である。一方、アミノ基密度が低い領域においては、分離機能層は密な構造となり、透水抵抗が高いため透水性は低いが、溶質の除去性能が高まる。突起内にＯ／Ｎ比傾斜構造を付与し、小孔径部分と高荷電部分を作ることで、特に高い透水性と除去性能を両立することができる。ここで、Ｏ／Ｎ比傾斜構造とは、突起の上の方と下の方のＯ／Ｎ比が異なり、突起の上の方が下の方に比べてＯ／Ｎ比が高い構造をいう。また、アミノ基は一般に塩素、次亜塩素酸等の酸化剤で容易に酸化されるため、アミノ基が多い場合には酸化による構造変化により塩素接触後の除去性が低下しやすい。突起の見かけ高さの７５～９８％の範囲の部分は、突起の見かけ高さの２～２５％の範囲の部分に比べて塩素が接近しやすいため、塩素による酸化劣化の影響を特に受けやすい。これらを勘案し、塩素が接近しやすい突起の見かけ高さ７５～９８％の範囲のＯ／Ｎ比を大きくし、ｙ／ｘ≧１．３を満たす突起を形成することで、複合半透膜の除去性能及び透水性を維持し、かつ、耐塩素性を向上できることを見出した。ｙ／ｘの値は、ｙ／ｘ≧１．６であることが好ましく、ｙ／ｘ≧２．０であることがより好ましい。
Since the O/N ratio in the main skeleton repeating unit of the crosslinked aromatic polyamide is the same both above and below the protrusion, the O/N ratio at the protrusion is substantially (crosslinked aromatic It is proportional to (the carboxy group present at the end of the polyamide)/(the amino group present at the end of the crosslinked aromatic polyamide). The terminal functional groups also affect the removal performance and water permeability of the composite semipermeable membrane. In a region where the density of amino groups is high, the separation functional layer has a sparse structure and has low resistance to water permeation, increasing water permeability, but the solute removal performance is insufficient. On the other hand, in a region where the amino group density is low, the separation functional layer has a dense structure and has a high water permeation resistance, so the water permeability is low, but the solute removal performance is improved. By providing an O/N ratio gradient structure within the protrusion and creating a small pore diameter portion and a highly charged portion, particularly high water permeability and removal performance can be achieved at the same time. Here, the O/N ratio gradient structure refers to a structure in which the O/N ratio is different between the upper part and the lower part of the protrusion, and the O/N ratio is higher on the upper part of the protrusion than on the lower part. . Furthermore, since amino groups are generally easily oxidized by oxidizing agents such as chlorine and hypochlorous acid, when there are many amino groups, the removability after contact with chlorine tends to decrease due to structural changes due to oxidation. The area between 75% and 98% of the apparent height of the protrusion is more susceptible to oxidative deterioration due to chlorine, as it is easier for chlorine to approach the area than the area between 2% and 25% of the apparent height of the protrusion. . Taking these into consideration, we created a composite semipermeable membrane by increasing the O/N ratio in the range of 75% to 98% of the apparent height of protrusions that are easily accessible to chlorine, and by forming protrusions that satisfy y/x≧1.3. It has been found that the removal performance and water permeability can be maintained, and the chlorine resistance can be improved. The value of y/x is preferably y/x≧1.6, more preferably y/x≧2.0.
本実施形態に係る複合半透膜において、突起は、原水が最も接近しやすい突起の見かけ高さの７５～９８％の範囲の部分に十分なカルボキシ基を含むことで、荷電が形成する静電場による塩除去性の向上及びカルボキシ基の親水性による透水性の向上が見込める観点から、ｙ≧０．９０を満たすことが好ましく、ｙ≧１．２を満たすことがより好ましい。一方で、架橋芳香族ポリアミドの分子間や分子内のカルボキシ基同士の強い水素結合による、架橋芳香族ポリアミドが構成する孔の閉塞を抑制する観点から、ｙ≦２．０であることが好ましい。すなわち、０．９０≦ｙ≦２．０が好ましい。
In the composite semipermeable membrane according to the present embodiment, the protrusions contain sufficient carboxyl groups in the range of 75 to 98% of the apparent height of the protrusions that are most easily accessible to raw water, so that the electrostatic field formed by charges It is preferable that y≧0.90 be satisfied, and it is more preferable that y≧1.2 be satisfied from the viewpoint of expected improvement in salt removability due to the hydrophilicity of the carboxy group and improvement in water permeability due to the hydrophilicity of the carboxy group. On the other hand, from the viewpoint of suppressing clogging of pores constituted by the crosslinked aromatic polyamide due to strong hydrogen bonds between the molecules of the crosslinked aromatic polyamide or between carboxyl groups within the molecule, it is preferable that y≦2.0. That is, 0.90≦y≦2.0 is preferable.
突起の見かけ高さの２～２５％の範囲におけるＯ／Ｎ比の平均値であるｘ、突起の見かけ高さ７５～９８％の範囲におけるＯ／Ｎ比の平均値であるｙは、後述する「（ｖ）突起のＯ／Ｎ比の測定」に記載の方法で算出することができる。このとき、突起の見かけ高さを求める際の微多孔性支持層表面の位置は、ＴＥＭ－ＥＥＬＳにより突起を測定した際に、微多孔性支持膜のみに含まれる元素が検出されなくなった位置とすることができる。
x, which is the average value of the O/N ratio in the range of 2 to 25% of the apparent height of the protrusion, and y, which is the average value of the O/N ratio in the range of 75 to 98% of the apparent height of the protrusion, will be described later. It can be calculated by the method described in "(v) Measurement of O/N ratio of protrusions". At this time, the position on the surface of the microporous support layer when calculating the apparent height of the protrusion is the position where elements contained only in the microporous support film are no longer detected when the protrusion is measured by TEM-EELS. can do.
本実施形態に係る複合半透膜において、突起は、アミノ基密度を適切とすることで透水性と除去性能を両立しやすい観点から、ｘ≧０．５０を満たすことが好ましい。また、突起の見かけ高さ７５～９８％部分に比べ寄与は小さいが、ｘ≧０．５０を満たすことで、酸化剤が突起の根本部分まで到達したときに起こる酸化劣化も抑制できる。一方で、架橋芳香族ポリアミドの分子間や分子内のカルボキシ基同士の強い水素結合による、架橋芳香族ポリアミドが構成する孔の閉塞を抑制する観点から、ｘ≦２．０であることが好ましい。すなわち、０．５０≦ｘ≦２．０が好ましい。
In the composite semipermeable membrane according to the present embodiment, the protrusions preferably satisfy x≧0.50 from the viewpoint of achieving both water permeability and removal performance by appropriate amino group density. Furthermore, although the contribution is small compared to the 75% to 98% portion of the apparent height of the protrusion, by satisfying x≧0.50, oxidative deterioration that occurs when the oxidizing agent reaches the root of the protrusion can also be suppressed. On the other hand, from the viewpoint of suppressing clogging of pores constituted by the crosslinked aromatic polyamide due to strong hydrogen bonds between the molecules of the crosslinked aromatic polyamide or between carboxyl groups within the molecule, it is preferable that x≦2.0. That is, 0.50≦x≦2.0 is preferable.
本実施形態に係る複合半透膜における突起の数密度は、十分な透水性を得る観点及び加圧時の突起の変形を抑制し安定した性能を得る観点から、突起の平均数密度が１３．０個／μｍ以上であることが好ましく、１５．０個／μｍ以上がより好ましい。また、突起の成長が十分に進行し、所望の透水性を備えた複合半透膜が得られやすい観点から、上述の突起の平均数密度は、５０．０個／μｍ以下が好ましく、４０．０個／μｍ以下がより好ましい。すなわち、突起の平均数密度は１３．０個／μｍ～５０．０個／μｍが好ましい。上述の突起の平均数密度は、微多孔性支持層の素材の変更、微多孔性支持層に用いる素材の濃度の変更、例えばＰＳｆ濃度の変更、界面重縮合の時間や温度により調整できる。
突起の平均数密度は、無作為に選択した複合半透膜の膜面方向に垂直な断面画像から抜き出した膜面方向の長さが２．０μｍである断面画像において、１０点平均面粗さの５分の１以上の高さを有する突起の数を計測することで算出できる。無作為に選択した１０枚の複合半透膜の膜面方向に垂直な断面画像について同様の測定を行い、得られた値の平均値を突起の平均数密度とする。 The average number density of the protrusions in the composite semipermeable membrane according to this embodiment is 13.0% from the viewpoint of obtaining sufficient water permeability and from the viewpoint of suppressing the deformation of the protrusions during pressurization and obtaining stable performance. It is preferably 0 pieces/μm or more, and more preferably 15.0 pieces/μm or more. Further, from the viewpoint that the growth of the protrusions sufficiently progresses and it is easy to obtain a composite semipermeable membrane having the desired water permeability, the above-mentioned average number density of the protrusions is preferably 50.0 pieces/μm or less, and 40.0 μm or less. More preferably, the number is 0 pieces/μm or less. That is, the average number density of protrusions is preferably 13.0 pieces/μm to 50.0 pieces/μm. The average number density of the protrusions described above can be adjusted by changing the material of the microporous support layer, changing the concentration of the material used for the microporous support layer, for example, changing the PSf concentration, and the time and temperature of interfacial polycondensation.
The average number density of protrusions is determined by the 10-point average surface roughness in a cross-sectional image whose length in the membrane surface direction is 2.0 μm extracted from a cross-sectional image perpendicular to the membrane surface direction of a composite semipermeable membrane selected at random. It can be calculated by measuring the number of protrusions having a height of one-fifth or more. Similar measurements are made on cross-sectional images perpendicular to the membrane surface direction of 10 randomly selected composite semipermeable membranes, and the average value of the obtained values is taken as the average number density of protrusions.
突起の平均数密度は、無作為に選択した複合半透膜の膜面方向に垂直な断面画像から抜き出した膜面方向の長さが２．０μｍである断面画像において、１０点平均面粗さの５分の１以上の高さを有する突起の数を計測することで算出できる。無作為に選択した１０枚の複合半透膜の膜面方向に垂直な断面画像について同様の測定を行い、得られた値の平均値を突起の平均数密度とする。 The average number density of the protrusions in the composite semipermeable membrane according to this embodiment is 13.0% from the viewpoint of obtaining sufficient water permeability and from the viewpoint of suppressing the deformation of the protrusions during pressurization and obtaining stable performance. It is preferably 0 pieces/μm or more, and more preferably 15.0 pieces/μm or more. Further, from the viewpoint that the growth of the protrusions sufficiently progresses and it is easy to obtain a composite semipermeable membrane having the desired water permeability, the above-mentioned average number density of the protrusions is preferably 50.0 pieces/μm or less, and 40.0 μm or less. More preferably, the number is 0 pieces/μm or less. That is, the average number density of protrusions is preferably 13.0 pieces/μm to 50.0 pieces/μm. The average number density of the protrusions described above can be adjusted by changing the material of the microporous support layer, changing the concentration of the material used for the microporous support layer, for example, changing the PSf concentration, and the time and temperature of interfacial polycondensation.
The average number density of protrusions is determined by the 10-point average surface roughness in a cross-sectional image whose length in the membrane surface direction is 2.0 μm extracted from a cross-sectional image perpendicular to the membrane surface direction of a composite semipermeable membrane selected at random. It can be calculated by measuring the number of protrusions having a height of one-fifth or more. Similar measurements are made on cross-sectional images perpendicular to the membrane surface direction of 10 randomly selected composite semipermeable membranes, and the average value of the obtained values is taken as the average number density of protrusions.
分離対象物質が複合半透膜内部に浸透することを防ぐため、分離機能層は、複合半透膜の表面側に配置されていることが好ましく、かつ、ろ過一次側に配置されていることがより好ましい。
In order to prevent the substance to be separated from permeating inside the composite semipermeable membrane, the separation functional layer is preferably placed on the surface side of the composite semipermeable membrane, and is preferably placed on the primary filtration side. More preferred.
２．複合半透膜の製造方法
本実施形態に係る複合半透膜の製造方法は、上述した所望の特徴を満たす複合半透膜が得られれば特に限定されないが、例えば、以下の方法で製造することができる。
例えば、微多孔性支持層と、上記微多孔性支持層上に設けられた分離機能層とを有する複合半透膜の製造方法は、
多官能芳香族アミン水溶液と、多官能芳香族酸ハロゲン化物の有機溶媒溶液とを用い、上記微多孔性支持層上で界面重縮合によって架橋芳香族ポリアミドを含有する層を形成する工程と、
架橋芳香族ポリアミドを含有する上記層にアミド基を含む化合物を含有する溶液を接触させる工程と、
を備える。 2. Method for manufacturing a composite semipermeable membrane The method for manufacturing a composite semipermeable membrane according to the present embodiment is not particularly limited as long as a composite semipermeable membrane satisfying the desired characteristics described above can be obtained, but for example, it can be manufactured by the following method. Can be done.
For example, a method for manufacturing a composite semipermeable membrane having a microporous support layer and a separation functional layer provided on the microporous support layer includes:
forming a layer containing a crosslinked aromatic polyamide on the microporous support layer by interfacial polycondensation using an aqueous polyfunctional aromatic amine solution and an organic solvent solution of a polyfunctional aromatic acid halide;
contacting the layer containing the crosslinked aromatic polyamide with a solution containing a compound containing an amide group;
Equipped with
本実施形態に係る複合半透膜の製造方法は、上述した所望の特徴を満たす複合半透膜が得られれば特に限定されないが、例えば、以下の方法で製造することができる。
例えば、微多孔性支持層と、上記微多孔性支持層上に設けられた分離機能層とを有する複合半透膜の製造方法は、
多官能芳香族アミン水溶液と、多官能芳香族酸ハロゲン化物の有機溶媒溶液とを用い、上記微多孔性支持層上で界面重縮合によって架橋芳香族ポリアミドを含有する層を形成する工程と、
架橋芳香族ポリアミドを含有する上記層にアミド基を含む化合物を含有する溶液を接触させる工程と、
を備える。 2. Method for manufacturing a composite semipermeable membrane The method for manufacturing a composite semipermeable membrane according to the present embodiment is not particularly limited as long as a composite semipermeable membrane satisfying the desired characteristics described above can be obtained, but for example, it can be manufactured by the following method. Can be done.
For example, a method for manufacturing a composite semipermeable membrane having a microporous support layer and a separation functional layer provided on the microporous support layer includes:
forming a layer containing a crosslinked aromatic polyamide on the microporous support layer by interfacial polycondensation using an aqueous polyfunctional aromatic amine solution and an organic solvent solution of a polyfunctional aromatic acid halide;
contacting the layer containing the crosslinked aromatic polyamide with a solution containing a compound containing an amide group;
Equipped with
（２－１）支持膜の製膜
支持膜の製膜方法としては、公知の方法が好適に利用できる。以下、微多孔性支持層の素材としてＰＳｆを用いる場合を例にとって述べる。 (2-1) Formation of support membrane As a method for forming the support membrane, known methods can be suitably used. An example in which PSf is used as the material for the microporous support layer will be described below.
支持膜の製膜方法としては、公知の方法が好適に利用できる。以下、微多孔性支持層の素材としてＰＳｆを用いる場合を例にとって述べる。 (2-1) Formation of support membrane As a method for forming the support membrane, known methods can be suitably used. An example in which PSf is used as the material for the microporous support layer will be described below.
まず、ＰＳｆを、ＰＳｆの良溶媒に溶解し、微多孔性支持層原液を調製する。ＰＳｆの良溶媒としては、例えば、Ｎ，Ｎ－ジメチルホルムアミド（以下、「ＤＭＦ」）が好ましい。
First, PSf is dissolved in a good solvent for PSf to prepare a microporous support layer stock solution. As a good solvent for PSf, for example, N,N-dimethylformamide (hereinafter referred to as "DMF") is preferable.
微多孔性支持層原液中のＰＳｆの濃度は、１２～２５質量％であることが好ましく、１４～２３質量％であることがより好ましい。高分子溶液におけるポリマー濃度（すなわち固形分濃度）が高いほど、微多孔性支持層の表面における粒の数密度が大きい微多孔性支持層が得られ、その結果、分離機能層の突起の数密度も高くなり、透水性が向上する。また、分離機能層形成時のモノマー供給速度が小さくなりすぎない程度にポリマー濃度が低いことで、微多孔性支持層の表面細孔径が調整され、分離機能層形成時に、適切な高さ及び／又は見かけ高さを持つ突起が形成される。微多孔性支持層原液中のＰＳｆの濃度をこの範囲内とすることで、得られる微多孔性支持層の強度と透過性能とを両立することができる。なお、微多孔性支持層原液中の素材の濃度の好ましい範囲は、用いる素材、良溶媒等によって適宜調整することができる。
The concentration of PSf in the microporous support layer stock solution is preferably 12 to 25% by mass, more preferably 14 to 23% by mass. The higher the polymer concentration (i.e., solid content concentration) in the polymer solution, the higher the number density of particles on the surface of the microporous support layer, which results in a microporous support layer with a higher number density of protrusions on the separation functional layer. The water permeability also increases. In addition, by keeping the polymer concentration low to the extent that the monomer supply rate during the formation of the separation functional layer is not too low, the surface pore diameter of the microporous support layer can be adjusted, and the appropriate height and/or height can be adjusted during the formation of the separation functional layer. Or a protrusion with an apparent height is formed. By setting the concentration of PSf in the stock solution of the microporous support layer within this range, it is possible to achieve both strength and permeability of the resulting microporous support layer. Note that the preferable range of the concentration of the material in the stock solution of the microporous support layer can be adjusted as appropriate depending on the material used, the good solvent, and the like.
次に、得られた微多孔性支持層原液を、基材表面に塗布し、ＰＳｆの非溶媒を含む凝固浴に浸漬する。
凝固浴に含まれるＰＳｆの非溶媒としては、例えば、水が好ましい。基材表面に塗布した微多孔性支持層原液を、ＰＳｆの非溶媒を含む凝固浴に接触させることで、非溶媒誘起相分離によって微多孔性支持層原液が凝固し、基材表面に微多孔性支持層が形成した支持膜を得ることができる。
凝固浴は、ＰＳｆの非溶媒のみで構成されていてもよく、微多孔性支持層原液を凝固可能な範囲で、ＰＳｆの良溶媒を含んでいてもよい。
得られた支持膜を、分離機能層の形成の前に洗浄することで、膜中に残存する溶媒を除去してもよい。 Next, the obtained microporous support layer stock solution is applied to the surface of the substrate and immersed in a coagulation bath containing a non-solvent of PSf.
As the non-solvent for PSf contained in the coagulation bath, for example, water is preferable. By bringing the microporous support layer stock solution applied onto the substrate surface into contact with a coagulation bath containing a PSf non-solvent, the microporous support layer stock solution is coagulated by non-solvent induced phase separation, creating microporous pores on the substrate surface. A support membrane having a sexual support layer formed thereon can be obtained.
The coagulation bath may be composed only of a non-solvent for PSf, or may contain a good solvent for PSf to the extent that the stock solution of the microporous support layer can be coagulated.
The solvent remaining in the membrane may be removed by washing the obtained support membrane before forming the separation functional layer.
凝固浴に含まれるＰＳｆの非溶媒としては、例えば、水が好ましい。基材表面に塗布した微多孔性支持層原液を、ＰＳｆの非溶媒を含む凝固浴に接触させることで、非溶媒誘起相分離によって微多孔性支持層原液が凝固し、基材表面に微多孔性支持層が形成した支持膜を得ることができる。
凝固浴は、ＰＳｆの非溶媒のみで構成されていてもよく、微多孔性支持層原液を凝固可能な範囲で、ＰＳｆの良溶媒を含んでいてもよい。
得られた支持膜を、分離機能層の形成の前に洗浄することで、膜中に残存する溶媒を除去してもよい。 Next, the obtained microporous support layer stock solution is applied to the surface of the substrate and immersed in a coagulation bath containing a non-solvent of PSf.
As the non-solvent for PSf contained in the coagulation bath, for example, water is preferable. By bringing the microporous support layer stock solution applied onto the substrate surface into contact with a coagulation bath containing a PSf non-solvent, the microporous support layer stock solution is coagulated by non-solvent induced phase separation, creating microporous pores on the substrate surface. A support membrane having a sexual support layer formed thereon can be obtained.
The coagulation bath may be composed only of a non-solvent for PSf, or may contain a good solvent for PSf to the extent that the stock solution of the microporous support layer can be coagulated.
The solvent remaining in the membrane may be removed by washing the obtained support membrane before forming the separation functional layer.
（２－２）分離機能層の重合工程
(2-2) Polymerization process of separation functional layer
架橋芳香族ポリアミドを含有する分離機能層の形成方法について、「（２－１）支持膜の製膜」で得られた支持膜上で、多官能芳香族アミンと多官能芳香族酸クロリドとを重合して固化させる方法を例にとって述べる。重合方法としては、生産性、性能の観点から界面重縮合法が最も好ましい。以下、界面重縮合の工程について説明する。
Regarding the method for forming a separation functional layer containing a crosslinked aromatic polyamide, a polyfunctional aromatic amine and a polyfunctional aromatic acid chloride are mixed on the support film obtained in "(2-1) Formation of support film". The method of polymerization and solidification will be described as an example. As the polymerization method, interfacial polycondensation method is most preferred from the viewpoint of productivity and performance. The interfacial polycondensation process will be explained below.
界面重縮合の工程は、（ａ）多官能芳香族アミンを含有する水溶液を支持膜に接触させる工程と、（ｂ）多官能芳香族酸クロリドを含有する有機溶媒溶液を、多官能芳香族アミンを含有する水溶液を接触させた支持膜に接触させ加熱する工程と、（ｃ）接触後の有機溶媒溶液を液切りする工程と、（ｄ）界面重縮合により生成した分離機能層を、アミド基を含む化合物を含有する溶液Ａに接触する工程と、（ｅ）複合半透膜を熱水で洗浄する工程、とを備えることが好ましい。
The step of interfacial polycondensation includes (a) a step of bringing an aqueous solution containing a polyfunctional aromatic amine into contact with a support membrane, and (b) a step of bringing an organic solvent solution containing a polyfunctional aromatic acid chloride into contact with a polyfunctional aromatic amine. (c) draining the organic solvent solution after contact; and (d) separating the separation functional layer produced by interfacial polycondensation from the amide group. It is preferable to include the steps of: (e) cleaning the composite semipermeable membrane with hot water; and (e) cleaning the composite semipermeable membrane with hot water.
微多孔性支持層、多官能芳香族アミン及び多官能芳香族酸ハロゲン化物としては、上述のものを挙げることができ、好ましいものも同様である。
As the microporous support layer, the polyfunctional aromatic amine, and the polyfunctional aromatic acid halide, those mentioned above can be mentioned, and preferred ones are also the same.
工程（ａ）において、多官能芳香族アミン水溶液における多官能芳香族アミンの濃度は０．１～２０質量％の範囲であることが好ましく、０．５～１５質量％の範囲内であることがより好ましい。多官能芳香族アミンの濃度がこの範囲であると、製造後の複合半透膜は十分な溶質除去性能及び透水性を得ることができる。なお、多官能芳香族アミンは、２種類以上を用いてもよい。
In step (a), the concentration of the polyfunctional aromatic amine in the aqueous polyfunctional aromatic amine solution is preferably in the range of 0.1 to 20% by mass, and preferably in the range of 0.5 to 15% by mass. More preferred. When the concentration of the polyfunctional aromatic amine is within this range, the manufactured composite semipermeable membrane can have sufficient solute removal performance and water permeability. Note that two or more types of polyfunctional aromatic amines may be used.
多官能芳香族アミン水溶液には、多官能芳香族アミンと多官能芳香族酸ハロゲン化物との反応を妨害しないものであれば、界面活性剤、有機溶媒、アルカリ性化合物又は酸化防止剤等が含まれていてもよい。界面活性剤は、支持膜表面の濡れ性を向上させ、多官能芳香族アミン水溶液と非極性溶媒との間の界面張力を減少させる効果がある。有機溶媒は界面重縮合反応の触媒として働くことがあり、添加することにより界面重縮合反応を効率よく行える場合がある。
The polyfunctional aromatic amine aqueous solution does not contain surfactants, organic solvents, alkaline compounds, antioxidants, etc. as long as they do not interfere with the reaction between the polyfunctional aromatic amine and the polyfunctional aromatic acid halide. You can leave it there. The surfactant has the effect of improving the wettability of the support membrane surface and reducing the interfacial tension between the polyfunctional aromatic amine aqueous solution and the nonpolar solvent. The organic solvent may act as a catalyst for the interfacial polycondensation reaction, and by adding the organic solvent, the interfacial polycondensation reaction may be carried out efficiently.
工程（ａ）において、多官能芳香族アミン水溶液は、支持膜に均一、かつ、連続的に接触させることが好ましい。具体的には、例えば、支持膜上に多官能芳香族アミン水溶液をコーティングする方法又は支持膜を多官能芳香族アミン水溶液に浸漬する方法が挙げられる。支持膜と多官能芳香族アミン水溶液との接触時間は、１秒～１０分であることが好ましく、３秒～３分であることがより好ましい。
In step (a), the polyfunctional aromatic amine aqueous solution is preferably brought into contact with the support membrane uniformly and continuously. Specifically, for example, a method of coating a polyfunctional aromatic amine aqueous solution on the support membrane or a method of immersing the support membrane in a polyfunctional aromatic amine aqueous solution can be mentioned. The contact time between the support membrane and the polyfunctional aromatic amine aqueous solution is preferably 1 second to 10 minutes, more preferably 3 seconds to 3 minutes.
多官能芳香族アミン水溶液を支持膜に接触させた後は、支持膜上に液滴が残らないよう十分に液切りすることが好ましい。十分に液切りすることで、複合半透膜形成後に液滴残存部分が膜欠点となって分離性能が低下することを防ぐことができる。液切りの方法としては、例えば、日本国特開平２－７８４２８号公報に記載されているように、多官能芳香族アミン水溶液接触後の支持膜を垂直方向に把持して過剰の該水溶液を自然流下させる方法又はエアーノズルから窒素等の気流を吹き付け、強制的に液切りする方法が挙げられる。また、液切り後、膜面を乾燥させて多官能芳香族アミン水溶液の水分を一部除去することもできる。
After bringing the polyfunctional aromatic amine aqueous solution into contact with the support membrane, it is preferable to drain the liquid sufficiently so that no droplets remain on the support membrane. By sufficiently draining the liquid, it is possible to prevent the remaining portion of the droplet from becoming a membrane defect after forming the composite semipermeable membrane, thereby preventing the separation performance from deteriorating. As a method of draining the liquid, for example, as described in Japanese Patent Application Laid-Open No. 2-78428, the support membrane after contact with the polyfunctional aromatic amine aqueous solution is held vertically and the excess aqueous solution is naturally drained. Examples include a method of letting the liquid flow down, or a method of forcibly draining the liquid by blowing an air stream of nitrogen or the like from an air nozzle. Further, after draining, the membrane surface can be dried to partially remove water from the polyfunctional aromatic amine aqueous solution.
工程（ｂ）において、多官能芳香族酸クロリドとしては、例えば、ＴＭＣ、ビフェニルジカルボン酸ジクロリド、アゾベンゼンジカルボン酸ジクロリド、テレフタル酸クロリド、イソフタル酸クロリド、ナフタレンジカルボン酸クロリド、２，５－フランジカルボン酸クロリド等が挙げられる。これらの多官能芳香族酸クロリドは、単独で用いてもよいし、２種以上を併用してもよい。
In step (b), the polyfunctional aromatic acid chloride includes, for example, TMC, biphenyldicarboxylic acid dichloride, azobenzenedicarboxylic acid dichloride, terephthalic acid chloride, isophthalic acid chloride, naphthalenedicarboxylic acid chloride, 2,5-furandicarboxylic acid chloride. etc. These polyfunctional aromatic acid chlorides may be used alone or in combination of two or more.
有機溶媒は、水と非混和性であり、多官能芳香族酸クロリドを溶解し、支持膜を侵さず、かつ、多官能芳香族アミン及び多官能芳香族酸クロリドに対して不活性であることが好ましい。有機溶媒としては、例えば、ｎ－ノナン、ｎ－デカン、ｎ－ウンデカン、ｎ－ドデカン、イソオクタン、イソデカン、イソドデカン等の炭化水素化合物又はこれらの混合溶媒が挙げられる。
The organic solvent must be immiscible with water, dissolve the polyfunctional aromatic acid chloride, do not attack the support membrane, and be inert to the polyfunctional aromatic amine and the polyfunctional aromatic acid chloride. is preferred. Examples of the organic solvent include hydrocarbon compounds such as n-nonane, n-decane, n-undecane, n-dodecane, isooctane, isodecane, and isododecane, and mixed solvents thereof.
有機溶媒溶液中の多官能芳香族酸クロリドの濃度は、０．０１～１０質量％であることが好ましく、０．０２～４質量％であることがより好ましく、０．０３～２質量％であることがさらに好ましい。多官能芳香族酸クロリドの濃度が０．０１質量％以上であることで、十分な反応速度で重合を進行させることができる。一方、多官能芳香族酸クロリドの濃度が１０質量％以下であることで、重合中の副反応の発生を抑制することができる。また、有機溶媒溶液には、重合を阻害しない範囲であれば、必要に応じて、界面活性剤等の化合物が含まれていてもよい。
The concentration of polyfunctional aromatic acid chloride in the organic solvent solution is preferably 0.01 to 10% by mass, more preferably 0.02 to 4% by mass, and more preferably 0.03 to 2% by mass. It is even more preferable that there be. When the concentration of the polyfunctional aromatic acid chloride is 0.01% by mass or more, polymerization can proceed at a sufficient reaction rate. On the other hand, when the concentration of the polyfunctional aromatic acid chloride is 10% by mass or less, the occurrence of side reactions during polymerization can be suppressed. Further, the organic solvent solution may contain a compound such as a surfactant, if necessary, as long as it does not inhibit polymerization.
多官能芳香族酸クロリドの有機溶媒溶液の、多官能芳香族アミン水溶液と接触させた支持膜への接触の方法は、工程（ａ）における多官能芳香族アミン水溶液の支持膜への接触方法と同様に行えばよい。多官能芳香族アミン水溶液と接触させた支持膜と多官能芳香族酸クロリド溶液を接触させることで、分離機能層が形成され始める。
多官能芳香族アミンを含有する水溶液を接触させた微多孔性支持層と多官能芳香族酸ハロゲン化物を溶解させた溶液を接触させる温度は２５～６０℃であることが好ましく、３０℃～５５℃がより好ましい。２５℃以上とすることで、突起の高さ及び／又は見かけ高さが十分なものとなる。また、６０℃以下とすることで、反応速度が適度になり、薄膜厚みの増大や突起の合一化の進行が抑制され、製造後の複合半透膜において十分な透水性が得られやすい。また、最初に支持膜から界面重縮合場に供給されるアミン量が適切となり、突起の見かけ高さの２～２５％の範囲におけるアミノ基量が抑えられ、ｘ≧０．５０を満たしやすくなる。さらに、接触させる温度が２５～６０℃であることで、突起の数が増え、実質的に反応界面の表面積が増えるため、ポリアミド量が大きくなるとともに突起の平均厚みＴ２５及びＴ９８の肥大化が抑制できる。温度付与方法は、支持膜を加温してもよく、加温した多官能芳香族酸ハロゲン化物の有機溶媒溶液を接触させてもよい。多官能芳香族アミン水溶液と多官能芳香族酸ハロゲン化物溶液とを接触させた直後の膜面の温度は、放射温度計のような非接触型温度計により測定することができる。 The method of contacting the organic solvent solution of polyfunctional aromatic acid chloride with the support membrane that has been brought into contact with the polyfunctional aromatic amine aqueous solution is the same as the method of contacting the polyfunctional aromatic amine aqueous solution with the support membrane in step (a). You can do the same. A separation functional layer begins to be formed by bringing the polyfunctional aromatic acid chloride solution into contact with the support membrane that has been brought into contact with the polyfunctional aromatic amine aqueous solution.
The temperature at which the microporous support layer brought into contact with the aqueous solution containing the polyfunctional aromatic amine and the solution in which the polyfunctional aromatic acid halide is dissolved is preferably 25 to 60°C, and preferably 30 to 55°C. ℃ is more preferable. By setting the temperature to 25° C. or higher, the height and/or apparent height of the protrusion becomes sufficient. Further, by setting the temperature to 60° C. or lower, the reaction rate becomes appropriate, the increase in the thickness of the thin film and the progress of coalescence of protrusions are suppressed, and sufficient water permeability is easily obtained in the manufactured composite semipermeable membrane. In addition, the amount of amine initially supplied from the support film to the interfacial polycondensation site becomes appropriate, suppressing the amount of amino groups in the range of 2 to 25% of the apparent height of the protrusions, and making it easier to satisfy x≧0.50. . Furthermore, since the contact temperature is 25 to 60°C, the number of protrusions increases and the surface area of the reaction interface increases, which increases the amount of polyamide and suppresses the increase in the average thicknesses T25 and T98 of the protrusions. can. As for the temperature application method, the support film may be heated, or a heated solution of a polyfunctional aromatic acid halide in an organic solvent may be brought into contact with the support film. The temperature of the membrane surface immediately after the polyfunctional aromatic amine aqueous solution and the polyfunctional aromatic acid halide solution are brought into contact can be measured with a non-contact thermometer such as a radiation thermometer.
多官能芳香族アミンを含有する水溶液を接触させた微多孔性支持層と多官能芳香族酸ハロゲン化物を溶解させた溶液を接触させる温度は２５～６０℃であることが好ましく、３０℃～５５℃がより好ましい。２５℃以上とすることで、突起の高さ及び／又は見かけ高さが十分なものとなる。また、６０℃以下とすることで、反応速度が適度になり、薄膜厚みの増大や突起の合一化の進行が抑制され、製造後の複合半透膜において十分な透水性が得られやすい。また、最初に支持膜から界面重縮合場に供給されるアミン量が適切となり、突起の見かけ高さの２～２５％の範囲におけるアミノ基量が抑えられ、ｘ≧０．５０を満たしやすくなる。さらに、接触させる温度が２５～６０℃であることで、突起の数が増え、実質的に反応界面の表面積が増えるため、ポリアミド量が大きくなるとともに突起の平均厚みＴ２５及びＴ９８の肥大化が抑制できる。温度付与方法は、支持膜を加温してもよく、加温した多官能芳香族酸ハロゲン化物の有機溶媒溶液を接触させてもよい。多官能芳香族アミン水溶液と多官能芳香族酸ハロゲン化物溶液とを接触させた直後の膜面の温度は、放射温度計のような非接触型温度計により測定することができる。 The method of contacting the organic solvent solution of polyfunctional aromatic acid chloride with the support membrane that has been brought into contact with the polyfunctional aromatic amine aqueous solution is the same as the method of contacting the polyfunctional aromatic amine aqueous solution with the support membrane in step (a). You can do the same. A separation functional layer begins to be formed by bringing the polyfunctional aromatic acid chloride solution into contact with the support membrane that has been brought into contact with the polyfunctional aromatic amine aqueous solution.
The temperature at which the microporous support layer brought into contact with the aqueous solution containing the polyfunctional aromatic amine and the solution in which the polyfunctional aromatic acid halide is dissolved is preferably 25 to 60°C, and preferably 30 to 55°C. ℃ is more preferable. By setting the temperature to 25° C. or higher, the height and/or apparent height of the protrusion becomes sufficient. Further, by setting the temperature to 60° C. or lower, the reaction rate becomes appropriate, the increase in the thickness of the thin film and the progress of coalescence of protrusions are suppressed, and sufficient water permeability is easily obtained in the manufactured composite semipermeable membrane. In addition, the amount of amine initially supplied from the support film to the interfacial polycondensation site becomes appropriate, suppressing the amount of amino groups in the range of 2 to 25% of the apparent height of the protrusions, and making it easier to satisfy x≧0.50. . Furthermore, since the contact temperature is 25 to 60°C, the number of protrusions increases and the surface area of the reaction interface increases, which increases the amount of polyamide and suppresses the increase in the average thicknesses T25 and T98 of the protrusions. can. As for the temperature application method, the support film may be heated, or a heated solution of a polyfunctional aromatic acid halide in an organic solvent may be brought into contact with the support film. The temperature of the membrane surface immediately after the polyfunctional aromatic amine aqueous solution and the polyfunctional aromatic acid halide solution are brought into contact can be measured with a non-contact thermometer such as a radiation thermometer.
多官能芳香族酸クロリドの有機溶媒溶液を接触させ分離機能層を形成した後、分離機能層及び支持膜を加熱処理してもよい。加熱処理する場合、加熱温度は５０～１８０℃が好ましく、６０～１６０℃がより好ましく、８０～１５０℃がさらに好ましい。加熱温度を上記範囲内とすることで、突起の合一化が抑制され、突起の数密度が適切になるとともに突起の平均厚みの厚膜化も抑制され、良好な透水性が得られやすい。
After forming a separation functional layer by contacting with an organic solvent solution of a polyfunctional aromatic acid chloride, the separation functional layer and the support membrane may be heat-treated. In the case of heat treatment, the heating temperature is preferably 50 to 180°C, more preferably 60 to 160°C, even more preferably 80 to 150°C. By setting the heating temperature within the above range, coalescence of the protrusions is suppressed, the number density of the protrusions becomes appropriate, and an increase in the average thickness of the protrusions is also suppressed, making it easy to obtain good water permeability.
工程（ｃ）において、支持膜及び分離機能層から、反応後の有機溶媒溶液を液切りする工程により、有機溶媒を除去する。有機溶媒の除去は、例えば、膜を垂直方向に把持して過剰の有機溶媒を自然流下して除去する方法、送風機で風を吹き付けることで有機溶媒を乾燥除去する方法、水とエアーの混合流体で過剰の有機溶媒を除去する方法等を用いることができる。
In step (c), the organic solvent is removed from the support membrane and the separation functional layer by draining the organic solvent solution after the reaction. The organic solvent can be removed, for example, by holding the membrane vertically and removing the excess organic solvent by gravity, by blowing air with a blower to dry and remove the organic solvent, or by using a mixed fluid of water and air. A method of removing excess organic solvent can be used.
工程（ｄ）において、界面重縮合により生成した機能層を、アミド基を含む化合物を含有する溶液Ａに接触させる。アミド基を含む化合物としては、例えば、鎖状アミド化合物、環状アミド化合物等が挙げられる。鎖状アミド化合物として、例えば、Ｎ－メチルホルムアミド、Ｎ，Ｎ－ジメチルホルムアミド、Ｎ，Ｎ－ジメチルアセトアミド、Ｎ，Ｎ－ジエチルホルムアミド、Ｎ，Ｎ－ジイソプロピルホルムアミド、Ｎ，Ｎ－ジブチルホルムアミド、Ｎ，Ｎ－ジエチルアセトアミド、テトラメチル尿素、テトラエチル尿素、Ｎ，Ｎ－ジエチルドデカンアミド等が挙げられる。環状アミド化合物として、例えば、Ｎ－メチルピロリジノン、γ－ブチロラクタム、ε－カプロラクタム、１，３－ジメチル－２－イミダゾリジノン、Ｎ，Ｎ’－ジメチルプロピレン尿素等が挙げられる。
In step (d), the functional layer produced by interfacial polycondensation is brought into contact with solution A containing a compound containing an amide group. Examples of the compound containing an amide group include a chain amide compound, a cyclic amide compound, and the like. Examples of chain amide compounds include N-methylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, N,N-diisopropylformamide, N,N-dibutylformamide, N, Examples include N-diethylacetamide, tetramethylurea, tetraethylurea, N,N-diethyldodecanamide and the like. Examples of the cyclic amide compound include N-methylpyrrolidinone, γ-butyrolactam, ε-caprolactam, 1,3-dimethyl-2-imidazolidinone, N,N'-dimethylpropylene urea, and the like.
工程（ｃ）直後の分離機能層には、多官能芳香族酸クロリド末端、酸クロリド末端が加水分解したカルボキシ末端、多官能芳香族アミノ基末端を有するポリアミド、オリゴマー、及び未反応モノマーが存在している。アミド基を含む化合物を含有する溶液Ａと接触させることで、溶液Ａのアミド基と分離機能層中に存在するアミノ基が水素結合により相互作用し、アミノ基を有するオリゴマーや未反応モノマーが分離機能層から除去されやすくなるため、分離機能層に含まれる窒素原子（Ｎ）が減少する。また、アミド基を有する化合物が酸クロリド末端に作用し、加水分解を促進するため、分離機能層に含まれるカルボキシ基の量が増加し、酸素原子（Ｏ）も増加する。分離機能層における突起の見かけ高さ７５～９８％の範囲の部分は、２～２５％の範囲の部分に比べて立体障害が小さいため、アミド基を有する化合物が接近しやすく、上記の作用による効果が大きい。したがって、分離機能層における突起は、突起の見かけ高さ７５～９８％の範囲のＯ／Ｎ比の平均値であるｙが大きくなり、ｙ≧０．９０、ｙ／ｘ≧１．３を満たしやすくなる。また、酸クロリド末端の加水分解が促進され、アミノ基を有するオリゴマー、未反応モノマーが除去されることにより、突起の高さ７５～９８％の範囲の重合反応は、突起の高さ２～２５％の範囲の重合反応に比べ早く停止反応が進むため、Ｔ９８／Ｔ２５が０．９５以下を満たしやすくなる。
Immediately after step (c), the separation functional layer contains a polyamide having a polyfunctional aromatic acid chloride end, a carboxy end obtained by hydrolyzing the acid chloride end, a polyamide having a polyfunctional aromatic amino group end, an oligomer, and an unreacted monomer. ing. By contacting solution A containing a compound containing an amide group, the amide group of solution A and the amino group present in the separation functional layer interact through hydrogen bonding, and oligomers and unreacted monomers having amino groups are separated. Since nitrogen atoms (N) are easily removed from the functional layer, the number of nitrogen atoms (N) contained in the separation functional layer decreases. Further, since the compound having an amide group acts on the acid chloride terminal and promotes hydrolysis, the amount of carboxy groups contained in the separation functional layer increases, and the number of oxygen atoms (O) also increases. The portions in the separation functional layer where the apparent height of the protrusions ranges from 75% to 98% have less steric hindrance than the portions where the apparent height ranges from 2% to 25%, so compounds having an amide group can easily approach them, resulting in the above effects. Great effect. Therefore, for the protrusions in the separation functional layer, y, which is the average value of the O/N ratio in the range of 75% to 98% of the apparent height of the protrusions, becomes large and satisfies y≧0.90 and y/x≧1.3. It becomes easier. In addition, the hydrolysis of the acid chloride terminal is promoted and the amino group-containing oligomer and unreacted monomer are removed, so that the polymerization reaction in the protrusion height range of 75 to 98% can be carried out at a protrusion height of 2 to 25%. Since the termination reaction proceeds faster than the polymerization reaction in the % range, it becomes easier to satisfy T98/T25 of 0.95 or less.
溶液Ａにおけるアミド基を含む化合物の濃度は、０．１～４０質量％であることが好ましく、１．０～３０質量％がより好ましい。濃度が０．１質量％以上であることで、上記の効果が十分に得られる。また、濃度が４０質量％以下であることで、アミド基を含む化合物が支持膜を形成するＰＳｆの良溶媒であったとしても、分離機能層や支持膜を侵襲しにくく除去率の低下を抑制できる。分離機能層を溶液Ａと接触させる時間は５分以内が好ましく、２分以内がより好ましい。接触させる時間を５分以内とすることで、突起の見かけ高さ２～２５％の範囲の部分への作用が抑制され、ｙ／ｘ≧１．３を満たしやすくなる。接触させる溶液Ａの温度は、０～５０℃が好ましく、５～４０℃がより好ましい。５０℃以下の温度で接触させることで、ポリアミド鎖の運動性の上昇が抑制され、突起の見かけ高さ２～２５％の範囲の部分への作用も抑制され、ｙ／ｘ≧１．３を満たしやすくなる。接触させる方法としては、溶液Ａを複合半透膜表面にコーティングする方法や、複合半透膜を溶液Ａに浸漬する方法が挙げられる。
The concentration of the compound containing an amide group in solution A is preferably 0.1 to 40% by mass, more preferably 1.0 to 30% by mass. When the concentration is 0.1% by mass or more, the above effects can be sufficiently obtained. In addition, since the concentration is 40% by mass or less, even if the compound containing an amide group is a good solvent for PSf that forms the support membrane, it will not attack the separation functional layer or the support membrane and suppress a decrease in removal rate. can. The time for which the separation functional layer is brought into contact with solution A is preferably within 5 minutes, more preferably within 2 minutes. By keeping the contact time within 5 minutes, the effect on the portion of the protrusion with an apparent height of 2 to 25% is suppressed, making it easier to satisfy y/x≧1.3. The temperature of solution A to be brought into contact is preferably 0 to 50°C, more preferably 5 to 40°C. By contacting at a temperature of 50°C or lower, the increase in the mobility of the polyamide chains is suppressed, and the effect on the portions with an apparent height of 2 to 25% of the protrusions is also suppressed, and y/x≧1.3 is suppressed. Easier to fill. Examples of the contacting method include a method of coating the surface of the composite semipermeable membrane with solution A, and a method of immersing the composite semipermeable membrane in solution A.
工程（ｅ）において、複合半透膜を熱水で洗浄する。熱水の温度は４０～９５℃が好ましく、６０～９５℃がより好ましい。熱水の温度が４０℃以上であることで、膜中に残存する未反応物やオリゴマーを十分に除去することができる。一方、熱水の温度が９５℃以下であることで、複合半透膜の収縮度が大きくならず、良好な透過性能を維持することができる。なお、熱水の温度の好ましい範囲は、用いる多官能芳香族アミンや多官能芳香族酸クロリドによって適宜調整することができる。
In step (e), the composite semipermeable membrane is washed with hot water. The temperature of the hot water is preferably 40 to 95°C, more preferably 60 to 95°C. When the temperature of the hot water is 40° C. or higher, unreacted substances and oligomers remaining in the membrane can be sufficiently removed. On the other hand, when the temperature of the hot water is 95° C. or lower, the degree of shrinkage of the composite semipermeable membrane does not become large, and good permeation performance can be maintained. Note that the preferable temperature range of the hot water can be adjusted as appropriate depending on the polyfunctional aromatic amine or polyfunctional aromatic acid chloride used.
また、架橋芳香族ポリアミド中に存在するアミノ基を適宜選択した化学反応による改質処理により、新たな官能基を導入することで、複合半透膜の性能を向上することができる。
新たな官能基としては、例えば、アルキル基、アルケニル基、アルキニル基、ハロゲノ基、水酸基、エーテル基、チオエーテル基、エステル基、アルデヒド基、ニトロ基、ニトロソ基、ニトリル基、アゾ基等が挙げられる。 Furthermore, the performance of the composite semipermeable membrane can be improved by introducing a new functional group through a modification treatment using an appropriately selected chemical reaction on the amino groups present in the crosslinked aromatic polyamide.
Examples of new functional groups include alkyl groups, alkenyl groups, alkynyl groups, halogeno groups, hydroxyl groups, ether groups, thioether groups, ester groups, aldehyde groups, nitro groups, nitroso groups, nitrile groups, and azo groups. .
新たな官能基としては、例えば、アルキル基、アルケニル基、アルキニル基、ハロゲノ基、水酸基、エーテル基、チオエーテル基、エステル基、アルデヒド基、ニトロ基、ニトロソ基、ニトリル基、アゾ基等が挙げられる。 Furthermore, the performance of the composite semipermeable membrane can be improved by introducing a new functional group through a modification treatment using an appropriately selected chemical reaction on the amino groups present in the crosslinked aromatic polyamide.
Examples of new functional groups include alkyl groups, alkenyl groups, alkynyl groups, halogeno groups, hydroxyl groups, ether groups, thioether groups, ester groups, aldehyde groups, nitro groups, nitroso groups, nitrile groups, and azo groups. .
３．複合半透膜の利用
複合半透膜は、プラスチックネットなどの供給水流路材と、トリコットなどの透過水流路材と、必要に応じて耐圧性を高めるためのフィルムと共に、多数の孔を穿設した筒状の集水管の周りに巻回され、スパイラル型の複合半透膜エレメントとして好適に用いられる。さらに、このエレメントを直列又は並列に接続して圧力容器に収納した複合半透膜モジュールとすることもできる。 3. Utilization of composite semi-permeable membranes Composite semi-permeable membranes are made of feed water channel material such as plastic net, permeate water channel material such as tricot, and if necessary, a film to increase pressure resistance, as well as a large number of holes. The membrane element is wound around a cylindrical water collecting pipe, and is suitably used as a spiral-type composite semipermeable membrane element. Furthermore, a composite semipermeable membrane module can be obtained in which these elements are connected in series or in parallel and housed in a pressure vessel.
複合半透膜は、プラスチックネットなどの供給水流路材と、トリコットなどの透過水流路材と、必要に応じて耐圧性を高めるためのフィルムと共に、多数の孔を穿設した筒状の集水管の周りに巻回され、スパイラル型の複合半透膜エレメントとして好適に用いられる。さらに、このエレメントを直列又は並列に接続して圧力容器に収納した複合半透膜モジュールとすることもできる。 3. Utilization of composite semi-permeable membranes Composite semi-permeable membranes are made of feed water channel material such as plastic net, permeate water channel material such as tricot, and if necessary, a film to increase pressure resistance, as well as a large number of holes. The membrane element is wound around a cylindrical water collecting pipe, and is suitably used as a spiral-type composite semipermeable membrane element. Furthermore, a composite semipermeable membrane module can be obtained in which these elements are connected in series or in parallel and housed in a pressure vessel.
また、上記の複合半透膜やそのエレメント、モジュールは、それらに供給水を供給するポンプや、その供給水を前処理する装置などと組み合わせて、流体分離装置を構成することができる。この分離装置を用いることにより、供給水を飲料水などの透過水と膜を透過しなかった濃縮水とに分離して、目的にあった水を得ることができる。
Furthermore, the above-described composite semipermeable membrane, its elements, and modules can be combined with a pump that supplies water to them, a device that pre-treats the water, and the like to configure a fluid separation device. By using this separation device, it is possible to separate feed water into permeated water such as drinking water and concentrated water that has not passed through the membrane, thereby obtaining water suitable for the purpose.
上記複合半透膜によって処理される供給水としては、海水、かん水、排水などの５００ｍｇ／Ｌ以上１００ｇ／Ｌ以下の総溶解固形分（Ｔｏｔａｌ Ｄｉｓｓｏｌｖｅｄ Ｓｏｌｉｄｓ：以下、「ＴＤＳ」）を含有する液状混合物が挙げられる。一般に、ＴＤＳは総溶解固形分量を指し、「質量÷体積（質量を体積で除した値）」あるいは「質量比」で表される。定義によれば、０．４５μｍのフィルターで濾過した溶液を３９．５℃以上４０．５℃以下の温度で蒸発させ残留物の重さから算出できるが、より簡便には実用塩分（Ｓ）から換算される。
The feed water to be treated by the composite semipermeable membrane is a liquid mixture containing total dissolved solids (hereinafter referred to as "TDS") of 500 mg/L or more and 100 g/L or less, such as seawater, brine, and waste water. can be mentioned. Generally, TDS refers to the total amount of dissolved solids, and is expressed as "mass divided by volume (mass divided by volume)" or "mass ratio." According to the definition, it can be calculated from the weight of the residue obtained by evaporating a solution filtered through a 0.45 μm filter at a temperature between 39.5°C and 40.5°C, but more simply, it can be calculated from the practical salinity (S). converted.
流体分離装置の操作圧力は高い方が溶質除去率は向上するが、運転に必要なエネルギーも増加すること、また、複合半透膜の耐久性を考慮すると、複合半透膜に被処理水を透過する際の操作圧力は、０．５ＭＰａ以上１０ＭＰａ以下が好ましい。このとき、膜の透過水量が多いほど、同じ透過水量を得るのに必要な操作圧力を下げることができ、省エネルギーとなるため好ましい。十分に省エネルギーで運転するには、塩素接触前の初期膜透過流束が０．９５ｍ３／ｍ２／ｄ以上であることが好ましく、１．０ｍ３／ｍ２／ｄ以上であることがより好ましい。また、膜の溶質除去性能が高いほど、操作圧力を下げても水質が確保できる。十分な水質を担保するために、塩素接触前の初期塩除去率は、９９．７５％以上が好ましい。さらに、オペレーションミスにより漏洩した塩素が膜と接触しても実用に耐えるためには、実施例記載の耐塩素性試験前後の塩透過率比（ＳＰ比）が２．００以下であることが好ましい。供給水温度は、高くなると溶質除去率が低下するが、低くなるにしたがい膜透過流束も減少するので、５～４５℃以下が好ましい。また、供給水のｐＨが高くなると、海水などの高溶質濃度の供給水の場合、マグネシウムなどのスケールが発生する恐れがあり、また、高ｐＨ運転による膜の劣化が懸念されるため、中性領域での運転が好ましい。
The higher the operating pressure of the fluid separation device, the better the solute removal rate, but the energy required for operation also increases.Also, considering the durability of the composite semipermeable membrane, it is necessary to The operating pressure during permeation is preferably 0.5 MPa or more and 10 MPa or less. At this time, it is preferable that the amount of water permeated through the membrane is larger, since the operating pressure required to obtain the same amount of water permeated can be lowered, resulting in energy savings. In order to operate with sufficient energy savings, the initial membrane permeation flux before contact with chlorine is preferably 0.95 m 3 /m 2 /d or more, and more preferably 1.0 m 3 /m 2 /d or more. preferable. Furthermore, the higher the solute removal performance of the membrane, the better the water quality can be ensured even if the operating pressure is lowered. In order to ensure sufficient water quality, the initial salt removal rate before contact with chlorine is preferably 99.75% or more. Furthermore, in order to withstand practical use even if chlorine leaked due to an operational error comes into contact with the membrane, it is preferable that the salt permeability ratio (SP ratio) before and after the chlorine resistance test described in the example is 2.00 or less. . As the temperature of the feed water increases, the solute removal rate decreases, but as the temperature decreases, the membrane permeation flux also decreases, so it is preferably 5 to 45°C or less. In addition, when the pH of the feed water increases, scales such as magnesium may occur in feed water with a high solute concentration such as seawater, and there is a concern that membrane deterioration due to high pH operation may occur. Driving in the area is preferred.
以下に具体的な実施例を挙げて本発明を説明するが、本発明はこれらの実施例により何ら限定されるものではない。
下記で得られた複合半透膜について性能評価は以下のとおり行った。 The present invention will be described below with reference to specific examples, but the present invention is not limited to these examples in any way.
Performance evaluation of the composite semipermeable membrane obtained below was performed as follows.
下記で得られた複合半透膜について性能評価は以下のとおり行った。 The present invention will be described below with reference to specific examples, but the present invention is not limited to these examples in any way.
Performance evaluation of the composite semipermeable membrane obtained below was performed as follows.
（ｉ）塩除去率の測定
直径７５ｍｍの円形に切り出した膜を、膜評価セルにセットした。温度２５℃、ｐＨ６．５に調整したＴＤＳ濃度３．５％の海水を操作圧力５．５ＭＰａで供給して、３時間運転して安定化した後の透過水を採取した。得られた透過水のＴＤＳ濃度を電気伝導度から求めて、下記式（１）により塩除去率を求めた。
塩除去率（％）＝１００×｛１－（透過水中のＴＤＳ濃度／供給水中のＴＤＳ濃度）｝ ・・・式（１）
なお、小数点第３位を四捨五入した値を用いた。 (i) Measurement of salt removal rate A membrane cut into a circle with a diameter of 75 mm was set in a membrane evaluation cell. Seawater with a TDS concentration of 3.5% adjusted to a temperature of 25° C. and a pH of 6.5 was supplied at an operating pressure of 5.5 MPa, and the permeated water was collected after stabilizing the operation for 3 hours. The TDS concentration of the obtained permeated water was determined from the electrical conductivity, and the salt removal rate was determined using the following formula (1).
Salt removal rate (%) = 100 x {1-(TDS concentration in permeated water/TDS concentration in feed water)} ...Formula (1)
Note that the value rounded to the third decimal place was used.
直径７５ｍｍの円形に切り出した膜を、膜評価セルにセットした。温度２５℃、ｐＨ６．５に調整したＴＤＳ濃度３．５％の海水を操作圧力５．５ＭＰａで供給して、３時間運転して安定化した後の透過水を採取した。得られた透過水のＴＤＳ濃度を電気伝導度から求めて、下記式（１）により塩除去率を求めた。
塩除去率（％）＝１００×｛１－（透過水中のＴＤＳ濃度／供給水中のＴＤＳ濃度）｝ ・・・式（１）
なお、小数点第３位を四捨五入した値を用いた。 (i) Measurement of salt removal rate A membrane cut into a circle with a diameter of 75 mm was set in a membrane evaluation cell. Seawater with a TDS concentration of 3.5% adjusted to a temperature of 25° C. and a pH of 6.5 was supplied at an operating pressure of 5.5 MPa, and the permeated water was collected after stabilizing the operation for 3 hours. The TDS concentration of the obtained permeated water was determined from the electrical conductivity, and the salt removal rate was determined using the following formula (1).
Salt removal rate (%) = 100 x {1-(TDS concentration in permeated water/TDS concentration in feed water)} ...Formula (1)
Note that the value rounded to the third decimal place was used.
（ｉｉ）膜透過流束の測定
上述の「（ｉ）塩除去率の測定」に記載の条件で得られた、膜面１平方メートル当たりの１日の透水量（ｍ３）から、膜透過流束（ｍ３／ｍ２／ｄ）を算出した。 (ii) Measurement of membrane permeation flux The membrane permeation flux is determined from the daily water permeation amount (m 3 ) per 1 square meter of membrane surface obtained under the conditions described in "(i) Measurement of salt removal rate" above. The bundle (m 3 /m 2 /d) was calculated.
上述の「（ｉ）塩除去率の測定」に記載の条件で得られた、膜面１平方メートル当たりの１日の透水量（ｍ３）から、膜透過流束（ｍ３／ｍ２／ｄ）を算出した。 (ii) Measurement of membrane permeation flux The membrane permeation flux is determined from the daily water permeation amount (m 3 ) per 1 square meter of membrane surface obtained under the conditions described in "(i) Measurement of salt removal rate" above. The bundle (m 3 /m 2 /d) was calculated.
（ｉｉｉ）塩素劣化試験
複合半透膜を、ｐＨ７．０に調整した１００ｍｇ／Ｌ次亜塩素酸ナトリウム水溶液に２５℃雰囲気下、２４時間浸漬した。続いて、複合半透膜を１０００ｍｇ／Ｌ亜硫酸水素ナトリウム水溶液に１０分浸漬した後、水で十分に洗浄し、塩素劣化試験後の複合半透膜を得た。耐塩素性は浸漬前後での塩透過率比（ＳＰ比）から求めた。
ＳＰ比＝（１００－浸漬後の塩除去率）／（１００－浸漬前の塩除去率）｝ ・・・式（２）
通常、複合半透膜は塩素浸漬により塩除去率が低下する。ＳＰ比が１．００より大きくなるほど、塩素浸漬により複合半透膜の塩除去率が低下していることを意味する。 (iii) Chlorine deterioration test The composite semipermeable membrane was immersed in a 100 mg/L sodium hypochlorite aqueous solution adjusted to pH 7.0 in an atmosphere of 25° C. for 24 hours. Subsequently, the composite semipermeable membrane was immersed in a 1000 mg/L sodium bisulfite aqueous solution for 10 minutes, and then thoroughly washed with water to obtain a composite semipermeable membrane after a chlorine deterioration test. Chlorine resistance was determined from the salt permeability ratio (SP ratio) before and after immersion.
SP ratio = (100-salt removal rate after immersion)/(100-salt removal rate before immersion)}...Equation (2)
Normally, the salt removal rate of composite semipermeable membranes decreases when immersed in chlorine. As the SP ratio becomes larger than 1.00, it means that the salt removal rate of the composite semipermeable membrane decreases due to chlorine immersion.
複合半透膜を、ｐＨ７．０に調整した１００ｍｇ／Ｌ次亜塩素酸ナトリウム水溶液に２５℃雰囲気下、２４時間浸漬した。続いて、複合半透膜を１０００ｍｇ／Ｌ亜硫酸水素ナトリウム水溶液に１０分浸漬した後、水で十分に洗浄し、塩素劣化試験後の複合半透膜を得た。耐塩素性は浸漬前後での塩透過率比（ＳＰ比）から求めた。
ＳＰ比＝（１００－浸漬後の塩除去率）／（１００－浸漬前の塩除去率）｝ ・・・式（２）
通常、複合半透膜は塩素浸漬により塩除去率が低下する。ＳＰ比が１．００より大きくなるほど、塩素浸漬により複合半透膜の塩除去率が低下していることを意味する。 (iii) Chlorine deterioration test The composite semipermeable membrane was immersed in a 100 mg/L sodium hypochlorite aqueous solution adjusted to pH 7.0 in an atmosphere of 25° C. for 24 hours. Subsequently, the composite semipermeable membrane was immersed in a 1000 mg/L sodium bisulfite aqueous solution for 10 minutes, and then thoroughly washed with water to obtain a composite semipermeable membrane after a chlorine deterioration test. Chlorine resistance was determined from the salt permeability ratio (SP ratio) before and after immersion.
SP ratio = (100-salt removal rate after immersion)/(100-salt removal rate before immersion)}...Equation (2)
Normally, the salt removal rate of composite semipermeable membranes decreases when immersed in chlorine. As the SP ratio becomes larger than 1.00, it means that the salt removal rate of the composite semipermeable membrane decreases due to chlorine immersion.
（ｉｖ）突起の平均厚み、突起の平均数密度の測定
複合半透膜を３ｃｍ×３ｃｍ角に切り出し、２５℃の蒸留水で２４時間洗浄した。これを凍結超薄切片法で処理、すなわち複合半透膜の膜面方向に垂直に切断した後、得られた超薄切片を、透過型電子顕微鏡を用いて断面写真を撮影した。透過型電子顕微鏡により撮影した断面写真を、画像解析ソフトＩｍａｇｅ Ｊに取り込んだ。上述した方法で、突起上部及び下部の平均厚みを測定した。さらに、突起の数を数え、突起の平均数密度を求めた。 (iv) Measurement of average thickness of protrusions and average number density of protrusions The composite semipermeable membrane was cut into a 3 cm x 3 cm square and washed with distilled water at 25° C. for 24 hours. This was processed using a frozen ultra-thin section method, that is, cut perpendicularly to the membrane surface direction of the composite semipermeable membrane, and a cross-sectional photograph of the obtained ultra-thin section was taken using a transmission electron microscope. A cross-sectional photograph taken with a transmission electron microscope was imported into image analysis software Image J. The average thickness of the upper and lower parts of the protrusion was measured using the method described above. Furthermore, the number of protrusions was counted and the average number density of protrusions was determined.
複合半透膜を３ｃｍ×３ｃｍ角に切り出し、２５℃の蒸留水で２４時間洗浄した。これを凍結超薄切片法で処理、すなわち複合半透膜の膜面方向に垂直に切断した後、得られた超薄切片を、透過型電子顕微鏡を用いて断面写真を撮影した。透過型電子顕微鏡により撮影した断面写真を、画像解析ソフトＩｍａｇｅ Ｊに取り込んだ。上述した方法で、突起上部及び下部の平均厚みを測定した。さらに、突起の数を数え、突起の平均数密度を求めた。 (iv) Measurement of average thickness of protrusions and average number density of protrusions The composite semipermeable membrane was cut into a 3 cm x 3 cm square and washed with distilled water at 25° C. for 24 hours. This was processed using a frozen ultra-thin section method, that is, cut perpendicularly to the membrane surface direction of the composite semipermeable membrane, and a cross-sectional photograph of the obtained ultra-thin section was taken using a transmission electron microscope. A cross-sectional photograph taken with a transmission electron microscope was imported into image analysis software Image J. The average thickness of the upper and lower parts of the protrusion was measured using the method described above. Furthermore, the number of protrusions was counted and the average number density of protrusions was determined.
（ｖ）突起のＯ／Ｎ比の測定
凍結超薄切片法で得られた超薄切片を、電界放出形透過電子顕微鏡（ＪＥＯＬ製 ＪＥＭ－２１００Ｆ）にて図４に示すように突起を拡大して観察した。拡大した突起（凸部６）において、突起の頂点を通る、ＴＥＭ－ＥＥＬＳ測定位置Ｍにて、ＥＥＬＳ検出器（Ｇａｔａｎ製Ｔｒｉｄｉｅｍ）を用いて加速電圧２００ｋＶ、エネルギー分解能 ０．８ｅＶ ＦＷＨＭ）、－１７５℃の条件でＯ及びＮを測定した。測定は１つの断面において、見かけ高さが１０点平均面粗さの５分の１以上である突起から無作為に３つを選択した。同様の測定を無作為に選択した３つの断面について行い、Ｏ／Ｎ比の相加平均値を算出し、突起の見かけ高さＰａｈの２～２５％の範囲でのＯ／Ｎ比の平均値であるｘ、突起の見かけ高さＰａｈの７５～９８％の範囲でのＯ／Ｎ比の平均値であるｙを求めた。 (v) Measurement of O/N ratio of protrusions Ultra-thin sections obtained by frozen ultra-thin sectioning were enlarged using a field emission transmission electron microscope (JEM-2100F manufactured by JEOL) as shown in Figure 4. I observed it. In the enlarged protrusion (convex part 6), at the TEM-EELS measurement position M passing through the apex of the protrusion, an EELS detector (Tridiem manufactured by Gatan) was used at an acceleration voltage of 200 kV, energy resolution of 0.8 eV FWHM), -175 O and N were measured under the conditions of ℃. For the measurement, three protrusions were randomly selected from among the protrusions whose apparent height was one-fifth or more of the 10-point average surface roughness in one cross section. Similar measurements were performed on three randomly selected cross sections, and the arithmetic average value of the O/N ratio was calculated, and the average value of the O/N ratio in the range of 2 to 25% of the apparent height Pah of the projection. , x, and y, which is the average value of the O/N ratio in the range of 75 to 98% of the apparent height Pah of the protrusion, were determined.
凍結超薄切片法で得られた超薄切片を、電界放出形透過電子顕微鏡（ＪＥＯＬ製 ＪＥＭ－２１００Ｆ）にて図４に示すように突起を拡大して観察した。拡大した突起（凸部６）において、突起の頂点を通る、ＴＥＭ－ＥＥＬＳ測定位置Ｍにて、ＥＥＬＳ検出器（Ｇａｔａｎ製Ｔｒｉｄｉｅｍ）を用いて加速電圧２００ｋＶ、エネルギー分解能 ０．８ｅＶ ＦＷＨＭ）、－１７５℃の条件でＯ及びＮを測定した。測定は１つの断面において、見かけ高さが１０点平均面粗さの５分の１以上である突起から無作為に３つを選択した。同様の測定を無作為に選択した３つの断面について行い、Ｏ／Ｎ比の相加平均値を算出し、突起の見かけ高さＰａｈの２～２５％の範囲でのＯ／Ｎ比の平均値であるｘ、突起の見かけ高さＰａｈの７５～９８％の範囲でのＯ／Ｎ比の平均値であるｙを求めた。 (v) Measurement of O/N ratio of protrusions Ultra-thin sections obtained by frozen ultra-thin sectioning were enlarged using a field emission transmission electron microscope (JEM-2100F manufactured by JEOL) as shown in Figure 4. I observed it. In the enlarged protrusion (convex part 6), at the TEM-EELS measurement position M passing through the apex of the protrusion, an EELS detector (Tridiem manufactured by Gatan) was used at an acceleration voltage of 200 kV, energy resolution of 0.8 eV FWHM), -175 O and N were measured under the conditions of ℃. For the measurement, three protrusions were randomly selected from among the protrusions whose apparent height was one-fifth or more of the 10-point average surface roughness in one cross section. Similar measurements were performed on three randomly selected cross sections, and the arithmetic average value of the O/N ratio was calculated, and the average value of the O/N ratio in the range of 2 to 25% of the apparent height Pah of the projection. , x, and y, which is the average value of the O/N ratio in the range of 75 to 98% of the apparent height Pah of the protrusion, were determined.
［参考例１］
基材であるポリエステル不織布（通気量２．０ｃｃ／ｃｍ２／ｓｅｃ）上に、ポリスルホンＵＤＥＬ Ｐ－３５００（ソルベイアドバンストポリマーズ株式会社製）の１８．０質量％ＤＭＦ溶液を２５℃の条件下で２００μｍの厚みでキャストした。これをただちに純水中に浸漬し、５分間放置して凝固させ、基材と微多孔性支持層とを有する支持膜を作製した。基材と微多孔性支持層の厚みの合計は、１５０μｍであった。 [Reference example 1]
A 18.0% by mass DMF solution of polysulfone UDEL P-3500 (manufactured by Solvay Advanced Polymers Co., Ltd.) was applied to a 200 μm thick polyester nonwoven fabric (airflow rate: 2.0 cc/cm 2 /sec) as a base material at 25°C. It was cast to a thickness of . This was immediately immersed in pure water and allowed to stand for 5 minutes to solidify, thereby producing a support membrane having a base material and a microporous support layer. The total thickness of the base material and the microporous support layer was 150 μm.
基材であるポリエステル不織布（通気量２．０ｃｃ／ｃｍ２／ｓｅｃ）上に、ポリスルホンＵＤＥＬ Ｐ－３５００（ソルベイアドバンストポリマーズ株式会社製）の１８．０質量％ＤＭＦ溶液を２５℃の条件下で２００μｍの厚みでキャストした。これをただちに純水中に浸漬し、５分間放置して凝固させ、基材と微多孔性支持層とを有する支持膜を作製した。基材と微多孔性支持層の厚みの合計は、１５０μｍであった。 [Reference example 1]
A 18.0% by mass DMF solution of polysulfone UDEL P-3500 (manufactured by Solvay Advanced Polymers Co., Ltd.) was applied to a 200 μm thick polyester nonwoven fabric (airflow rate: 2.0 cc/cm 2 /sec) as a base material at 25°C. It was cast to a thickness of . This was immediately immersed in pure water and allowed to stand for 5 minutes to solidify, thereby producing a support membrane having a base material and a microporous support layer. The total thickness of the base material and the microporous support layer was 150 μm.
［実施例１］
３．０質量％ｍ－フェニレンジアミン水溶液中に、参考例１で得られた支持膜を２分浸漬した。該支持膜を垂直方向にゆっくりと引き上げ、エアーノズルから窒素を吹き付けることで、支持膜表面から余分な水溶液を取り除いた。４０℃に制御した環境で、０．１６質量％ＴＭＣを含む４０℃のｎ－デカン溶液を、支持膜の表面が完全に濡れるように塗布した。次に、１２０℃のオーブンで支持膜を加熱し、その後、膜から余分な溶液を除去するために、膜を垂直にして液切りを行って、送風機を使い２０℃の空気を吹き付けて乾燥させた。乾燥した膜を、アミド基を含む化合物として１０質量％Ｎ，Ｎ－ジメチルホルムアミド水溶液に２５℃にて２分浸漬させた。その後、膜を９０℃の純水で洗浄することで、実施例１の複合半透膜を得た。実施例１の複合半透膜の突起の高さは１０２ｎｍであった。 [Example 1]
The support membrane obtained in Reference Example 1 was immersed in a 3.0% by mass aqueous m-phenylenediamine solution for 2 minutes. The support membrane was slowly pulled up vertically and nitrogen was blown from an air nozzle to remove excess aqueous solution from the surface of the support membrane. In an environment controlled at 40°C, a 40°C n-decane solution containing 0.16% by mass of TMC was applied so that the surface of the support membrane was completely wetted. Next, the supporting membrane was heated in an oven at 120°C, and then, in order to remove excess solution from the membrane, the membrane was placed vertically to drain the liquid, and then dried by blowing air at 20°C using a blower. Ta. The dried membrane was immersed for 2 minutes at 25° C. in a 10% by mass aqueous solution of N,N-dimethylformamide as a compound containing an amide group. Thereafter, the composite semipermeable membrane of Example 1 was obtained by washing the membrane with 90°C pure water. The height of the protrusions of the composite semipermeable membrane of Example 1 was 102 nm.
３．０質量％ｍ－フェニレンジアミン水溶液中に、参考例１で得られた支持膜を２分浸漬した。該支持膜を垂直方向にゆっくりと引き上げ、エアーノズルから窒素を吹き付けることで、支持膜表面から余分な水溶液を取り除いた。４０℃に制御した環境で、０．１６質量％ＴＭＣを含む４０℃のｎ－デカン溶液を、支持膜の表面が完全に濡れるように塗布した。次に、１２０℃のオーブンで支持膜を加熱し、その後、膜から余分な溶液を除去するために、膜を垂直にして液切りを行って、送風機を使い２０℃の空気を吹き付けて乾燥させた。乾燥した膜を、アミド基を含む化合物として１０質量％Ｎ，Ｎ－ジメチルホルムアミド水溶液に２５℃にて２分浸漬させた。その後、膜を９０℃の純水で洗浄することで、実施例１の複合半透膜を得た。実施例１の複合半透膜の突起の高さは１０２ｎｍであった。 [Example 1]
The support membrane obtained in Reference Example 1 was immersed in a 3.0% by mass aqueous m-phenylenediamine solution for 2 minutes. The support membrane was slowly pulled up vertically and nitrogen was blown from an air nozzle to remove excess aqueous solution from the surface of the support membrane. In an environment controlled at 40°C, a 40°C n-decane solution containing 0.16% by mass of TMC was applied so that the surface of the support membrane was completely wetted. Next, the supporting membrane was heated in an oven at 120°C, and then, in order to remove excess solution from the membrane, the membrane was placed vertically to drain the liquid, and then dried by blowing air at 20°C using a blower. Ta. The dried membrane was immersed for 2 minutes at 25° C. in a 10% by mass aqueous solution of N,N-dimethylformamide as a compound containing an amide group. Thereafter, the composite semipermeable membrane of Example 1 was obtained by washing the membrane with 90°C pure water. The height of the protrusions of the composite semipermeable membrane of Example 1 was 102 nm.
［実施例２］
オーブンの温度を１５０℃とし、空気を吹き付けて乾燥後に５℃の３０．０質量％Ｎ，Ｎ－ジメチルホルムアミド水溶液に２分浸漬させた以外は、実施例１と同様にして、実施例２の複合半透膜を得た。 [Example 2]
Example 2 was prepared in the same manner as in Example 1, except that the oven temperature was set to 150°C, and after drying by blowing air, it was immersed in a 30.0 mass% N,N-dimethylformamide aqueous solution at 5°C for 2 minutes. A composite semipermeable membrane was obtained.
オーブンの温度を１５０℃とし、空気を吹き付けて乾燥後に５℃の３０．０質量％Ｎ，Ｎ－ジメチルホルムアミド水溶液に２分浸漬させた以外は、実施例１と同様にして、実施例２の複合半透膜を得た。 [Example 2]
Example 2 was prepared in the same manner as in Example 1, except that the oven temperature was set to 150°C, and after drying by blowing air, it was immersed in a 30.0 mass% N,N-dimethylformamide aqueous solution at 5°C for 2 minutes. A composite semipermeable membrane was obtained.
［実施例３］
空気を吹き付けて乾燥後に１０℃の１０．０質量％Ｎ，Ｎ－ジメチルホルムアミド水溶液に２分浸漬させた以外は、実施例１と同様にして、実施例３の複合半透膜を得た。 [Example 3]
A composite semipermeable membrane of Example 3 was obtained in the same manner as in Example 1, except that after drying by blowing air, it was immersed in a 10.0 mass % N,N-dimethylformamide aqueous solution at 10° C. for 2 minutes.
空気を吹き付けて乾燥後に１０℃の１０．０質量％Ｎ，Ｎ－ジメチルホルムアミド水溶液に２分浸漬させた以外は、実施例１と同様にして、実施例３の複合半透膜を得た。 [Example 3]
A composite semipermeable membrane of Example 3 was obtained in the same manner as in Example 1, except that after drying by blowing air, it was immersed in a 10.0 mass % N,N-dimethylformamide aqueous solution at 10° C. for 2 minutes.
［実施例４］
接触させるＮ，Ｎ－ジメチルホルムアミド水溶液の温度を４５℃にした以外は、実施例１と同様にして、実施例４の複合半透膜を得た。 [Example 4]
A composite semipermeable membrane of Example 4 was obtained in the same manner as in Example 1, except that the temperature of the N,N-dimethylformamide aqueous solution brought into contact was 45°C.
接触させるＮ，Ｎ－ジメチルホルムアミド水溶液の温度を４５℃にした以外は、実施例１と同様にして、実施例４の複合半透膜を得た。 [Example 4]
A composite semipermeable membrane of Example 4 was obtained in the same manner as in Example 1, except that the temperature of the N,N-dimethylformamide aqueous solution brought into contact was 45°C.
［実施例５］
ｍ－フェニレンジアミン水溶液を６．０質量％にした以外は、実施例１と同様にして、実施例５の複合半透膜を得た。 [Example 5]
A composite semipermeable membrane of Example 5 was obtained in the same manner as in Example 1 except that the m-phenylenediamine aqueous solution was changed to 6.0% by mass.
ｍ－フェニレンジアミン水溶液を６．０質量％にした以外は、実施例１と同様にして、実施例５の複合半透膜を得た。 [Example 5]
A composite semipermeable membrane of Example 5 was obtained in the same manner as in Example 1 except that the m-phenylenediamine aqueous solution was changed to 6.0% by mass.
［実施例６］
接触させるＮ，Ｎ－ジメチルホルムアミド水溶液の濃度を１．０質量％にした以外は、実施例２と同様にして、実施例６の複合半透膜を得た。 [Example 6]
A composite semipermeable membrane of Example 6 was obtained in the same manner as in Example 2, except that the concentration of the N,N-dimethylformamide aqueous solution brought into contact was 1.0% by mass.
接触させるＮ，Ｎ－ジメチルホルムアミド水溶液の濃度を１．０質量％にした以外は、実施例２と同様にして、実施例６の複合半透膜を得た。 [Example 6]
A composite semipermeable membrane of Example 6 was obtained in the same manner as in Example 2, except that the concentration of the N,N-dimethylformamide aqueous solution brought into contact was 1.0% by mass.
［実施例７］
接触させるアミド基を含む化合物の含有する溶液をεカプロラクタムに変更して１０．０質量％εカプロラクタム水溶液とした以外は、実施例１と同様にして、実施例７の複合半透膜を得た。 [Example 7]
A composite semipermeable membrane of Example 7 was obtained in the same manner as in Example 1, except that the solution containing the compound containing an amide group to be contacted was changed to ε-caprolactam to obtain a 10.0% by mass ε-caprolactam aqueous solution. .
接触させるアミド基を含む化合物の含有する溶液をεカプロラクタムに変更して１０．０質量％εカプロラクタム水溶液とした以外は、実施例１と同様にして、実施例７の複合半透膜を得た。 [Example 7]
A composite semipermeable membrane of Example 7 was obtained in the same manner as in Example 1, except that the solution containing the compound containing an amide group to be contacted was changed to ε-caprolactam to obtain a 10.0% by mass ε-caprolactam aqueous solution. .
［実施例８］
塗布するＴＭＣのｎ－デカン溶液の温度を６５℃にした以外は、実施例２と同様にして、実施例８の複合半透膜を得た。 [Example 8]
A composite semipermeable membrane of Example 8 was obtained in the same manner as in Example 2, except that the temperature of the n-decane solution of TMC to be applied was 65°C.
塗布するＴＭＣのｎ－デカン溶液の温度を６５℃にした以外は、実施例２と同様にして、実施例８の複合半透膜を得た。 [Example 8]
A composite semipermeable membrane of Example 8 was obtained in the same manner as in Example 2, except that the temperature of the n-decane solution of TMC to be applied was 65°C.
［実施例９］
多官能芳香族酸ハロゲン化物溶液として、０．１６質量％ＴＭＣと０．０１６質量％のイソフタル酸クロリドを含む４０℃のｎ－デカン溶液を用いた以外は、実施例１と同様にして、実施例９の複合半透膜を得た。 [Example 9]
The procedure was carried out in the same manner as in Example 1, except that a 40°C n-decane solution containing 0.16% by mass TMC and 0.016% by mass isophthalic acid chloride was used as the polyfunctional aromatic acid halide solution. A composite semipermeable membrane of Example 9 was obtained.
多官能芳香族酸ハロゲン化物溶液として、０．１６質量％ＴＭＣと０．０１６質量％のイソフタル酸クロリドを含む４０℃のｎ－デカン溶液を用いた以外は、実施例１と同様にして、実施例９の複合半透膜を得た。 [Example 9]
The procedure was carried out in the same manner as in Example 1, except that a 40°C n-decane solution containing 0.16% by mass TMC and 0.016% by mass isophthalic acid chloride was used as the polyfunctional aromatic acid halide solution. A composite semipermeable membrane of Example 9 was obtained.
［比較例１］
アミド基を含む化合物を含有する溶液に乾燥した膜を接触させる工程を行わなかったこと以外は、実施例５と同様にして、比較例１の複合半透膜を得た。 [Comparative example 1]
A composite semipermeable membrane of Comparative Example 1 was obtained in the same manner as in Example 5, except that the step of bringing the dried membrane into contact with a solution containing a compound containing an amide group was not performed.
アミド基を含む化合物を含有する溶液に乾燥した膜を接触させる工程を行わなかったこと以外は、実施例５と同様にして、比較例１の複合半透膜を得た。 [Comparative example 1]
A composite semipermeable membrane of Comparative Example 1 was obtained in the same manner as in Example 5, except that the step of bringing the dried membrane into contact with a solution containing a compound containing an amide group was not performed.
［比較例２］
ＴＭＣ０．１６質量％を含む４０℃のｎ－デカン溶液を支持膜の表面が完全に濡れるように塗布した後、さらにＴＭＣ０．３２重量％を含むｎ－デカン溶液を支持膜に塗布してから１２０℃のオーブンで加熱した以外は、比較例１と同様にして、比較例２の複合半透膜を得た。 [Comparative example 2]
After applying a 40°C n-decane solution containing 0.16% by weight of TMC so that the surface of the support membrane was completely wet, an n-decane solution containing 0.32% by weight of TMC was further applied to the support membrane, and then 120% A composite semipermeable membrane of Comparative Example 2 was obtained in the same manner as Comparative Example 1 except that it was heated in an oven at .degree.
ＴＭＣ０．１６質量％を含む４０℃のｎ－デカン溶液を支持膜の表面が完全に濡れるように塗布した後、さらにＴＭＣ０．３２重量％を含むｎ－デカン溶液を支持膜に塗布してから１２０℃のオーブンで加熱した以外は、比較例１と同様にして、比較例２の複合半透膜を得た。 [Comparative example 2]
After applying a 40°C n-decane solution containing 0.16% by weight of TMC so that the surface of the support membrane was completely wet, an n-decane solution containing 0.32% by weight of TMC was further applied to the support membrane, and then 120% A composite semipermeable membrane of Comparative Example 2 was obtained in the same manner as Comparative Example 1 except that it was heated in an oven at .degree.
（比較例３）
ＴＭＣ溶液の溶媒をイソオクタンとし、溶液の温度を２５℃として、２５℃に制御した環境で塗布し、さらにオーブンの温度を１５０℃にした以外は、比較例１と同様にして、比較例３の複合半透膜を得た。 (Comparative example 3)
Comparative Example 3 was carried out in the same manner as Comparative Example 1, except that the solvent for the TMC solution was isooctane, the solution temperature was 25°C, the coating was carried out in an environment controlled at 25°C, and the oven temperature was 150°C. A composite semipermeable membrane was obtained.
ＴＭＣ溶液の溶媒をイソオクタンとし、溶液の温度を２５℃として、２５℃に制御した環境で塗布し、さらにオーブンの温度を１５０℃にした以外は、比較例１と同様にして、比較例３の複合半透膜を得た。 (Comparative example 3)
Comparative Example 3 was carried out in the same manner as Comparative Example 1, except that the solvent for the TMC solution was isooctane, the solution temperature was 25°C, the coating was carried out in an environment controlled at 25°C, and the oven temperature was 150°C. A composite semipermeable membrane was obtained.
（比較例４）
１２０℃のオーブンに入れる工程を省略し、ＴＭＣのｎ－デカン溶液の温度を２５℃とし、２５℃に制御した環境で塗布した以外は、比較例１と同様にして、比較例４の複合半透膜を得た。 (Comparative example 4)
The composite half of Comparative Example 4 was prepared in the same manner as Comparative Example 1, except that the step of placing it in an oven at 120°C was omitted, the temperature of the TMC n-decane solution was 25°C, and the coating was performed in an environment controlled at 25°C. A permeable membrane was obtained.
１２０℃のオーブンに入れる工程を省略し、ＴＭＣのｎ－デカン溶液の温度を２５℃とし、２５℃に制御した環境で塗布した以外は、比較例１と同様にして、比較例４の複合半透膜を得た。 (Comparative example 4)
The composite half of Comparative Example 4 was prepared in the same manner as Comparative Example 1, except that the step of placing it in an oven at 120°C was omitted, the temperature of the TMC n-decane solution was 25°C, and the coating was performed in an environment controlled at 25°C. A permeable membrane was obtained.
（比較例５）
空気を吹き付けて乾燥後に２５℃の１質量％リン酸トリブチル水溶液に２分浸漬した以外は、比較例１と同様にして、比較例５の複合半透膜を得た。 (Comparative example 5)
A composite semipermeable membrane of Comparative Example 5 was obtained in the same manner as Comparative Example 1, except that after drying by blowing air, it was immersed in a 1% by mass tributyl phosphate aqueous solution at 25° C. for 2 minutes.
空気を吹き付けて乾燥後に２５℃の１質量％リン酸トリブチル水溶液に２分浸漬した以外は、比較例１と同様にして、比較例５の複合半透膜を得た。 (Comparative example 5)
A composite semipermeable membrane of Comparative Example 5 was obtained in the same manner as Comparative Example 1, except that after drying by blowing air, it was immersed in a 1% by mass tributyl phosphate aqueous solution at 25° C. for 2 minutes.
（比較例６）
空気を吹き付けて乾燥後に２５℃の１０質量％イソプロピルアルコール水溶液に２分浸漬した以外は、比較例１と同様にして、比較例６の複合半透膜を得た。 (Comparative example 6)
A composite semipermeable membrane of Comparative Example 6 was obtained in the same manner as Comparative Example 1, except that after drying by blowing air, it was immersed in a 10% by mass isopropyl alcohol aqueous solution at 25° C. for 2 minutes.
空気を吹き付けて乾燥後に２５℃の１０質量％イソプロピルアルコール水溶液に２分浸漬した以外は、比較例１と同様にして、比較例６の複合半透膜を得た。 (Comparative example 6)
A composite semipermeable membrane of Comparative Example 6 was obtained in the same manner as Comparative Example 1, except that after drying by blowing air, it was immersed in a 10% by mass isopropyl alcohol aqueous solution at 25° C. for 2 minutes.
以上の結果を表１に示す。実施例１～９より、本実施形態の複合半透膜は、高い透水性及び塩除去性を有し、かつ、塩素接触後の塩除去性の変化が小さいことが分かる。
The above results are shown in Table 1. From Examples 1 to 9, it can be seen that the composite semipermeable membrane of this embodiment has high water permeability and salt removability, and the change in salt removability after contact with chlorine is small.
本発明を特定の態様を参照して詳細に説明したが、本発明の精神と範囲を離れることなく様々な変更および修正が可能であることは、当業者にとって明らかである。なお、本出願は、２０２２年８月３１日付けで出願された日本特許出願（特願２０２２－１３７５０１）に基づいており、その全体が引用により援用される。また、ここに引用されるすべての参照は全体として取り込まれる。
Although the invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application (Japanese Patent Application No. 2022-137501) filed on August 31, 2022, and is incorporated by reference in its entirety. Additionally, all references cited herein are incorporated in their entirety.
１ 複合半透膜
２ 基材
３ 微多孔性支持層
４ 分離機能層
５ 薄膜
６ 凸部
Ａ 粗さ曲線の平均線
Ｙｐ１～５ 平均線Ａから最も高い山頂から５番目までの山頂の標高
Ｙｖ１～５ 平均線Ａから最も低い谷底から５番目までの谷底の標高
Ｌ 基準長さ
Ｂ 突起の頂点の位置
Ｚ 平均線Ａからの距離がｄである位置
ｄ 距離ｄ１とｄ２の平均値
ｄ１ 平均線Ａから突起左側の凹部の頂点までの距離
ｄ２ 平均線Ａから突起右側の凹部の頂点までの距離
ｈ 平均線Ａから突起の頂点までの距離
Ｐｈ 突起の高さ
Ｔ２５ 突起の高さの２～２５％の範囲における薄膜の平均厚み
Ｔ９８ 突起の高さ７５～９８％の範囲における薄膜の平均厚み
Ｐａｈ 突起の見かけ高さ
Ｍ ＴＥＭ－ＥＥＬＳ測定位置 1 Compositesemipermeable membrane 2 Base material 3 Microporous support layer 4 Separation functional layer 5 Thin film 6 Convex portion A Average line of roughness curve Yp1~5 Elevation of the fifth peak from the highest peak from average line A Yv1~ 5 Elevation L of the fifth valley bottom from the lowest from the average line A Standard length B Position Z of the apex of the protrusion Position d at a distance of d from the average line A Average value d1 of distances d1 and d2 Average line A Distance d2 from the average line A to the apex of the recess on the right side of the protrusion Distance h from the average line A to the apex of the protrusion Ph Height of the protrusion T25 2 to 25% of the height of the protrusion Average thickness of the thin film in the range T98 Average thickness of the thin film in the range of 75% to 98% of the protrusion height Pah Apparent height of the protrusion M TEM-EELS measurement position
２ 基材
３ 微多孔性支持層
４ 分離機能層
５ 薄膜
６ 凸部
Ａ 粗さ曲線の平均線
Ｙｐ１～５ 平均線Ａから最も高い山頂から５番目までの山頂の標高
Ｙｖ１～５ 平均線Ａから最も低い谷底から５番目までの谷底の標高
Ｌ 基準長さ
Ｂ 突起の頂点の位置
Ｚ 平均線Ａからの距離がｄである位置
ｄ 距離ｄ１とｄ２の平均値
ｄ１ 平均線Ａから突起左側の凹部の頂点までの距離
ｄ２ 平均線Ａから突起右側の凹部の頂点までの距離
ｈ 平均線Ａから突起の頂点までの距離
Ｐｈ 突起の高さ
Ｔ２５ 突起の高さの２～２５％の範囲における薄膜の平均厚み
Ｔ９８ 突起の高さ７５～９８％の範囲における薄膜の平均厚み
Ｐａｈ 突起の見かけ高さ
Ｍ ＴＥＭ－ＥＥＬＳ測定位置 1 Composite
Claims (9)
- 微多孔性支持層と、前記微多孔性支持層上に設けられた分離機能層とを有する複合半透膜であって、
前記分離機能層は、架橋芳香族ポリアミドを含有する薄膜で構成される複数の突起を有し、
透過型電子顕微鏡における電子エネルギー損失分光法（ＴＥＭ－ＥＥＬＳ）により測定される下記ｘ及びｙが、ｙ／ｘ≧１．３を満たす、複合半透膜。
ｘ：前記突起の見かけ高さの２～２５％の範囲における酸素原子（Ｏ）／窒素原子（Ｎ）比の平均値
ｙ：前記突起の見かけ高さの７５～９８％の範囲におけるＯ／Ｎ比の平均値 A composite semipermeable membrane having a microporous support layer and a separation functional layer provided on the microporous support layer,
The separation functional layer has a plurality of protrusions made of a thin film containing crosslinked aromatic polyamide,
A composite semipermeable membrane in which the following x and y satisfy y/x≧1.3 as measured by electron energy loss spectroscopy in a transmission electron microscope (TEM-EELS).
x: average value of oxygen atom (O)/nitrogen atom (N) ratio in the range of 2 to 25% of the apparent height of the protrusion y: O/N in the range of 75 to 98% of the apparent height of the protrusion Average value of ratio - 前記ｙがｙ≧０．９０を満たす、請求項１に記載の複合半透膜。 The composite semipermeable membrane according to claim 1, wherein the y satisfies y≧0.90.
- 前記ｘがｘ≧０．５０を満たす、請求項１又は請求項２に記載の複合半透膜。 The composite semipermeable membrane according to claim 1 or 2, wherein the x satisfies x≧0.50.
- 前記分離機能層において、前記突起の高さの２～２５％の範囲における前記薄膜の平均厚みＴ２５に対する、前記突起の高さ７５～９８％の範囲における前記薄膜の平均厚みＴ９８の比（Ｔ９８／Ｔ２５）が０．９５以下である、請求項１又は請求項２に記載の複合半透膜。 In the separation functional layer, the ratio (T98/ The composite semipermeable membrane according to claim 1 or 2, wherein T25) is 0.95 or less.
- 前記分離機能層中で、１０点平均面粗さの５分の１以上の高さを有する突起の平均数密度が１３．０個／μｍ以上である、請求項１又は２に記載の複合半透膜。 The composite half according to claim 1 or 2, wherein the separation functional layer has an average number density of protrusions having a height of 1/5 or more of the 10-point average surface roughness of 13.0 pieces/μm or more. Permeable membrane.
- 前記架橋芳香族ポリアミドが、トリメシン酸クロリドとｍ－フェニレンジアミンの重合物であるポリアミドを含む、請求項１又は２に記載の複合半透膜。 The composite semipermeable membrane according to claim 1 or 2, wherein the crosslinked aromatic polyamide includes a polyamide that is a polymer of trimesic acid chloride and m-phenylenediamine.
- 微多孔性支持層と、前記微多孔性支持層上に設けられた分離機能層とを有する複合半透膜の製造方法であって、
多官能芳香族アミン水溶液と、多官能芳香族酸ハロゲン化物の有機溶媒溶液とを用い、前記微多孔性支持層上で界面重縮合によって架橋芳香族ポリアミドを含有する層を形成する工程と、
架橋芳香族ポリアミドを含有する前記層にアミド基を含む化合物を含有する溶液を接触させる工程と、
を備える複合半透膜の製造方法。 A method for producing a composite semipermeable membrane having a microporous support layer and a separation functional layer provided on the microporous support layer, the method comprising:
forming a layer containing a crosslinked aromatic polyamide on the microporous support layer by interfacial polycondensation using a polyfunctional aromatic amine aqueous solution and an organic solvent solution of a polyfunctional aromatic acid halide;
contacting the layer containing crosslinked aromatic polyamide with a solution containing a compound containing an amide group;
A method for manufacturing a composite semipermeable membrane comprising: - 請求項１又は２に記載の複合半透膜を備えるエレメント。 An element comprising the composite semipermeable membrane according to claim 1 or 2.
- 請求項１又は２に記載の複合半透膜を備える流体分離装置。 A fluid separation device comprising the composite semipermeable membrane according to claim 1 or 2.
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| JP2022-137501 | 2022-08-31 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6312310A (en) * | 1986-07-04 | 1988-01-19 | Toray Ind Inc | Production of semipermeable composite membrane |
| JP2016144794A (en) * | 2015-01-29 | 2016-08-12 | 東レ株式会社 | Composite semipermeable membrane and composite semipermeable element |
| WO2018003943A1 (en) * | 2016-06-29 | 2018-01-04 | 東レ株式会社 | Composite semipermeable membrane and method for producing composite semipermeable membrane |
-
2023
- 2023-08-30 WO PCT/JP2023/031656 patent/WO2024048695A1/en unknown
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6312310A (en) * | 1986-07-04 | 1988-01-19 | Toray Ind Inc | Production of semipermeable composite membrane |
| JP2016144794A (en) * | 2015-01-29 | 2016-08-12 | 東レ株式会社 | Composite semipermeable membrane and composite semipermeable element |
| WO2018003943A1 (en) * | 2016-06-29 | 2018-01-04 | 東レ株式会社 | Composite semipermeable membrane and method for producing composite semipermeable membrane |
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