JP2022084357A - Composite semi-permeable membrane having graphene oxide layer - Google Patents

Abstract

To provide a new semi-permeable membrane which is useful for treatment (treatment such as separation, purification and concentration) of both liquids of a water-based liquid and an organic liquid.SOLUTION: A composite semi-permeable membrane has a graphene oxide layer on a porous base material membrane containing a polyketone resin. An amine compound is particularly preferably contained in the graphene oxide layer.SELECTED DRAWING: None

Description

Patent Law Article 30, Paragraph 2 Application Applicable Website Address http: // www 3. scej. org / meeting / stu22w / index. html http: // www3. scej. org / meeting / stu22w / abst / J11. pdf Publication date: February 17, 2nd year of Reiwa [Publications, etc.] Website address https://maku-jp. sakura. ne. jp / nenkai / 42 / https: // maku-jp. sakura. ne. jp / nenkai / 42 / 42_all. pdf Publication date: May 20, 2nd year of Reiwa

The present invention relates to a composite semipermeable membrane having a graphene oxide layer.

Reverse osmosis membranes (RO membranes) and nanofilter membranes (NF membranes) are separation membranes that have a molecular sieving function (semipermeable membrane function) in the low molecular weight region, such as desalination of seawater, purification of wastewater, and low molecular weight valuable resources. It is widely used for water-based liquid treatment such as purification and concentration. These RO membranes and NF membranes have their origins in the asymmetric membranes made of cellulose acetate (so-called Loeb membranes) invented in the 1960s. Since then, many improvements have been made, and nowadays, a porous film made of a high-strength resin such as polysulfone (a film having a pore size in the ultrapermeable filtration region) is used as a base film, and the surface thereof is densely formed by an interfacial polymerization method. A composite semipermeable membrane having a solid polyamide layer (having a molecular sieve function in a low molecular weight region) is the mainstream.

The good point of membrane separation is that substances can be separated without undergoing a phase change (gas ⇔ liquid ⇔ solid) while the liquid remains a liquid and the gas remains a gas. For this reason, membrane separation is a separation technology with less energy loss than existing separation technologies (distillation technology, recrystallization technology, etc.) that involve phase changes, and is an important technology for the sustainable development of the earth. From these points of view, technologies such as RO membranes and NF membranes that have been successful in water systems (for example, the distillation method was the mainstream for seawater desalination before, but now the RO membrane method has changed to the mainstream, and energy consumption has been reduced. There is a movement to apply (contribution) to organic liquid systems (Non-Patent Document 1, Non-Patent Document 2).

However, RO membranes and NF membranes used in water systems are strong in organic liquid systems (for example, the polysulfone porous membrane that is the base film dissolves in organic liquids) and separation performance (for example, in organic liquids). It is difficult to apply to organic liquid systems due to swelling and interaction with organic liquids. If there is a semipermeable membrane that can be applied to both water-based and organic liquid-based systems, it will be useful for expanding the scope of application of the membrane (expanding separation technology with less energy loss).

The progress in membrane material technology is remarkable, and membranes made of polyketone material having excellent organic liquid resistance have been reported (Patent Documents 1 to 3). In addition, as a new separation functional material (molecular sieve functional material), research on a graphene oxide material that can be expected to have organic liquid resistance has also been conducted (Non-Patent Document 3).

Japanese Unexamined Patent Publication No. 2017-144390 Japanese Unexamined Patent Publication No. 2002-348401 Japanese Unexamined Patent Publication No. 2-4431

D.S.Sholl and R.P.Lively, Nature, 532 (2016) 435-438 A.G.Livingston et al., Chemical Reviews, 114 (2014) 10735-10806 G. Liu, W. Jin and N. Xu, Chemical Society Reviews, 44 (2015) 5016-5030

An object of the present invention is to provide a new composite semipermeable membrane useful for both water-based liquid and organic-based liquid treatment (treatment such as separation, purification, and concentration).

As a result of diligent research and experiments to solve the above-mentioned problems, the inventors of the present application have found that the above-mentioned problems can be solved by the following configurations, and have completed the present invention. That is, the present invention is as follows.

<< Aspect 1 >> A composite semipermeable membrane having a graphene oxide layer on a porous substrate membrane containing a polyketone resin.
<< Aspect 2 >> The composite semipermeable membrane according to Aspect 1, wherein the graphene oxide layer contains an amine compound.

According to the present invention, a composite semipermeable membrane useful for both water-based and organic liquid-based treatments can be obtained.

It is an electron micrograph of the membrane cross section (near the graphene oxide layer) of the composite semipermeable membrane according to the present invention produced in Example 2. The porous base film containing the polyketone resin prepared in Example 5, the film prepared in Example 5 in which the graphene oxide layer is laminated on the porous base film, and the graphene oxide layer prepared in Reference Example 1. Is the measurement result of the infrared absorption method (FT-IR) of the three films of the film laminated on the porous substrate film. For the film in which the graphene oxide layer was laminated on the porous substrate film, FT-IR was measured on the graphene oxide laminated side.

Hereinafter, an exemplary embodiment for carrying out the present invention (hereinafter, also referred to as the present embodiment) will be described in detail. The present invention is not limited to the embodiments described below, and can be variously modified and used within the scope of the gist thereof.

The composite semipermeable membrane in the present embodiment generally has a porous substrate membrane made of a polyketone resin and a graphene oxide layer.

<Graphene oxide>
Graphene oxide is a hydroxyl group formed by oxidizing a part of the carbon of graphene (a two-dimensional (flat) sheet in which the sp ² -conjugated structure of a carbon six-membered ring is developed in a planar shape), which is a component of graphite. A two-dimensional (flat plate) sheet on which functional groups such as an epoxy group and a carboxyl group are fixed. Since it has a polar functional group (hydroxyl group, carboxyl group, etc.), it has the property of being flaky and easily dispersed in a polar solvent such as water.

Utilizing this property, flakes of graphene oxide (for example, a thickness of about 1 nm and a length of about 1 to several μm) can be densely and thinly laminated (a layer in which flat plates are stacked) on a substrate. When a liquid-permeable porous structural membrane is used as the base material, a liquid in which graphene oxide flakes are dispersed in a polar solvent is filtered onto the porous structural membrane to form a porous structural membrane (surface). Graphene oxide can be densely and thinly laminated.

The gaps between the laminated graphene oxide flakes (small gaps between the flat plates with the graphene oxide flakes existing above and below, and the minute gaps between the flanks with the horizontally adjacent graphene oxide flakes) are in the liquid. It may have a function as a molecular sieve capable of performing solute separation (separation by physical size separation and / or chemical interaction (electrostatic force, hydrogen bond, hydrophobic interaction, etc.)). Graphene oxide flakes can be prepared, for example, by the Improved Hammer's method (see D.C. Marcano et al., ACS Nano., 4 (2010) 4806-4814).

<Polyketone resin>
The polyketone resin is a copolymer of carbon monoxide and an olefin. For example, it can be obtained by copolymerizing carbon monoxide and an olefin using palladium, nickel or the like as a catalyst. Examples of the olefin include chain olefins such as ethylene, propylene, butene, hexene, octene and decene, alkenyl aromatic compounds such as styrene and α-methylstyrene, cyclopentene, norbornene, 5-methylnorbornene, tetracyclododecene and tricyclo. Examples thereof include cyclic olefins such as decene, pentacyclopentadecene and pentacyclohexadecene, alkene halides such as vinyl chloride and vinyl fluoride, acrylic acid esters such as ethyl acrylate and methyl methacrylate, and vinyl acetate. In a preferred embodiment, the polyketone resin has a repeating unit represented by the following formula (1).

-RC (= O)-(1)
(In the formula, R is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.)

Examples of the substituent contained in R in the above formula (1) include a halogen atom, a hydroxyl group, an ether group, a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, and a sulfonic acid group. Examples thereof include a sulfonic acid ester group, a carboxylic acid group, a carboxylic acid ester group, a phosphoric acid group, a phosphoric acid ester group, a thiol group, a sulfide group, an alkoxysilyl group, and a silanol group.

The carbon number of R in the above formula (1) is preferably 2 or more and 8 or less, more preferably 2 or more and 3 or less, and 2 is most preferable.

In particular, it is preferable that the polyketone resin contains a large number of repeating units of 1-oxotrimethylene represented by the following formula (2) from the viewpoint of ensuring the mechanical strength of the polyketone porous base film. Specifically, the ratio of the repeating unit of 1-oxotrimethylene to all the repeating units of the polyketone resin is preferably 70 mol% or more, more preferably 90 mol% or more, and 95 mol% or more. It is more preferably present, and may be 100 mol%.

-CH ₂ -CH ₂ -C (= O)-(2)

The molecular weight of the polyketone resin is not particularly limited, but is preferably 0.5 dL / g or more and 5 dL / g or less in the ultimate viscosity from the viewpoint of ease of molding into a porous membrane and mechanical strength. The ultimate viscosity of the polyketone resin can be measured, for example, by the method described in Japanese Patent No. 6210925.

<Polish substrate film>
The porous substrate membrane is a membrane on which a dense thin film layer having a molecular sieving function (in this embodiment, a graphene oxide layer) is placed, and is an important function that supports the mechanical strength of the composite semipermeable membrane. have. On the other hand, since it is preferable to reduce the permeation resistance of the liquid, a porous structural membrane is used.

Since a dense thin film layer having a molecular sieving function is placed on the surface of the porous substrate film without defects, the pore size of the portion in contact with the dense thin film layer having a molecular sieving function (the surface portion for the porous substrate film) is set. It is preferably small to some extent, that is, in the range of several nanometers to several hundreds of nanometers. Since it is preferable to reduce the permeation resistance of the liquid as a whole of the porous substrate membrane, the portion not in contact with the dense thin film layer having the molecular sieving function (most of the cross-sectional portion for the porous substrate membrane). Pore diameters larger than those ranging from a few nanometers to a few hundred nanometers are also acceptable. The macroscopic structure of the cross section of the porous substrate membrane is acceptable, whether it is a sponge-like structure or a structure containing voids. A porous substrate membrane having such a structure corresponds to a category of porous membranes known as ultrafiltration membranes and microfiltration membranes. The pore size of each portion of the porous substrate film can be confirmed, for example, by observing with an electron microscope.

The porosity of the porous substrate membrane is not particularly limited, but is preferably 50% to 95%, more preferably 60% to 90%, from the viewpoint of reducing the permeation resistance of the liquid and ensuring the mechanical strength. , 70% to 85% is more preferable. The porosity of the porous substrate film is calculated by the following mathematical formula (1).
Porosity (%) = (1-G ・ ρ ^-1・ V ^-1 ) × 100 (1)
(In the formula (1), G is the mass (g) of the support layer, ρ is the mass average density of the support layer (g / cm ³ ), and V is the volume of the support layer (cm ³ ).)

As the shape of the porous substrate membrane, an existing known ultrafiltration membrane or microfiltration membrane such as a flat membrane or a hollow fiber membrane is used. In the case of a flat film, as is known from existing RO films, it is also possible to use a non-woven fabric such as polyester as a base of the flat film-like porous substrate film.

The thickness of the porous substrate membrane can be measured, for example, by observing the cross section of the composite semipermeable membrane with an optical microscope or an electron microscope. The thickness of the porous substrate membrane is preferably thick from the viewpoint of ensuring the mechanical strength (compressive strength, etc.) that supports the molecular sieve layer, while increasing the liquid permeability (does not unnecessarily increase the permeation resistance). It is preferable that it is thin. Specifically, it is preferably 30 μm or more and less than 900 μm, more preferably 50 μm or more and 500 μm or less, and further preferably 100 μm or more and 250 μm or less. When the porous base film becomes thinner, the membrane volume becomes smaller, which makes it possible to reduce the size of the membrane operating device.

The porous base film made of a polyketone resin can be produced by a known method, and can be produced by referring to, for example, the method disclosed in Patent Document 2. That is, a method in which a polyketone resin is dissolved in a solvent (for example, an aqueous solution of resorcinol) to prepare a solution, and this solution is impregnated in a non-solvent (for example, an aqueous solution of methanol) of the polyketone resin and coagulated to obtain a porous substrate film. be.

The porous base film made of a polyketone resin may be appropriately modified. For example, introduction of various functional groups using a silane coupling agent, introduction of a carboxyl group (method described in C. Liu et al., J. Colloid interface Sci., 544 (2019) 230-240) and the like. By introducing an amino group into the porous base film with a silane coupling agent or the like, the porous base film and the laminated graphene oxide layer and the porous base film are formed by the interaction of the carboxyl groups in the graphene oxide. It can be expected to have effects such as strengthening the fixation between and. Further, by introducing a carboxyl group into the porous base film, graphene oxide laminated by the interaction between the porous base film and graphene oxide, which is also considered to have a carboxyl group, via, for example, an amine compound. Effects such as strengthening the fixation between the layer and the porous base film can be expected.

The silane coupling agent used for modifying the porous substrate film is not limited to the following, and is, for example, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-amino). Ethyl) Aminopropyltriethoxyxylan, 3- (6-aminohexyl) aminopropyltriethoxysilane, 3- (N, N-dimethylamino) propyltriethoxysilane, N-phenylaminomethyltriethoxysilane, N-phenyl- Examples thereof include aminosilanes such as 3-aminopropyltriethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, and N-cyclohexylaminomethyltriethoxysilane, and 3-aminopropyltriethoxysilane is preferable. Aminosilanes are bonded to the carbonyl group on the surface of the porous substrate film containing the polyketone resin by a hydrogen bond or the like (hydrogen bond between the amino group of the aminosilanes and the carbonyl group of the polyketone, etc.), and further an ethoxy group. After the methoxy group is converted to a hydroxyl group by hydrolysis, it reacts with the hydroxyl group on the surface of graphene oxide (dehydration condensation, etc.) or hydrogen-bonds with the hydroxyl group, carboxyl group, carbonyl group, etc. on the surface of graphene oxide, and the stability of the graphene oxide layer. It is presumed that it contributes to the enhancement of.

The polyvalent carboxylic acid or its acid anhydride or acid chloride used for introducing a carboxyl group into the porous substrate film may be a known and commonly used one, and is not particularly limited, but for example, succinic acid and anhydrous succinic acid. Acid, adipic acid, sebacic acid, terephthalic acid, phthalic anhydride, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, tetracarboxylic acid of tetrahydrofuran, tetracarboxylic acid anhydride of tetrahydrofuran, dichloride succinate , Adipic acid dichloride, sebacic acid dichloride, terephthalic acid dichloride, 2-chloro-terephthalic acid dichloride, isophthalic acid dichloride, 2,6-naphthalenedicarboxylic acid dichloride, 4,4'-biphenyldicarbonyl chloride, 1,4-cyclohexanedicarboxylic Examples thereof include acid dichloride, 1,3-cyclohexanedicarboxylic acid dichloride, 1,1'-bicyclohexane-4,4'-dicarboxylic acid dichloride, and the like, preferably sebacic acid dichloride.

<Graphene oxide layer>
Thin sections of graphene oxide (for example, a thickness of about 1 nm and a length of about 1 to several μm) are thinly laminated on the surface of a porous base film made of a polyketone resin. The thickness of the graphene oxide layer is preferably thick enough not to cause defects (parts without graphene oxide flakes) and thin enough not to cause permeation resistance of the liquid, preferably several nm to 1 μm. More preferably, the graphene oxide layer has a thickness of 10 nm to 500 nm, and more preferably 20 nm to 300 nm. The thickness of the graphene oxide layer can be measured, for example, by observing the cross section of the composite semipermeable membrane with an electron microscope.

Lamination on the surface of the porous substrate membrane can be performed, for example, by filtering a suspension of graphene oxide flakes onto the porous substrate membrane. The thickness of the graphene oxide layer can be controlled by the concentration of graphene oxide in the suspension of the graphene oxide to be filtered and the amount of the filtrate. As the filtration method, for example, suction filtration and pressure filtration can be selected.

It is preferable that the graphene oxide layer contains an amine compound. It is speculated that the amine compound has the effect of stabilizing the laminated structure of the graphene oxide pieces by the electrostatic interaction with the carboxyl group and the like present in the graphene oxide pieces and the hydrogen bond and the covalent bond with the oxygen-containing functional group. To. Examples of the amine compound include triethanolamine, ethylenediamine, butylenediamine, 1,3-propanediamine, hexamethylenediamine, p-phenylenediamine, m-phenylenediamine, m-xylylenediamine, polyethyleneimine, polyallylamine hydrochloride and the like. Can be mentioned. As the amine compound, polyfunctional (diamine, triamine, polyamine) is more preferable than monoamine.

The presence of the amine compound in the graphene oxide layer is, for example, when the graphene oxide flakes are laminated on the surface of the porous substrate film (when the suspension of the graphene oxide flakes is filtered on the porous substrate film). This can be done by adding and dissolving an amine compound in a suspension of graphene oxide flakes and filtering the graphene oxide flakes suspension containing the amine compound onto a porous substrate membrane.

The presence of the amine compound in the graphene oxide layer can be confirmed by detecting nitrogen atoms by, for example, X-ray photoelectron spectroscopy (XPS). The amount of nitrogen atoms in the graphene oxide layer by XPS analysis is preferably about 0.01 to 0.2, more preferably 0.05 to 0.15, in terms of the atomic number ratio (N / C) with carbon atoms. Is.

It is speculated that the amine compound has the effect of stabilizing the laminated structure of the graphene oxide pieces by the electrostatic interaction with the carboxyl group and the like present in the graphene oxide pieces and the hydrogen bond and the covalent bond with the oxygen-containing functional group. It is preferable that a certain amount or more is present in the graphene oxide layer, but on the other hand, it is considered that the amine compound that has entered between the layers of the graphene oxide layer becomes a resistance to liquid permeation, and the amine compound has become a resistance to liquid permeation. It is considered that the abundance of the amine compound has an appropriate range.

It is also possible to confirm the presence of the amine compound from the presence of absorption at a wavelength of 1500 to 1600 cm ^-1 based on the NH bond by an infrared absorption analysis method (FT-IR method or the like).

<Use of composite semipermeable membrane>
The composite semipermeable membrane in the present embodiment can be suitably used for treatments such as separation, purification, and concentration in an aqueous liquid and an organic liquid. Here, the aqueous solution broadly refers to an aqueous solution, and the organic solution refers to a solution in which a solute is dissolved in a general organic solvent, and the solvent is not limited to a specific type.

<Membrane performance evaluation>
The performance of the composite semipermeable membrane can be evaluated by the amount of water permeation, the amount of liquid permeation, and the blocking rate. Here, the water permeation amount and the liquid permeation amount are the water permeation amount or the liquid permeation amount per membrane area of various solutions pressurized in the range of, for example, 2 atm to 5 atm in pressure filtration (unit: ^Lm- . ²・ h ^-1・ Atmospheric pressure ^-1 ). The blocking rate is a value (unit:%) calculated by 1- (supply liquid concentration / permeate liquid concentration) in the above-mentioned pressure filtration of the sodium chloride aqueous solution.

The solution used for the reverse osmosis treatment test was selected from an aqueous solution of sodium sulfate, Evans blue (molecular weight 961), and polyethylene glycol as an aqueous solution. The organic solution was selected from a methanol solution of methyl orange (molecular weight 327), acid red 265 (molecular weight 636), and Evans blue (molecular weight 961).

The organic liquid resistance of the composite semipermeable membrane can be easily confirmed by the visual change in the film shape (whether or not there is a dimensional change due to swelling or the like) when immersed in the organic liquid.

Hereinafter, embodiments of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the embodiments of the present invention are not limited to these Examples. Hereinafter, ppm refers to mass ppm.

(Example 1)
A polyketone resin (extreme viscosity 3.0 dL / g) in which carbon monoxide and ethylene were completely alternately copolymerized was dissolved in a 65% by weight aqueous solution of resorcinol so as to have a thickness of 10% by weight. This polyketone solution was cast on a glass plate to a thickness of 0.4 mm, then immersed in a bath of a 30% by weight aqueous methanol solution, washed with acetone and hexane, and made into a flat film-like porous material made of a polyketone resin. A polyketone base film was obtained. This porous substrate membrane was immersed in a 2.5% by volume 3-aminopropyltriethoxysilane aqueous solution at room temperature for 2 hours and then washed with pure water to obtain a porous substrate membrane made of a polyketone resin. ..

A dispersion was prepared by dispersing graphene oxide flakes prepared by the Improved Hammer's method in pure water at a concentration of 5 ppm (measured by the dynamic light scattering method (measured using Photal ELSZ-1000, manufactured by Otsuka Electronics Co., Ltd.)). Average particle size 1 μm). This dispersion is filtered (suction filtration) in an amount of 7 mL / cm ² per membrane area on the above-mentioned porous substrate membrane, and then heated at 80 ° C. for 1 hour, and the graphene oxide layer is made of a polyketone resin. A film formed by laminating on a porous substrate film was obtained.

Using the obtained film, in order to confirm the performance in an aqueous solution, pressure filtration of 500 ppm sodium sulfate aqueous solution and 10 ppm Evans blue (molecular weight 961) aqueous solution was performed at 2 atm for both solutions. At 25 ° C., the water permeation amount was 21 L, m ^-2 , h ^-1 , atmospheric pressure ^-1 , the inhibition rate of sodium sulfate was zero, and the inhibition rate of Evans blue was 65%.

In addition, in order to confirm the performance of the organic liquid, pressure filtration of a 10 ppm methanol solution of Evans blue (molecular weight 961) was performed at 5 atm and 25 ° C., and the liquid permeation amount was 3.1 Lm. ^-2 , h ^-1 , atmospheric pressure ^-1 , and the blocking rate was 50%.

(Example 2)
A porous substrate in which the graphene oxide layer is made of a polyketone resin in the same manner as in Example 1 except that triethanolamine is dissolved in a dispersion of graphene oxide flakes prepared by the Improved Hammer's method by the same weight as the graphene oxide in the solution. A film laminated on the film was obtained. An electron micrograph (cross section of the membrane near the graphene oxide layer) (measured using JSM-7500F manufactured by JEOL Ltd.) of the obtained membrane is shown in FIG. The thickness of the porous substrate film was about 150 μm, and the thickness of the graphene oxide layer was about 150 nm.

Using the obtained film, in order to confirm the performance in an aqueous solution, a 500 ppm sodium sulfate aqueous solution and a 10 ppm Evans blue (molecular weight 961) aqueous solution were pressure-filtered at 2 atm and 25 ° C. to allow water to pass through. The molecular weight was 4 L, m ^-2 , h ^-1 , atmospheric pressure ^-1 , the inhibition rate of sodium sulfate was 70%, and the inhibition rate of Evans blue was 98%.

In addition, in order to confirm the performance in the organic liquid, pressure filtration of a 10 ppm methanol solution of methyl orange (molecular weight 327), acid red 265 (molecular weight 636) and Evans blue (molecular weight 961) was performed at 2 atm and 25 ° C. The liquid permeation amount was 1 L, m ^-2 , h ^-1 , atmospheric pressure ^-1 , and the blocking rates were 30%, 80%, and 99%, respectively.

(Example 3)
A polyketone resin (extreme viscosity 3.0 dL / g) in which carbon monoxide and ethylene were completely alternately copolymerized was dissolved in a 65% by weight aqueous solution of resorcinol so as to have a thickness of 10% by weight. This polyketone solution was cast on a glass plate to a thickness of 0.4 mm, then immersed in a bath of a 30% by weight aqueous methanol solution, washed with acetone and hexane, and made into a flat film-like porous material made of a polyketone resin. A polyketone base film was obtained. This porous substrate film was immersed in a 0.5 wt% sodium hydride aqueous solution at room temperature for 5 minutes, and then in a hexane solution of 1 wt% sebacic acid dichloride at room temperature for 10 minutes to introduce a carboxyl group. , A porous base film made of a polyketone resin was obtained.

Graphene oxide flakes prepared by the Improved Hammer's method were dispersed in pure water at a concentration of 5 ppm, and then ethylenediamine was added and dissolved at a concentration of 2 ppm to prepare a dispersion (dynamic light scattering method (Otsuka Electronics Co., Ltd., Photal ELSZ). Average particle size 1 μm measured by -1000). This dispersion is filtered (suction filtration) in an amount of 7 mL / cm ² per membrane area on the above-mentioned porous substrate membrane, and then heated at 80 ° C. for 1 hour to form a graphene oxide layer of a polyketone resin. A film formed by laminating on a porous substrate film made of the above was obtained.

When the atomic composition analysis of the graphene oxide layer of the obtained film was performed by XPS (measured using JPS-9010MC manufactured by Nippon Denshi Co., Ltd.), the abundance of carbon, oxygen, and nitrogen as the number of atoms of each was performed. Was 59.9%, 36.7%, and 3.27%, respectively, and the atomic number ratio (N / C) of the nitrogen atom to the carbon atom was 0.055.

Using the obtained film, in order to confirm the performance in an aqueous solution, a 500 ppm sodium sulfate aqueous solution and a 10 ppm Evans blue (molecular weight 961) aqueous solution were pressure-filtered at 2 atm and 25 ° C. to allow water to pass through. The molecular weight was 2.1 L, m ^-2 , h ^-1 , atmospheric pressure ^-1 , the inhibition rate of sodium sulfate was 90%, and the inhibition rate of Evans blue was 98%.

In addition, in order to confirm the performance in the organic liquid, pressure filtration of a 10 ppm methanol solution of methyl orange (molecular weight 327), acid red 265 (molecular weight 636) and Evans blue (molecular weight 961) was performed at 2 atm and 25 ° C. The liquid permeation amount was 0.75 L, m ^-2 , h ^-1 , atmospheric pressure ^-1 , and the blocking rates were 60%, 80%, and 99%, respectively.

(Example 4)
A film formed by laminating a graphene oxide layer on a porous substrate film made of a polyketone resin in the same manner as in Example 3 except that ethylenediamine was not added to the dispersion of graphene oxide flakes prepared by the Improved Hammer's method. Got

When the atomic composition analysis of the graphene oxide layer of the obtained film was performed by XPS (measured using JPS-9010MC manufactured by Nippon Denshi Co., Ltd.), the abundance of carbon, oxygen, and nitrogen as the number of atoms of each was performed. Was 56.1%, 43.0%, and 0.0%, respectively, and the atomic number ratio (N / C) between the nitrogen atom and the carbon atom was zero.

Using the obtained film, in order to confirm the performance in an aqueous solution, a 500 ppm sodium sulfate aqueous solution and a 10 ppm Evans blue (molecular weight 961) aqueous solution were pressure-filtered at 2 atm and 25 ° C. to allow water to pass through. The molecular weight was 7.3 L, m ^-2 , h ^-1 , atmospheric pressure ^-1 , the inhibition rate of sodium sulfate was 20%, and the inhibition rate of Evans blue was 75%.

In addition, in order to confirm the performance in the organic liquid, pressure filtration of a 10 ppm methanol solution of methyl orange (molecular weight 327), acid red 265 (molecular weight 636) and Evans blue (molecular weight 961) was performed at 2 atm and 25 ° C. The liquid permeation amount was 1.7 L, m ^-2 , h ^-1 , atmospheric pressure ^-1 , and the blocking rates were 25%, 35%, and 60%, respectively.

(Example 5)
A polyketone resin (extreme viscosity 3.0 dL / g) in which carbon monoxide and ethylene were completely alternately copolymerized was dissolved in a 65% by weight aqueous solution of resorcinol so as to have a thickness of 10% by weight. This polyketone solution was cast on a glass plate to a thickness of 0.4 mm, then immersed in a bath of a 25 wt% methanol aqueous solution, further washed with acetone and hexane, and a flat film-like porous material made of a polyketone resin. A polyketone base film was obtained.

Graphene oxide flakes prepared by the Improved Hammer's method were dispersed in pure water at a concentration of 400 ppm, ethylenediamine was further added and dissolved at a concentration of 6000 ppm, and then heated at 80 ° C. for 1 hour to obtain a dispersion of graphene oxide. Pure water was added to this dispersion and diluted 80-fold to adjust the graphene oxide flake concentration to 5 ppm and the ethylenediamine concentration to 75 ppm. This dispersion is oxidized by filtering the above-mentioned porous substrate membrane in an amount of 7 mL / cm ² per membrane area (pressure filtration at 1 atm) and then heating at 80 ° C. for 1 hour. A film formed by laminating a graphene layer on a porous substrate film made of a polyketone resin was obtained.

When the atomic composition analysis of the graphene oxide layer of the obtained film was performed by XPS (measured using JPS-9010MC manufactured by Nippon Denshi Co., Ltd.), the abundance of carbon, oxygen, and nitrogen as the number of atoms of each was performed. Was 75.9%, 18.5%, and 5.59%, respectively, and the atomic number ratio (N / C) of the nitrogen atom to the carbon atom was 0.074.

Infrared absorption analysis results (FT-IR method) (measured using Nicolet iS5 manufactured by Thermo Fisher Scientific Co., Ltd.) of the graphene oxide laminated surface of the obtained film and the porous substrate film made of polyketone resin. It is shown in FIG. In the obtained membrane, absorption that could be attributed to the NH bond of the amine compound was observed in the region of wave number 1500 to 1600 cm ^-1 .

Using the obtained film, in order to confirm the performance in an aqueous solution, pressure filtration of a 0.1 wt% aqueous solution of polyethylene glycol having a molecular weight of 200, 600 and 1000 was performed at 2 atm and 25 ° C. The liquid volume was 0.25 L, m ^-2 , h ^-1 , atmospheric pressure ^-1 , and the blocking rates were 60%, 85%, and 98%, respectively.

In addition, in order to confirm the performance in the organic liquid, pressure filtration of a 10 ppm methanol solution of methyl orange (molecular weight 327), acid red 265 (molecular weight 636) and Evans blue (molecular weight 961) was performed at 2 atm and 25 ° C. The liquid permeation amount was 0.06 L, m ^-2 , h ^-1 , atmospheric pressure ^-1 , and the blocking rates were 90%, 99% or more, and 99% or more, respectively.

(Reference example 1)
A film formed by laminating a graphene oxide layer on a porous substrate film made of a polyketone resin in the same manner as in Example 5 except that ethylenediamine was not added to the dispersion of graphene oxide flakes prepared by the Improved Hammer's method. Got

FIG. 2 shows the infrared absorption analysis results (FT-IR method) (measured using Nicolet iS5 manufactured by Thermo Fisher Scientific Co., Ltd.) on the graphene oxide laminated surface of the obtained film.

(Comparative Example 1)
The graphene oxide layer is laminated on the porous substrate film in the same manner as in Example 2 except that a porous film having a pore size of 50 nm made of nitrocellulose (VMWP04700 manufactured by Merck Group) is used as the porous substrate film. Obtained a membrane. When an attempt was made to confirm the performance of the organic liquid in the same manner as in Example 2, the film was swollen by the liquid, so that the measurement was impossible.

The present invention can be used in a wide range of industrial fields such as the field of water treatment such as wastewater purification, and the separation and purification and concentration of valuable resources in various water-based liquids and organic-based liquids in the chemical industry and the pharmaceutical industry.

Claims (2)

A composite semipermeable membrane having a graphene oxide layer on a porous substrate membrane containing a polyketone resin. The composite semipermeable membrane according to claim 1, wherein the graphene oxide layer contains an amine compound.

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