WO2016052669A1 - Membrane semi-perméable composite - Google Patents

Membrane semi-perméable composite Download PDF

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Publication number
WO2016052669A1
WO2016052669A1 PCT/JP2015/077861 JP2015077861W WO2016052669A1 WO 2016052669 A1 WO2016052669 A1 WO 2016052669A1 JP 2015077861 W JP2015077861 W JP 2015077861W WO 2016052669 A1 WO2016052669 A1 WO 2016052669A1
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Prior art keywords
composite semipermeable
semipermeable membrane
functional layer
separation functional
polyamide
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PCT/JP2015/077861
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English (en)
Japanese (ja)
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慧 加藤
宏治 中▲辻▼
雅和 小岩
智子 光畑
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東レ株式会社
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Priority to JP2015556274A priority Critical patent/JPWO2016052669A1/ja
Publication of WO2016052669A1 publication Critical patent/WO2016052669A1/fr

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    • 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
    • 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
    • B01D69/10—Supported membranes; Membrane supports
    • B01D69/107—Organic support material
    • B01D69/1071—Woven, non-woven or net mesh
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
    • C08G69/26—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids

Definitions

  • the present invention relates to a composite semipermeable membrane having selective removability that selectively removes multivalent ions, agricultural chemicals, and the like and allows permeation of monovalent ions having a small ion radius.
  • This membrane enables salt removal and mineral adjustment from brine and seawater, and salt removal and mineral adjustment in the food field.
  • Membranes used in membrane separation methods include microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, and reverse osmosis membranes. These membranes are, for example, from seawater, brine, and water containing harmful substances. For drinking water, softening of drinking water, food use, production of industrial ultrapure water, wastewater treatment, recovery of valuable materials.
  • composite semipermeable membranes which have an active layer in which a gel layer and a polymer are cross-linked on a support membrane, and monomers are polycondensed on the support membrane.
  • an active layer There are two types, one with an active layer.
  • a composite semipermeable membrane obtained by coating a support membrane with a separation functional layer made of a crosslinked polyamide obtained by polycondensation reaction of a polyfunctional amine and a polyfunctional acid halide has a permeability and a selective separation property. Widely used as a high separation membrane.
  • Nanofiltration membranes are widely used to separate specific substances from mixed solutions of monovalent ions, divalent ions, and organic substances, and nanofiltration membranes composed of aliphatic amines and acid halides have been proposed.
  • the surface of the separation functional layer may be damaged by contact of a flow path material or the like with the separation functional layer.
  • precipitation components such as silica may precipitate on the surface of the separation membrane, thereby damaging the surface of the separation functional layer and causing a decrease in separation performance. is there. Therefore, the separation functional layer is required to have a strength that can sufficiently withstand such a physical external force.
  • Patent Documents 1 and 2 are obtained by reacting a polyfunctional aromatic carboxylic acid chloride with a diamine component of piperazine or a diamine component of piperazine and 4,4′-bipiperidine.
  • a composite nanofiltration membrane made of polyamide is disclosed.
  • Patent Documents 3 and 4 in the composite reverse osmosis membrane and the composite nanofiltration membrane obtained by reacting piperazine and trimesic acid chloride, the composition and concentration at the time of film formation are examined in detail.
  • the objective of this invention is providing the manufacturing method of the composite semipermeable membrane and composite semipermeable membrane element which have high abrasion resistance, and a composite semipermeable membrane.
  • the composite semipermeable membrane of the present invention has the following constitutions (1) to (8).
  • a composite semipermeable membrane comprising a base material and a support membrane comprising a porous support layer provided on the base material, and a polyamide separation functional layer formed on the porous support layer,
  • the polyamide separation functional layer is a polyamide layer obtained from an aliphatic polyfunctional amine and a polyfunctional acid halide, and the amide group ratio represented by the following formula of the aliphatic polyamide in the polyamide separation functional layer is 0.80 or more.
  • a composite semipermeable membrane having a thickness of 10 to 50 nm.
  • the composite semipermeable membrane of the present invention since the polyamide separation functional layer having a specific amide group ratio is provided, a composite semipermeable membrane having high scratch resistance is realized.
  • FIG. 1 is a perspective view showing an example of a separation membrane element.
  • the composite semipermeable membrane of the present invention comprises a base material, a porous support layer provided on the base material, and a polyamide separation functional layer formed on the porous support layer.
  • the polyamide separation functional layer (hereinafter also simply referred to as “separation functional layer”) is a layer responsible for the solute separation function in the composite semipermeable membrane.
  • the separation functional layer is a polyamide layer made from an aliphatic polyfunctional amine and a polyfunctional acid halide.
  • the aliphatic polyfunctional amine is preferably a bifunctional aliphatic amine having two or more amino groups in one molecule.
  • Examples of the bifunctional aliphatic amine include ethylenediamine, N-methylethylenediamine, and N, N′-dimethylethylenediamine.
  • piperazine-based amines and derivatives thereof In view of the stability of performance, it is preferable to use piperazine-based amines and derivatives thereof, and among them, piperazine (hereinafter sometimes referred to as “Pip”) is more preferable.
  • Piperazine hereinafter sometimes referred to as “Pip”
  • These aliphatic polyfunctional amines may be used alone or in combination of two or more.
  • the polyfunctional acid halide refers to an acid halide having at least two carbonyl halide groups in one molecule.
  • examples of the trifunctional acid halide include trimesic acid chloride, 1,3,5-cyclohexanetricarboxylic acid trichloride, 1,2,4-cyclobutanetricarboxylic acid trichloride, and the like.
  • bifunctional acid halide examples include aromatic bifunctional acid halides such as biphenyl dicarboxylic acid dichloride, azobenzene dicarboxylic acid dichloride, terephthalic acid chloride, isophthalic acid chloride, and naphthalene dicarboxylic acid chloride; adipoyl chloride, sebacoyl chloride, and the like.
  • aromatic bifunctional acid halides such as biphenyl dicarboxylic acid dichloride, azobenzene dicarboxylic acid dichloride, terephthalic acid chloride, isophthalic acid chloride, and naphthalene dicarboxylic acid chloride; adipoyl chloride, sebacoyl chloride, and the like.
  • Aliphatic bifunctional acid halides; cycloaliphatic difunctional acid halides such as cyclopentane dicarboxylic acid dichloride, cyclohexane dicarboxylic acid dichloride, and
  • the polyfunctional acid halide is preferably a polyfunctional acid chloride.
  • the polyfunctional acid chloride is more preferably a polyfunctional aromatic acid chloride having 2 to 4 carbonyl chloride groups in one molecule.
  • trimesic acid chloride hereinafter sometimes referred to as “TMC”.
  • TMC trimesic acid chloride
  • the polyamide constituting the separation functional layer is obtained by the reaction of the above-mentioned aliphatic polyfunctional amine and polyfunctional acid halide, and obtained by interfacial polycondensation with the aliphatic polyfunctional amine and polyfunctional acid halide.
  • the cross-linked polyamide is preferable from the viewpoint of ease of production.
  • the polyamide separation functional layer has an amide group derived from polymerization of an aliphatic polyfunctional amine and a polyfunctional acid halide, an amino group derived from an unreacted functional group, and a carboxy group.
  • the amide group ratio represented by the following formula has high scratch resistance when the amide group ratio is 0.80 or more.
  • the amide group ratio is more preferably 0.90 or more.
  • (Amide group ratio) (amide group molar ratio) / ⁇ (aliphatic polyfunctional amine molar ratio) + (polyfunctional acid halide molar ratio) ⁇
  • the molar ratio of the amide group, the molar ratio of the aliphatic polyfunctional amine, and the molar ratio of the polyfunctional acid halide in the formula can be determined by 13 C solid state NMR measurement of the separation functional layer. Specifically, after peeling the base material from the composite semipermeable membrane 5m 2 to obtain a polyamide separation functional layer and a porous support layer, the porous support layer is dissolved and removed to obtain a polyamide separation functional layer. The obtained polyamide separation functional layer is measured by DD / MAS- 13C solid-state NMR method, and each ratio is calculated by comparing the integrated value of the carbon peak of each functional group or the carbon peak to which each functional group is bonded. be able to.
  • the polyamide separation functional layer may be rubbed. As a result, it is known that the membrane performance, particularly the divalent ion removal rate, is lowered.
  • the separation functional layer has an amide group ratio of 0.80 or more, it is possible to reduce performance deterioration due to rubbing.
  • the amide group ratio is preferably 0.90 or more.
  • the present inventors have intensively studied. As a result, the hardness of the separation functional layer is correlated with the scratch resistance of the composite semipermeable membrane. We found that the performance is improved.
  • the average deformation amount at 90% of the maximum load when pushed at 5 nN is preferably 2.1 nm or less, and more preferably 1.5 nm or less. The amount of deformation when pushed in with a force of 5 nN can be measured, for example, with an atomic force microscope (AFM).
  • the inventors focused on the structure of the convex portion on the surface of the separation functional layer and conducted intensive studies. As a result, it was found that the number density of the convex portions on the surface of the separation functional layer correlates with the scratch resistance of the composite semipermeable membrane, and the higher the number density, the higher the scratch resistance. In order to reduce the performance degradation due to rubbing, when observing the surface of any 10 places with a length of 2 ⁇ m in the film surface direction of the composite semipermeable membrane, the average number density of convex portions on each surface is 11 / ⁇ m. The above is preferable.
  • the thickness of the polyamide separation functional layer is large, it is considered that the performance degradation due to abrasion can be reduced.
  • the smaller the thickness of the separation functional layer the better the water permeability.
  • the thickness of the separation functional layer is 10 nm or more and 50 nm or less, both high scratch resistance and water permeability can be achieved.
  • the thickness of the separation functional layer can be analyzed using an observation technique such as a transmission electron microscope, TEM tomography, or a focused ion beam / scanning electron microscope (FIB / SEM).
  • an observation technique such as a transmission electron microscope, TEM tomography, or a focused ion beam / scanning electron microscope (FIB / SEM).
  • FIB / SEM focused ion beam / scanning electron microscope
  • the composite nanofiltration membrane is treated with a water-soluble polymer to maintain the shape of the separation functional layer, and then stained with osmium tetroxide or the like for observation.
  • the thickness of a layer or film means an average value.
  • the average value represents an arithmetic average value.
  • the thickness of the layer or film is obtained by calculating the average value of the thicknesses of 20 points measured at intervals of 20 ⁇ m in the direction orthogonal to the thickness direction in the cross-sectional observation of the layer or film (the surface direction of the layer or film or the horizontal direction). It is done.
  • the support membrane includes a base material and a porous support layer provided on the base material, and has substantially no separation performance of ions or the like, and has a strength in the separation functional layer. Can be given.
  • the thickness of the support membrane affects the strength of the composite semipermeable membrane and the packing density when the composite semipermeable membrane is used as a membrane element.
  • the thickness of the support membrane is preferably in the range of 50 to 300 ⁇ m, more preferably in the range of 100 to 250 ⁇ m.
  • the porous support layer has substantially no separation performance for ions and the like, and is intended to give strength to the separation functional layer having substantially the separation performance. It is.
  • the size and distribution of the pores of the porous support layer are not particularly limited.For example, uniform and fine pores, or gradually having fine pores from the surface on the side where the separation functional layer is formed to the other surface, and A porous support layer having a fine pore size of 0.1 nm or more and 100 nm or less on the surface on the side where the separation functional layer is formed is preferred, but the material used and its shape are not particularly limited.
  • polysulfone, polyethersulfone, polyamide, polyester, cellulosic polymer, vinyl polymer, polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfone, or homopolymer or copolymer such as polyphenylene oxide, alone or in a blend Can be used.
  • cellulose acetate, cellulose nitrate and the like are used as the cellulose polymer, and polyethylene, polypropylene, polyvinyl chloride, polyacrylonitrile and the like can be used as the vinyl polymer.
  • a homopolymer such as polysulfone, polyamide, polyester, cellulose acetate, cellulose nitrate, polyvinyl chloride, polyacrylonitrile, polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfone, or a copolymer thereof is preferable.
  • polysulfone More preferred is cellulose acetate, polysulfone, polyphenylene sulfide sulfone, or polyphenylene sulfone.
  • polysulfone can generally be used because of its high chemical, mechanical and thermal stability and easy molding.
  • polysulfone composed of repeating units represented by the following chemical formula as the main component of the porous support layer because the pore diameter can be easily controlled and the dimensional stability is high.
  • the polysulfone used in the present invention preferably has a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) using N-methylpyrrolidone as a developing solvent and polystyrene as a standard substance. Those within the range of 200,000, more preferably 15,000 to 100,000.
  • the Mw is 10,000 or more, preferable mechanical strength and heat resistance can be obtained as the porous support layer. Moreover, when Mw is 200,000 or less, the viscosity of the solution falls within an appropriate range, and good moldability can be realized.
  • the porous support layer is prepared by, for example, casting an N, N-dimethylformamide (hereinafter also referred to as “DMF”) solution in which the above polysulfone is dissolved to a certain thickness on a substrate. Can be obtained by wet coagulation in water. Most of the surface of the support membrane obtained by this method can have fine pores having a diameter of 1 to 30 nm.
  • DMF N, N-dimethylformamide
  • the thickness of the porous support layer affects the strength of the resulting composite semipermeable membrane and the packing density when it is used as an element.
  • the thickness is preferably in the range of 10 to 200 ⁇ m, more preferably in the range of 20 to 150 ⁇ m.
  • the morphology of the porous support layer can be observed with a scanning electron microscope, a transmission electron microscope, or an atomic microscope.
  • a scanning electron microscope after peeling off the porous support layer from the substrate, it is cut by the freeze cleaving method to obtain a sample for cross-sectional observation.
  • the sample is thinly coated with platinum or platinum-palladium or ruthenium tetrachloride, preferably ruthenium tetrachloride, and observed with a high resolution field emission scanning electron microscope (UHR-FE-SEM) at an acceleration voltage of 3 to 15 kV.
  • UHR-FE-SEM high resolution field emission scanning electron microscope
  • Hitachi S-900 electron microscope can be used.
  • the surface of the porous support layer (that is, the surface facing the separation functional layer) has a granular structure, but the higher the particle density, the higher the number density of convex portions in the separation functional layer. This is considered to be due to the following reason.
  • the polyfunctional amine aqueous solution is in contact with the support membrane, and the polyfunctional amine aqueous solution is transferred from the inside of the porous support layer to the surface during polycondensation.
  • the surface of the porous support layer functions as a reaction field for polycondensation, and the polyfunctional amine aqueous solution is supplied from the inside of the porous support layer to the reaction field, whereby the convex portion of the separation functional layer grows.
  • a porous support layer having a high number density of grains on the surface is dense and has a small porosity and a small pore diameter.
  • the porosity of the porous support layer is high, the pore diameter is large, and the continuity is high, the monomer supply rate is increased, so that interfacial polymerization is promoted and the amide group ratio is increased.
  • the number density of the convex portions and the amide group ratio are determined by the polyfunctional amine aqueous solution holding capacity, the release rate and the supply amount of the porous support layer, and the number density of the convex portions can be controlled by the surface structure.
  • the number density of the convex portions is high, the physical external force applied to one convex portion is small, and thus the scratch resistance of the separation functional layer is high.
  • a pore having a pore size of 0.1 nm or more and 100 nm or less is preferable.
  • Substrate examples of the substrate constituting the support membrane include a polyester polymer, a polyamide polymer, a polyolefin polymer, or a mixture or copolymer thereof.
  • a polyester polymer is preferable because an excellent support film can be obtained due to mechanical strength, heat resistance, water resistance, and the like.
  • the polyester polymer used in the present invention is a polyester composed of an acid component and an alcohol component, and is preferably the main component of the substrate in the present invention.
  • the acid component examples include aromatic carboxylic acids such as terephthalic acid, isophthalic acid and phthalic acid; aliphatic dicarboxylic acids such as adipic acid and sebacic acid; and alicyclic dicarboxylic acids such as cyclohexanecarboxylic acid.
  • alcohol component ethylene glycol, diethylene glycol, polyethylene glycol, or the like can be used.
  • polyester polymer examples include polyethylene terephthalate resin, polybutylene terephthalate resin, polytrimethylene terephthalate resin, polyethylene naphthalate resin, polylactic acid resin, and polybutylene succinate resin.
  • polyester polymer examples include coalescence.
  • a polyethylene terephthalate homopolymer or a copolymer thereof is preferably used because it is particularly excellent in production cost.
  • the base material in the present invention is a cloth-like material made of the polymer or the like. It is preferable to use a fibrous base material for the fabric in terms of strength, unevenness forming ability, and fluid permeability.
  • both a long fiber nonwoven fabric and a short fiber nonwoven fabric can be used preferably.
  • the fibers in the surface layer on the side opposite to the porous support layer are preferably longitudinally oriented as compared with the fibers in the surface layer on the porous support layer side in terms of moldability and strength. The longitudinal alignment will be described later.
  • the fiber orientation degree in the surface layer of the long fiber nonwoven fabric or short fiber nonwoven fabric opposite to the porous support layer is preferably 0 ° to 25 °. Further, it is preferable that the difference in the degree of orientation between the fiber orientation degree on the surface layer opposite to the porous support layer and the fiber orientation degree on the surface layer on the porous support layer side is 10 ° to 90 °.
  • a heating process is included, but a phenomenon occurs in which the porous support layer or the separation functional layer contracts due to the heating. This is particularly noticeable in the width direction where no tension is applied in continuous film formation.
  • the “fiber orientation degree” is an index indicating the fiber orientation of the nonwoven fabric base material constituting the porous support layer.
  • a nonwoven fabric base material when the film forming direction for continuous film formation that is, the longitudinal direction of the nonwoven fabric base material is 0 °
  • the direction perpendicular to the film forming direction that is, the width direction of the nonwoven fabric base material is 90 °. This refers to the average angle of the constituent fibers. Accordingly, the closer to 0 ° the fiber orientation, the longer the orientation, and the closer to 90 °, the lateral orientation.
  • the fiber orientation degree is measured as follows. Ten small sample samples are randomly collected from the nonwoven fabric, and the surface of the sample is photographed at 100 to 1000 times with a scanning electron microscope. In the photographed image, 10 fibers are selected from each sample, and for a total of 100 fibers, the longitudinal direction (longitudinal direction, film forming direction) of the nonwoven fabric is 0 °, and the width direction (lateral direction) of the nonwoven fabric is 90 degrees. Measure the angle at °. In the average value of the measured angles, the value obtained by rounding off the first decimal place is the fiber orientation degree.
  • the air permeability of the substrate is preferably 2.0 cc / cm 2 / sec or more. When the air permeability is within this range, the water permeability of the composite semipermeable membrane is enhanced. This is a process of forming a porous support membrane. When a polymer is cast on a base material and immersed in a coagulation bath, the non-solvent replacement rate from the base material side becomes faster. This is presumably because the internal structure of the support layer changes and affects the amount of monomer retained and the diffusion rate in the subsequent step of forming the separation functional layer.
  • the air permeability can be measured by a Frazier type tester based on JIS L1096 (2010). For example, a base material is cut out to a size of 200 mm ⁇ 200 mm and used as a sample. This sample is attached to the Frazier type tester, and the suction fan and air hole are adjusted so that the inclined barometer has a pressure of 125 Pa. Based on the pressure indicated by the vertical barometer at this time and the type of air hole used, The amount of air passing through the material, that is, the air permeability can be calculated. As the Frazier type tester, KES-F8-AP1 manufactured by Kato Tech Co., Ltd. can be used.
  • the thickness of the substrate is preferably in the range of 10 to 200 ⁇ m from the viewpoint of mechanical strength and packing density, and more preferably in the range of 30 to 120 ⁇ m.
  • the support membrane used in the present invention can be selected from various commercially available materials such as “Millipore Filter VSWP” (trade name) manufactured by Millipore, and “Ultra Filter UK10” (trade name) manufactured by Toyo Roshi Kaisha, “Office of Saleen Water Research and Development Progress Report” No. 359 (1968).
  • the thickness of the base material and the thickness of the composite semipermeable membrane can be measured with a digital thickness gauge. Moreover, since the thickness of the separation functional layer is very thin compared to the porous support membrane, the thickness of the composite semipermeable membrane can be regarded as the thickness of the porous support membrane. Therefore, the thickness of the porous support layer can be easily calculated by measuring the thickness of the composite semipermeable membrane with a digital thickness gauge and subtracting the thickness of the substrate from the thickness of the composite semipermeable membrane. As the digital thickness gauge, PEACOCK manufactured by Ozaki Manufacturing Co., Ltd. can be used. When a digital thickness gauge is used, the average value is calculated by measuring the thickness at 20 locations.
  • the thickness may be measured with a scanning electron microscope. Thickness is calculated
  • the manufacturing method includes a support film forming step and a separation functional layer forming step.
  • the support film forming step includes a step of applying a polymer solution to a substrate and a step of immersing the substrate coated with the solution in a coagulation bath to coagulate the polymer. .
  • the polymer solution is prepared by dissolving the polymer that is a component of the porous support layer in a good solvent for the polymer.
  • the polysulfone concentration of the polymer solution is preferably 13% by weight or more and 17% by weight or less. Since the polysulfone concentration of the polymer solution is 13% by weight or more and 17% by weight or less, the communication holes are formed to be relatively small, so that a desired pore diameter can be easily obtained.
  • the polysulfone concentration of the polymer solution is less than 13% by weight, the surface pores tend to be large, and when the separation functional layer is formed, the number of growth points of the protrusions decreases, and as a result, the number density of the protrusions is Lower. Further, when the polysulfone concentration in the polymer solution exceeds 17% by weight, the surface pores tend to be small, and when the separation functional layer is formed, the monomer supply rate is low, resulting in a low amide group ratio. Become.
  • the temperature of the polymer solution during application of the polymer solution is preferably in the range of 10 ° C. to 60 ° C. when polysulfone is used as the polymer. If the temperature of the polymer solution is within this range, the polymer does not precipitate, and the polymer solution is sufficiently impregnated between the fibers of the base material and then solidified. As a result, the porous support layer is firmly bonded to the substrate by the anchor effect, and a good support film can be obtained.
  • the preferred temperature range of the polymer solution can be adjusted as appropriate depending on the type of polymer used, the desired solution viscosity, and the like.
  • the time from application of the polymer solution on the substrate to immersion in the coagulation bath is preferably in the range of 0.1 to 5 seconds. If the time until dipping in the coagulation bath is within this range, the organic solvent solution containing the polymer is sufficiently impregnated between the fibers of the base material and then solidified.
  • the preferable range of time until it immerses in a coagulation bath can be suitably adjusted with the kind of polymer solution to be used, desired solution viscosity, etc.
  • the coagulation bath water is usually used, but any solid can be used as long as it does not dissolve the polymer that is a component of the porous support layer.
  • the membrane form of the support membrane obtained by the composition of the coagulation bath changes, and the resulting composite semipermeable membrane also changes.
  • the temperature of the coagulation bath is preferably 5 ° C to 100 ° C. More preferably, it is 10 ° C to 40 ° C. If the temperature of the coagulation bath is lower than the upper limit, vibration of the coagulation bath surface due to thermal motion can be suppressed, and the smoothness of the film surface after film formation can be maintained. Further, if the temperature is equal to or higher than the lower limit, the solidification rate can be maintained, so that the film forming property can be improved.
  • the support membrane thus obtained is washed with hot water in order to remove the solvent remaining in the membrane.
  • the temperature of the hot water at this time is preferably 40 ° C. to 100 ° C., more preferably 60 ° C. to 95 ° C.
  • the washing temperature is lower than the upper limit, the shrinkage of the support membrane does not become too large, and the water permeability can be prevented from being lowered.
  • the cleaning temperature is equal to or higher than the lower limit, the cleaning effect is sufficient.
  • the concentration of the aliphatic polyfunctional amine in the aliphatic polyfunctional amine aqueous solution is preferably 1.0% by weight or more, and preferably 8.0% by weight or less.
  • concentration of the aliphatic polyfunctional amine is 1.0% by weight or more, a uniform separation function layer is formed, sufficient divalent ion removal performance can be obtained, and high scratch resistance can be obtained.
  • separation functional layer will not become thick too much, and sufficient water permeability will be obtained.
  • the aqueous solution containing the aliphatic polyfunctional amine is preferably pH 10 or more and pH 13 or less, more preferably pH 11 or more and pH 12 or less. If the pH of the aqueous solution containing the aliphatic polyfunctional amine is within this range, the hydrogen halide generated by the interfacial polycondensation reaction can be removed, and the decrease in the reactivity of the aliphatic polyfunctional amine can be suppressed. Hydrolysis of the polyfunctional acid halide by oxide ions can be suppressed, the amide group ratio is 0.80 or more, and the separation functional layer thickness is 10 nm or more.
  • alkali compound to adjust pH examples include sodium hydroxide, trisodium phosphate, triethylamine and the like.
  • a surfactant may be included in the aqueous solution containing the aliphatic polyfunctional amine.
  • examples thereof include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium dodecyldiphenyl ether disulfonate, styrene bis (sodium naphthalenesulfonate), sodium polyoxyethylene alkyl ether sulfate, and the like.
  • the aqueous solution containing the aliphatic polyfunctional amine may contain alcohol.
  • an alcohol such as ethanol, 1-propanol, 2-propanol, or butanol, the effect of disturbing the interfacial polycondensation field and increasing the amount of functional groups, particularly the amount of amino groups, in the polyamide can be obtained.
  • a solubility parameter (SP value) that is immiscible with water, does not destroy the support membrane, and does not inhibit the formation reaction of the crosslinked polyamide.
  • SP value a solubility parameter that is immiscible with water, does not destroy the support membrane, and does not inhibit the formation reaction of the crosslinked polyamide.
  • SP value is 15.2 (MPa) 1/2 or more and logP is 3.2 or more, distribution and diffusion of piperazine during interfacial polycondensation are optimized, and the amount of functional groups may be increased. it can.
  • octane nonane, decane, undecane, dodecane, tridecane, tetradecane, heptadecane, hexadecane, etc.
  • simple substances such as cyclooctane, ethylcyclohexane, 1-octene, 1-decene or mixtures thereof are preferably used.
  • the concentration of the polyfunctional acid halide in the organic solvent solution immiscible with water is preferably in the range of 0.01 wt% to 10 wt%, and preferably 0.02 wt% to 2.0 wt%. More preferably within the range.
  • concentration is 0.01% by weight or more, a sufficient reaction rate can be obtained, and when it is 10% by weight or less, the occurrence of side reactions can be suppressed.
  • an aqueous solution containing an aliphatic polyfunctional amine and an organic solvent solution containing a polyfunctional acid halide compounds such as an acylation catalyst, a polar solvent, an acid scavenger, and an antioxidant are added as necessary. It may be included.
  • the support membrane surface is first coated with an aqueous solution containing an aliphatic polyfunctional amine.
  • an aqueous solution containing an aliphatic polyfunctional amine As a method of coating the surface of the support membrane with an aqueous solution containing an aliphatic polyfunctional amine, it is sufficient that the surface of the support membrane is uniformly and continuously coated with this aqueous solution, and a known coating means, for example, an aqueous solution is supported. What is necessary is just to perform by the method of coating on the surface of a membrane, the method of immersing a support membrane in aqueous solution, etc.
  • the contact time between the support membrane and the aqueous solution containing the aliphatic polyfunctional amine is preferably in the range of 5 seconds to 10 minutes, and more preferably in the range of 10 seconds to 2 minutes.
  • a liquid draining step there are, for example, a method of holding the film surface in a vertical direction and letting it flow down naturally, a method of removing it by blowing air, and the like.
  • the membrane surface may be dried to remove all or part of the water in the aqueous solution.
  • an organic solvent solution containing the above-mentioned polyfunctional acid halide is applied to a support film coated with an aqueous solution containing an aliphatic polyfunctional amine, and a separation functional layer of crosslinked polyamide is formed by interfacial polycondensation.
  • the time for performing the interfacial polycondensation is preferably from 0.1 second to 3 minutes, and more preferably from 0.1 second to 1 minute.
  • the interfacial polymerization is preferably performed under a temperature condition of 30 ° C. or higher, and more preferably performed under a temperature condition of 40 ° C. or higher.
  • the interfacial polymerization is preferably performed under a temperature condition of 80 ° C. or lower.
  • Interfacial polymerization is performed at 30 ° C. or higher, so that in the interfacial polymerization reaction, a decrease in the mobility of monomers and oligomers due to an increase in the bulkiness of the polyamide can be suppressed, and the amide group ratio becomes 0.80 or higher.
  • the thickness of the separation functional layer is 10 nm or more.
  • the separation functional layer has a thickness of 50 nm or less to ensure practical water permeability. can do.
  • the temperature of the organic solvent solution when applied to the support film is preferably in the above range, but after applying to the support film, the temperature of the organic solvent solution is set within this range by heating the organic solvent solution. You may adjust.
  • the heating method is not particularly limited, and various methods such as a method of blowing hot air, a method of irradiating infrared rays, and heating by electromagnetic waves such as microwaves can be used.
  • the organic solvent can be removed by, for example, a method in which the membrane is vertically held and the excess organic solvent is allowed to flow down and removed, a method in which the organic solvent is dried by blowing air with a blower, a mixed fluid of water and air (for example, a method of removing excess organic solvent with 2 fluids) can be used.
  • a mixed fluid of water and air is preferable.
  • water is included in the separation functional layer, so that it swells and water permeability increases.
  • the vertical gripping time is preferably between 1 minute and 5 minutes, more preferably between 1 minute and 3 minutes.
  • the holding time is 1 minute or longer, it is easy to obtain a separation functional layer having the desired function, and when it is 3 minutes or shorter, generation of defects due to over-drying of the organic solvent can be suppressed, thereby suppressing deterioration in performance. Can do.
  • the composite semipermeable membrane obtained by the above-described method is further added with a process of washing with hot water for 1 minute to 60 minutes within the range of 25 ° C to 90 ° C, so that the solute blocking performance of the composite semipermeable membrane is added. And water permeability can be further improved.
  • the composite semipermeable membrane of the present invention can be suitably used as a nanofiltration membrane for removing divalent ions.
  • This composite semipermeable membrane is applicable to salt removal or mineral adjustment from canned water or seawater, and salt removal or mineral adjustment in the food field, for example.
  • the composite semipermeable membrane of the present invention is suitably used for membrane separation treatment before distillation on raw water (for example, seawater, surface water, etc.) in a method for obtaining fresh water by a distillation method.
  • a distillation method By this membrane separation treatment, it is possible to obtain permeated water that is reduced to such an extent that the scale component does not become a practical problem.
  • Fresh water is obtained by processing the permeated water thus obtained by a distillation method.
  • precipitation of scales such as CaCO 3 , Mg (OH) 2 , and CaSO 4 can be effectively suppressed in the distillation step.
  • Examples of the distillation method in the present invention include a multistage distillation method, a multiple effect method, an evaporation compression method, and the like, and the multistage distillation method is particularly preferable.
  • the multistage distillation method is a preferable method because the thermal energy required to obtain the same amount of fresh water can be greatly reduced as compared with a method in which the entire amount is evaporated in one stage.
  • the composite semipermeable membrane of the present invention has a cylindrical shape in which a large number of holes are perforated together with a raw water channel material such as a plastic net, a permeate channel material such as tricot, and a film for enhancing pressure resistance as required. It is wound around a water collecting pipe and is preferably used as a spiral composite semipermeable membrane element. Furthermore, a composite semipermeable membrane module in which these elements are connected in series or in parallel and accommodated in a pressure vessel can be obtained.
  • the above-described composite semipermeable membrane, its elements, and modules can be combined with a pump for supplying raw water to them, a device for pretreating the raw water, and the like to constitute a fluid separation device.
  • a separation device By using this separation device, raw water can be separated into permeated water such as drinking water and concentrated water that has not permeated through the membrane, and water suitable for the purpose can be obtained.
  • the base material was physically peeled from the composite semipermeable membrane 5 m 2 to recover the porous support layer and the separation functional layer.
  • the recovered porous support layer and separation functional layer were washed with warm water at 95 ° C. for 2 hours. After drying by standing at 25 ° C. for 24 hours, it was added little by little in a beaker containing dichloromethane, and the polymer constituting the porous support layer was dissolved. Insoluble matter in the beaker was collected with filter paper. This insoluble matter was placed in a beaker containing dichloromethane and stirred to collect the insoluble matter in the beaker. This operation was repeated until the polymer forming the porous support layer in the dichloromethane solution could not be detected. The collected separation functional layer was dried with a vacuum dryer to remove the remaining dichloromethane.
  • the obtained separation functional layer weight was made into a powdery sample by freeze pulverization, sealed in a sample tube used for solid NMR measurement, and subjected to 13 C solid NMR measurement by CP / MAS method and DD / MAS method. .
  • 13 C solid state NMR measurement for example, CMX-300 manufactured by Chemicals can be used. An example of measurement conditions is shown below.
  • ⁇ Hardness of separation functional layer> The amount of deformation of the separation functional layer in Examples and Examples was measured as follows.
  • the composite semipermeable membrane was cut into a 1 cm square, and the membrane surface was observed with a Dimension FastScan manufactured by Bruker AXS. From the obtained image, ten force curves of the convex portions were extracted, and the deformation amount was analyzed. This operation was performed for three visual fields, and a total of 30 deformation amounts were calculated. Specific measurement conditions are as follows.
  • ⁇ Density density of separation functional layer> The membrane surface was observed by the same method as the measurement of the deformation amount of the separation functional layer, and the number of convex portions density was measured.
  • the composite semipermeable membrane was cut into a 1 cm square, and the membrane surface was observed with a Dimension FastScan manufactured by Bruker AXS. About the obtained image, the number of the convex parts in the distance of the width
  • ⁇ Thickness of separation functional layer> The composite semipermeable membrane was embedded with PVA and then stained with osmium tetroxide to obtain a measurement sample. The obtained sample was photographed using TEM tomography, and the obtained 3D image was analyzed by analysis software. For TEM tomography analysis, JEOL field emission analytical electron microscope JEM2100F was used. Using the acquired image at a magnification of 300,000 times, the thickness of the separation functional layer is measured, and an average value of a total of 50 points is obtained.
  • MgSO 4 removal rate ⁇ 1- / ( MgSO 4 concentration in the feed solution) (MgSO 4 concentration in the permeate) ⁇ ⁇ 100
  • FIG. 1 shows a composite semipermeable membrane element of the present invention.
  • a membrane unit 7 including a composite semipermeable membrane 4, a permeate channel material 5, and a stock solution channel material 6 is spirally wound around a water collection pipe 3 having a water collection hole 2.
  • the exterior body 8 is formed outside the membrane unit 7 to form a fluid separation element 9.
  • a telescope prevention plate 10 for preventing the fluid separation element 9 from being deformed into a telescope shape is attached to the end face of the fluid separation element 9, thereby forming the composite semipermeable membrane element 1.
  • Example 1 ⁇ Production of composite semipermeable membrane> A 15% by weight dimethylformamide (DMF) solution of polysulfone was cast at a room temperature (25 ° C.) at a coating thickness of 180 ⁇ m on a non-woven fabric (air permeability 1.0 cc / cm 2 / sec) made of polyester fiber manufactured by a papermaking method. Thereafter, the substrate was immediately immersed in pure water for 5 minutes to form a porous support layer on the substrate, thereby preparing a support film.
  • DMF dimethylformamide
  • the membrane performance obtained by evaluating the composite semipermeable membrane thus obtained was a value shown in Table 2.
  • Example 2 Comparative Examples 1 to 5
  • Example 2 a composite semipermeable membrane was prepared in the same manner as in Example 1 except that the piperazine concentration, trimesic acid chloride concentration, sodium dodecyl diphenyl ether disulfonate concentration, and pH of the aqueous solution containing piperazine were changed to the values shown in Table 1. did.
  • Table 2 shows the membrane performance of the obtained composite semipermeable membrane.
  • Example 7 to 8 Composite semipermeable membranes in Examples 7 to 8 were produced in the same manner as in Example 1 except that the alkali compounds shown in Table 1 were used in Example 1. Table 2 shows the membrane performance of the obtained composite semipermeable membrane.
  • Example 9 A composite semipermeable membrane in Example 9 was produced in the same manner as in Example 1 except that 1% by weight of isopropyl alcohol was dissolved in an aqueous solution containing piperazine in Example 1. Table 2 shows the membrane performance of the obtained composite semipermeable membrane.
  • Example 10 In Example 1, a composite semipermeable membrane in Example 10 was produced in the same manner as in Example 1 except that Isoper M (manufactured by ExxonMobil) was used as the organic solvent for dissolving trimesic acid chloride. Table 2 shows the membrane performance of the obtained composite semipermeable membrane.
  • Example 11 to 13 Comparative Example 6
  • the pH of the aqueous solution containing piperazine was adjusted to 12.2
  • the temperature of n-decane containing trimesic acid chloride and the temperature of standing for 1 minute were changed to the values shown in Table 1.
  • Table 2 shows the membrane performance of the obtained composite semipermeable membrane.
  • Example 14 Example 1 was carried out in the same manner as in Example 1 except that the piperazine concentration, the pH of the aqueous solution containing piperazine, the temperature of n-decane containing trimesic acid chloride, and the temperature of standing for 1 minute were set to the values shown in Table 1. A composite semipermeable membrane in Example 14 was produced. Table 2 shows the membrane performance of the obtained composite semipermeable membrane.
  • Example 15 In Example 1, the composite semipermeable membrane in Example 15 was prepared in the same manner as in Example 1 except that the temperature of n-decane containing trimesic acid chloride was 40 ° C. and the temperature of standing for 1 minute was 40 ° C. Produced. Table 2 shows the membrane performance of the obtained composite semipermeable membrane.
  • Example 16 to 19 Comparative Examples 7 to 8
  • Example 1 composite semipermeable membranes in Example Examples 16 to 19 and Comparative Examples 7 to 8 were produced in the same manner as Example 1 except that the polysulfone concentration was changed to the value shown in Table 1.
  • Table 2 shows the membrane performance of the obtained composite semipermeable membrane.
  • Example 20 In Example 1, the same procedure as in Example 1 was carried out except that the polysulfone concentration was 16% by weight, the temperature of n-decane containing trimesic acid chloride was 40 ° C., and the temperature of standing for 1 minute was 40 ° C. A composite semipermeable membrane at 20 was prepared. Table 2 shows the membrane performance of the obtained composite semipermeable membrane.
  • the composite semipermeable membrane having a separation functional layer having an amide group ratio of 0.80 or more and having a separation functional layer thickness of 10 nm to 50 nm has water permeability performance suitable for practical use, High scratch resistance.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Polyamides (AREA)

Abstract

L'objectif de la présente invention est de fournir une membrane semi-perméable composite ayant une résistance élevée à la rayure. Une membrane semi-perméable composite selon la présente invention est pourvue : d'un film de support qui comprend une base et une couche de support poreuse disposée sur la base ; et une couche fonctionnelle de séparation en polyamide qui est formée sur la couche de support poreuse. La couche fonctionnelle de séparation en polyamide est une couche constituée d'un polyamide qui est obtenu à partir d'une amine polyfonctionnelle aliphatique et d'un halogénure d'acide polyfonctionnel. Le rapport des groupes amide du polyamide aliphatique dans la couche fonctionnelle de séparation en polyamide, ledit rapport des groupes amide étant représenté par la formule ci-dessous, est d'au moins 0,80, et l'épaisseur de la couche fonctionnelle de séparation en polyamide est de 10 nm à 50 nm (inclus). (Rapport des groupes amide) = (rapport des quantités molaires de groupes amide)/{(rapport des quantités molaires d'amine polyfonctionnelle aliphatique) + (rapport des quantités molaires d'halogénure d'acide polyfonctionnel)}
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2018198679A1 (ja) * 2017-04-28 2020-02-27 東レ株式会社 複合半透膜及びその製造方法
WO2021085600A1 (fr) * 2019-10-31 2021-05-06 東レ株式会社 Membrane semi-perméable composite et son procédé de fabrication
US20220298121A1 (en) * 2019-05-24 2022-09-22 Soprema Amine terminated prepolymer and composition comprising the same

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JP2000033243A (ja) * 1998-05-11 2000-02-02 Toray Ind Inc 複合半透膜
JP2000202257A (ja) * 1999-01-14 2000-07-25 Toray Ind Inc 複合半透膜およびその製造方法
WO2014003141A1 (fr) * 2012-06-27 2014-01-03 東レ株式会社 Membrane composite semi-perméable
WO2014104241A1 (fr) * 2012-12-27 2014-07-03 東レ株式会社 Membrane semi-perméable composite
WO2014133132A1 (fr) * 2013-02-28 2014-09-04 東レ株式会社 Membrane composite semi-perméable
WO2014133133A1 (fr) * 2013-02-28 2014-09-04 東レ株式会社 Membrane composite semi-perméable

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JP2000033243A (ja) * 1998-05-11 2000-02-02 Toray Ind Inc 複合半透膜
JP2000202257A (ja) * 1999-01-14 2000-07-25 Toray Ind Inc 複合半透膜およびその製造方法
WO2014003141A1 (fr) * 2012-06-27 2014-01-03 東レ株式会社 Membrane composite semi-perméable
WO2014104241A1 (fr) * 2012-12-27 2014-07-03 東レ株式会社 Membrane semi-perméable composite
WO2014133132A1 (fr) * 2013-02-28 2014-09-04 東レ株式会社 Membrane composite semi-perméable
WO2014133133A1 (fr) * 2013-02-28 2014-09-04 東レ株式会社 Membrane composite semi-perméable

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2018198679A1 (ja) * 2017-04-28 2020-02-27 東レ株式会社 複合半透膜及びその製造方法
JP7010216B2 (ja) 2017-04-28 2022-01-26 東レ株式会社 複合半透膜及びその製造方法
US20220298121A1 (en) * 2019-05-24 2022-09-22 Soprema Amine terminated prepolymer and composition comprising the same
WO2021085600A1 (fr) * 2019-10-31 2021-05-06 東レ株式会社 Membrane semi-perméable composite et son procédé de fabrication

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