Pervaporation membrane

Abstract

The present invention provides a novel pervaporation membrane suitable for separating a volatile organic compound from an aqueous solution containing the organic compound. This pervaporation membrane (10) is provided with a separation function layer (1). The separation function layer (1) has a matrix (2) containing a silicone resin, and a filler (3) dispersed in the matrix (2) and containing silica. The pervaporation membrane 10 is useful, for example, for separating organic compounds from aqueous solutions containing volatile organic compounds.

Description

Technical Field

[0001] The present invention relates to pervaporation membranes. Background Art

[0002] As a method for obtaining a valuable substance derived from non-petroleum, a method for utilizing fermentation based on microorganisms is known. For example, a method for producing volatile organic compounds (fermentation products) such as alcohol by fermenting carbon sources such as glucose using microorganisms has been developed. The fermentation of the carbon source is carried out, for example, in an aqueous solution. In this method, if the content of the fermentation product in the aqueous solution increases, the fermentation based on microorganisms is sometimes stopped. In order to continuously manufacture the fermentation product based on microorganisms, it is necessary to separate the fermentation product from the aqueous solution.

[0003] As an example of a method for separating a volatile organic compound from an aqueous solution containing the organic compound, a pervaporation method (pervaporation method) using a pervaporation membrane can be cited. The pervaporation method is suitable for separating volatile organic compounds from aqueous solutions containing various substances. Compared with the distillation method, the pervaporation method also tends to suppress energy consumption and carbon dioxide emissions. A specific example of the material of the pervaporation membrane used in the pervaporation method is a silicone resin (for example, Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 4899122 Summary of the invention

[0007] Problems to be solved by the invention

[0008] There is a need for new pervaporation membranes suitable for separating volatile organic compounds from aqueous solutions containing such organic compounds.

[0009] Means for solving problems

[0010] The present invention provides a pervaporation membrane, which is a pervaporation membrane having a separation functional layer.

[0011] The separation function layer includes a matrix containing a silicone resin and a filler containing silica and dispersed in the matrix.

[0012] Effects of the Invention

[0013] According to the present invention, it is possible to provide a novel pervaporation membrane suitable for separating volatile organic compounds from an aqueous solution containing the organic compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] [ Figure 1] is a cross-sectional view schematically showing a permeation vaporization membrane according to one embodiment of the present invention.

[0015] [ Figure 2 ] is a schematic cross-sectional view of a membrane separation device equipped with a pervaporation membrane.

[0016] [ Figure 3 ] is a stereoscopic diagram schematically showing a modified example of the membrane separation device.

[0017] [ Figure 4 ] is a schematic diagram showing an example of a membrane separation system. DETAILED DESCRIPTION

[0018] A pervaporation membrane according to a first aspect of the present invention is a pervaporation membrane having a separation functional layer.

[0019] The separation functional layer includes a matrix containing a silicone resin and a filler containing silica dispersed in the matrix.

[0020] In the second aspect of the present invention, for example, in the pervaporation membrane according to the first aspect, the Hansen solubility parameter of the filler is 20 MPa. 1 / 2 ~27MPa 1 / 2 .

[0021] In a third aspect of the present invention, for example, in the pervaporation membrane according to the first or second aspect, the filler has a surface modified with a modifying group containing a hydrocarbon group.

[0022] In a fourth aspect of the present invention, for example, in the pervaporation membrane according to the third aspect, the modifying group includes at least one selected from the group consisting of an organosilyl group and a polyorganosiloxane group.

[0023] In a fifth aspect of the present invention, for example, in the pervaporation membrane according to any one of the first to fourth aspects, the pH of the dispersion of the filler measured by the following test is 4.0 to 9.0.

[0024] Test: Water, methanol and the filler are mixed to prepare a dispersion, and the pH of the dispersion is measured. In the dispersion, the content of the filler is 4 wt %, the weight ratio of water to methanol is 1:1, and the temperature of the dispersion is 25°C.

[0025] In a sixth aspect of the present invention, for example, in the pervaporation membrane according to any one of the first to fifth aspects, the average particle size of the filler is 1 μm or less.

[0026] In a seventh aspect of the present invention, for example, in the pervaporation membrane according to any one of the first to sixth aspects, the content of the filler in the separation functional layer is less than 70 wt % (weight %).

[0027] In an eighth aspect of the present invention, for example, in the pervaporation membrane according to any one of the first to seventh aspects, the silicone resin is formed of an addition-type silicone resin composition, a condensation-type silicone resin composition, or a UV-curable silicone resin composition.

[0028] In a ninth aspect of the present invention, for example, the pervaporation membrane according to any one of the first to eighth aspects is used to separate a volatile organic compound from an aqueous solution containing the organic compound.

[0029] In a tenth aspect of the present invention, for example, in the pervaporation membrane according to the ninth aspect, the organic compound is a fermentation product produced by a microorganism.

[0030] Hereinafter, the present invention will be described in detail, but the following description is not intended to limit the present invention to specific embodiments.

[0031] <Embodiment of pervaporation membrane>

[0032] like Figure 1 As shown, the pervaporation membrane 10 of the present embodiment includes a separation functional layer 1. The pervaporation membrane 10 is typically a membrane (separation membrane) that preferentially allows a volatile organic compound C to permeate from an aqueous solution S containing the organic compound C. The pervaporation membrane 10 may further include a porous support 5 that supports the separation functional layer 1. The separation functional layer 1 has, for example, a surface that is directly in contact with the porous support 5 and a surface that is exposed to the outside of the pervaporation membrane 10. The pervaporation membrane 10 is, for example, composed only of the separation functional layer 1 and the porous support 5.

[0033] (Separation Functional Layer)

[0034] The separation functional layer 1 is, for example, a layer that allows the organic compound C to preferentially permeate the aqueous solution S, and is typically a dense layer (non-porous layer) in which no pores are observed when observed at a magnification of 5000 times using a scanning electron microscope (SEM).

[0035] The separation function layer 1 comprises a matrix 2 containing a silicone resin and a filler 3 containing silica dispersed in the matrix 2. All or part of the filler 3 is embedded in the matrix 2. In the matrix 2, all the fillers 3 may be separated from each other or partially aggregated.

[0036] As described above, the substrate 2 includes a silicone resin. The silicone resin is formed, for example, from a silicone resin composition. The silicone resin is formed from an addition-type silicone resin composition, a condensation-type silicone resin composition, or a UV-curable silicone resin composition, preferably from an addition-type silicone resin composition. The addition-type silicone resin composition can be cured without using almost any metal species (especially tin) that promotes the hydrolysis of the silicone resin. Therefore, the separation function layer 1 including the silicone resin formed from the addition-type silicone resin composition contains almost no metal species that promotes the hydrolysis of the silicone resin, and tends to have high durability against the above-mentioned aqueous solution S.

[0037] [Addition type silicone resin composition]

[0038] The addition type silicone resin composition is a type of silicone resin composition that is cured by an addition reaction. The addition type silicone resin composition, for example, comprises a polyorganosiloxane P1 having an alkenyl group and a polyorganosiloxane P2 having a hydrosilane (SiH) group. The addition type silicone resin composition preferably further comprises a curing catalyst (hydrosilylation catalyst). It should be noted that the addition type silicone resin composition may be a material in which a curing catalyst is added to a commercially available silicone resin composition. However, the addition type silicone resin composition may not contain a curing catalyst.

[0039] The addition type silicone resin composition can be formed into a silicone resin by, for example, heat-treating the alkenyl group of polyorganosiloxane P1 and the hydrosilyl group of polyorganosiloxane P2 to cause a reaction (hydrosilylation reaction) to proceed. In the hydrosilylation reaction, polyorganosiloxane P2 functions as a crosslinking agent.

[0040] Examples of the alkenyl group in the polyorganosiloxane P1 include vinyl and hexenyl groups. The number of alkenyl groups in the polyorganosiloxane P1 is, for example, 2 or more. The alkenyl group is, for example, located at the terminal of the polyorganosiloxane P1.

[0041] The polyorganosiloxane P1 is, for example, a polyalkylalkylsiloxane such as polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane; a polyalkylarylsiloxane; a polyorganosiloxane such as poly(dimethylsiloxane-diethylsiloxane) into which an alkenyl group is introduced.

[0042] The weight average molecular weight of the polyorganosiloxane P1 is, for example, 1000 or more, 10,000 or more, 100,000 or more, 200,000 or more, 300,000 or more, or 400,000 or more. The larger the weight average molecular weight of the polyorganosiloxane P1, the more the separation characteristics of the pervaporation membrane 10 tend to be improved. The upper limit of the weight average molecular weight of the polyorganosiloxane P1 is not particularly limited, and is, for example, 1,000,000.

[0043] The number of hydrosilyl groups in the polyorganosiloxane P2 is, for example, not less than 2. The hydrosilyl group may be located at the terminal of the polyorganosiloxane P2 or may be included in the main chain of the polyorganosiloxane P2.

[0044] Examples of the polyorganosiloxane P2 include polymethylhydrogensiloxane, poly(dimethylsiloxane-methylhydrogensiloxane), and hydrosilyl-terminated polydimethylsiloxane.

[0045] The weight average molecular weight of the polyorganosiloxane P2 is, for example, 100 or more, and may be 10,000 or more. The larger the weight average molecular weight of the polyorganosiloxane P2, the more the separation characteristics of the pervaporation membrane 10 tend to be improved. The upper limit of the weight average molecular weight of the polyorganosiloxane P2 is not particularly limited, and is, for example, 1,000,000.

[0046] The weight ratio P2 / P1 of polyorganosiloxane P2 to polyorganosiloxane P1 is, for example, 500 wt% or less, 100 wt% or less, 50 wt% or less, 20 wt% or less, 10 wt% or less, or 5 wt% or less. The lower limit of the weight ratio P2 / P1 is, for example, 0.01 wt% or more.

[0047] As a curing catalyst, for example, a platinum-based catalyst can be cited. In other words, the addition-type silicone resin composition may contain a curing catalyst containing platinum. Specific examples of the platinum-based catalyst are chloroplatinic acid, an olefin complex of platinum, an olefin complex of chloroplatinic acid, and the like. As described above, the addition-type silicone resin composition may not contain a curing catalyst.

[0048] The addition type silicone resin composition may contain a compound that generates a catalyst active species that catalyzes an addition reaction when irradiated with active energy rays such as ultraviolet rays (UV). The addition type silicone resin composition containing such a compound can cause an addition reaction by, for example, UV irradiation.

[0049] The addition type silicone resin composition may contain an organic solvent in addition to the above-mentioned components. Examples of the organic solvent include hydrocarbon solvents such as cyclohexane, n-hexane, and n-heptane; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate and methyl acetate; ketone solvents such as acetone and methyl ethyl ketone; and alcohol solvents such as methanol, ethanol, and butanol. The organic solvent may be used alone or in combination of two or more. The addition type silicone resin composition may also be a solvent-free type that does not substantially contain an organic solvent or the like.

[0050] [Condensation type silicone resin composition]

[0051] The condensation type silicone resin composition is a type of silicone resin composition that is cured by a condensation reaction. The condensation type silicone resin composition, for example, comprises a polyorganosiloxane P3 having a silanol (SiOH) group, and a silane compound P4 having functional groups such as an alkoxy group, an alkenyloxy group, an acyloxy group, an amino group, a ketoxime group, and an amide group. The condensation type silicone resin composition may further comprise a curing catalyst or may not comprise a curing catalyst. It should be noted that the condensation type silicone resin composition may also be obtained by adding a curing catalyst to a commercially available silicone resin composition.

[0052] The condensation type silicone resin composition can be formed into a silicone resin by, for example, heat-treating the silanol groups of the polyorganosiloxane P3 and the functional groups of the silane compound P4 to cause a reaction (condensation reaction) to proceed. In the condensation reaction, the silane compound P4 functions as a crosslinking agent.

[0053] The number of silanol groups in the polyorganosiloxane P3 is, for example, 2 or more. The silanol groups are, for example, located at the ends of the polyorganosiloxane P3. In the polyorganosiloxane P3, an alkyl group such as a methyl group or an ethyl group, a phenyl group, etc. may be introduced as a substituent of a side chain.

[0054] The polyorganosiloxane P3 is, for example, a product obtained by introducing a silanol group into the polyorganosiloxane described above with respect to the polyorganosiloxane P1.

[0055] The weight average molecular weight of polyorganosiloxane P3 is, for example, 1000 or more, 10,000 or more, 100,000 or more, 200,000 or more, 300,000 or more, or 400,000 or more. The upper limit of the weight average molecular weight of polyorganosiloxane P3 is not particularly limited, and is, for example, 1,000,000.

[0056] As described above, the silane compound P4 has functional groups such as an alkoxy group, an alkenyloxy group, an acyloxy group, an amino group, a ketoxime group, and an amide group. As an alkoxy group, a methoxy group, an ethoxy group, etc. can be mentioned. As an alkenyloxy group, an isopropenyloxy group, etc. can be mentioned. As an acyloxy group, an acetoxy group, etc. can be mentioned. As an amino group, a dimethylamino group, a diethylamino group, an ethylmethylamino group, etc. can be mentioned. As a ketoxime group, an acetoxime group, a methylethylketoxime group, etc. can be mentioned. As an amide group, an acetamide group, an N-methylacetamide group, an N-ethylacetamide group, etc. can be mentioned. The number of functional groups in the silane compound P4 is, for example, more than 2. In detail, the silane compound P4 preferably contains an alkoxysilyl group as an alkoxy group.

[0057] The silane compound P4 may be a low molecular weight compound having a molecular weight of about 1000 or less, or may be a high molecular weight compound having a polysiloxane skeleton.

[0058] Examples of the curing catalyst include tin catalysts and organic tin catalysts such as dibutyltin dilaurate, dibutyltin diacetate, and dibutyltin dioctoate.

[0059] The condensation type silicone resin composition may contain an organic solvent in addition to the above components. Examples of the organic solvent include the organic solvents described above for the addition type silicone resin composition. The condensation type silicone resin composition may be a solvent-free type that does not contain a solvent such as an organic solvent.

[0060] [UV curable silicone resin composition]

[0061] The UV-curable silicone resin composition is a silicone resin composition of the type that is cured by ultraviolet (UV) irradiation. The UV-curable silicone resin composition undergoes a curing reaction, for example, by free radical polymerization, free radical addition, ionic polymerization, and the like. The UV-curable silicone resin composition that undergoes a curing reaction by free radical polymerization, for example, includes a polyorganosiloxane P5 having a double bond (specifically, a carbon-carbon double bond) derived from an alkenyl group, an acryloyl group, and the like. The UV-curable silicone resin composition that undergoes a curing reaction by free radical addition, for example, includes a polyorganosiloxane P5 having a double bond (specifically, a carbon-carbon double bond) derived from an alkenyl group, an acryloyl group, and the like, and a compound P6 having a functional group such as a thiol group that can undergo free radical addition. The UV-curable silicone resin composition that undergoes a curing reaction by ionic polymerization, for example, includes a polyorganosiloxane P7 having a functional group such as an epoxy group that can undergo ionic polymerization, and a compound that produces a catalyst active species that catalyzes ionic polymerization by UV irradiation.

[0062] According to the UV curable silicone resin composition that undergoes a curing reaction by radical polymerization, for example, double bonds contained in alkenyl groups, acryloyl groups, etc. of the polyorganosiloxane P5 undergo a radical polymerization reaction by UV irradiation, thereby forming a silicone resin.

[0063] Examples of the alkenyl group of the polyorganosiloxane P5 include vinyl and hexenyl groups. The number of alkenyl groups in the polyorganosiloxane P5 is, for example, 2 or more. The alkenyl group is, for example, located at the end of the polyorganosiloxane P5. In the polyorganosiloxane P5, as a substituent of the side chain, an alkyl group such as a methyl group or an ethyl group, a phenyl group, etc. may be introduced.

[0064] The polyorganosiloxane P5 is obtained by introducing a substituent having a double bond, such as an alkenyl group or an acryloyl group, into the polyorganosiloxane described above for the polyorganosiloxane P1, for example.

[0065] The weight average molecular weight of polyorganosiloxane P5 is, for example, 1000 or more, 10,000 or more, 100,000 or more, 200,000 or more, 300,000 or more, or 400,000 or more. The upper limit of the weight average molecular weight of polyorganosiloxane P5 is not particularly limited, and is, for example, 1,000,000.

[0066] According to the UV curable silicone resin composition that undergoes a curing reaction by free radical addition, for example, the functional group capable of free radical addition contained in compound P6 is free radically added to the double bond contained in the alkenyl group, acryloyl group, etc. of polyorganosiloxane P5 by UV irradiation, thereby allowing a free radical addition reaction to proceed and form a silicone resin.

[0067] In compound P6, the functional group capable of radical addition is, for example, a thiol group, an alkylthiol group, etc. Examples of the alkylthiol group include mercaptomethyl and mercaptoethyl groups. The number of the functional groups capable of radical addition in compound P6 is, for example, 2 or more.

[0068] Compound P6 may be a polyorganosiloxane containing a functional group capable of free radical addition. The functional group is, for example, located at the end of the polyorganosiloxane. In the polyorganosiloxane, an alkyl group such as a methyl group or an ethyl group, a phenyl group, etc. may be introduced as a substituent of a side chain.

[0069] Compound P6 is, for example, a compound obtained by introducing a functional group capable of radical addition, such as a thiol group, into the polyorganosiloxane described above with respect to polyorganosiloxane P1.

[0070] The weight average molecular weight of compound P6 is, for example, 1000 or more, 10,000 or more, 100,000 or more, 200,000 or more, 300,000 or more, or 400,000 or more. The upper limit of the weight average molecular weight of compound P6 is not particularly limited, and is, for example, 1,000,000.

[0071] According to the UV curable silicone resin composition that undergoes curing reaction by ion polymerization, for example, by UV irradiation, a catalyst active species that catalyzes ion polymerization is generated, and ion polymerizable functional groups contained in the polyorganosiloxane P7 undergo ion polymerization reaction with each other, thereby forming a silicone resin.

[0072] In the polyorganosiloxane P7, the functional group capable of ion polymerization is, for example, an epoxy group. Examples of the substituent containing the epoxy group include the epoxy group itself, a glycidyl group, a glycidyloxypropyl group, and the like. The number of the functional groups capable of ion polymerization in the polyorganosiloxane P7 is, for example, 2 or more. The functional group capable of ion polymerization is, for example, located at the end of the polyorganosiloxane P7. In the polyorganosiloxane P7, as a substituent of the side chain, an alkyl group such as a methyl group or an ethyl group, a phenyl group, and the like can be introduced.

[0073] The polyorganosiloxane P7 is obtained by, for example, introducing an ion-polymerizable functional group such as an epoxy group into the polyorganosiloxane described above for the polyorganosiloxane P1.

[0074] The weight average molecular weight of polyorganosiloxane P7 is, for example, 1000 or more, 10,000 or more, 100,000 or more, 200,000 or more, 300,000 or more, or 400,000 or more. The upper limit of the weight average molecular weight of polyorganosiloxane P7 is not particularly limited, and is, for example, 1,000,000.

[0075] In addition to the above-mentioned components, the UV-curable silicone resin composition may also contain an organic solvent. Examples of the organic solvent include hydrocarbon solvents such as cyclohexane, n-hexane, and n-heptane; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate and methyl acetate; ketone solvents such as acetone and methyl ethyl ketone; alcohol solvents such as methanol, ethanol, and butanol, etc. The organic solvent may be used alone or in combination of two or more. The UV-curable silicone resin composition may also be a solvent-free type that does not substantially contain an organic solvent or other solvents.

[0076] The base 2 may contain silicone resin as a main component, or may be substantially composed of silicone resin alone. The "main component" refers to the component that is contained in the largest amount by weight in the base 2.

[0077] The content of the matrix 2 in the separation function layer 1 is not particularly limited, and is, for example, 30 wt % to 99 wt %, or 30 wt % to 90 wt %.

[0078] As described above, filler 3 contains silica. Filler 3 containing silica tends to have excellent hydrolysis resistance compared to filler containing zeolite. In addition, filler 3 containing silica tends to increase the free volume of the silicone resin contained in substrate 2. If the free volume of the silicone resin increases, the separation characteristics of pervaporation membrane 10, especially the separation coefficient α of BuOH relative to water, tend to be improved. The free volume of the silicone resin is not particularly limited, and is, for example, 0.260 nm. 3 Above, it can be 0.280nm 3 Above, 0.300nm 3 Above, 0.320nm 3 Above, 0.330nm 3 Above, it can also be 0.340nm 3 The upper limit of the free volume of the silicone resin is, for example, 0.400 nm. 3 Below, it can be 0.380nm 3 Below, it can also be 0.360nm 3 The free volume of the silicone resin can be 0.300nm 3 ~0.400nm3 The free volume of the silicone resin can be determined by the method described below.

[0079] Silica generally refers to silicon dioxide. Filler 3 may be a silica filler containing silicon dioxide as a main component. The silica filler, for example, does not have a crystalline structure. The silica filler, for example, can be made by reacting metallic silicon with oxygen. The silica filler can be made by a sol-gel method, a sedimentation method, an aqueous solution wet method, etc. Filler 3 may be substantially composed only of silicon dioxide.

[0080] The filler 3, especially the silica filler, for example, does not have micropores with a diameter of 2 nm or less. On the other hand, the filler 3 may have mesopores with a diameter of 2 nm to 50 nm, or macropores with a diameter of 50 nm or more.

[0081] The filler 3 preferably has a surface modified by a modifying group containing a hydrocarbon group. In other words, the filler 3 is preferably surface-modified by the modifying group. The surface-modified filler 3 has high dispersibility in the silicone resin and is suitable for suppressing the generation of cracks in the case of preparing the separation functional layer 1, etc.

[0082] The number of carbon atoms of the hydrocarbon group contained in the modifying group is not particularly limited, and is, for example, 1 to 25. The number of carbon atoms of the hydrocarbon group may be 5 or less. The hydrocarbon group may be linear, branched, or cyclic. Examples of the hydrocarbon group include alkyl groups such as methyl and ethyl groups.

[0083] The modifying group may further include a silicon atom, and a hydrocarbon group may be bonded to the silicon atom. The modifying group may include at least one selected from the group consisting of an organosilyl group and a polyorganosiloxane group. Examples of the organosilyl group include triorganosilyl groups such as trimethylsilyl and diorganosilyl groups such as dimethylsilyl. Examples of the polyorganosiloxane group include dimethylpolysiloxane groups, and the like.

[0084] The surface modification using the modifying group can be performed, for example, by reacting a hydroxyl group present on the surface of the filler 3 with a known silane coupling agent.

[0085] Specific examples of surface-modified silica fillers include "AEROSIL (registered trademark) RX series" (RX50, RX200, RX300, etc.), "AEROSIL (registered trademark) RY series" (RY50, RY200, RY200S, etc.), "AEROSIL (registered trademark) NY series" (NY50, NY50L, etc.), "AEROSIL (registered trademark) NAX series" (NAX50, etc.), and "AEROSIL (registered trademark) R series" (R972, R974, R976, etc.) manufactured by Nippon Aerosil.

[0086] From the viewpoint of dispersibility in the silicone resin, the filler 3 is preferably sufficiently surface-modified by the modifying group. In other words, the number of hydroxyl groups present on the surface of the filler 3 is preferably small. Whether the filler 3 is sufficiently surface-modified by the modifying group can be judged, for example, based on the pH of the dispersion of the filler 3 and the Hansen solubility parameter (HSP value) of the filler 3. It should be noted that the Hansen solubility parameter is obtained by dividing the solubility parameter introduced by Hildebrand into three components: the dispersion term δD, the polar term δP, and the hydrogen bond term δH. The details of the Hansen solubility parameters are disclosed in "Hansen Solubility Parameters; A Users Handbook (CRC Press, 2007)" and the like.

[0087] In this embodiment, the pH of the dispersion of filler 3 measured by the following test is, for example, 4.0 to 9.0, or 6.0 to 8.0. The pH of the dispersion is preferably neutral (near pH 7.0). When the pH of the dispersion is neutral, it can be said that the filler 3 is fully surface-modified by the modifying group, and the number of hydroxyl groups present on the surface is small.

[0088] Test: A dispersion was prepared by mixing water, methanol and filler 3, and the pH of the dispersion was measured. Here, the content of filler 3 in the dispersion was 4 wt %, the weight ratio of water to methanol was 1:1, and the temperature of the dispersion was 25°C.

[0089] The HSP value of filler 3 is, for example, 30 MPa. 1 / 2 Below, it can be 27MPa 1 / 2 Below, 26MPa 1 / 2 Below, 25MPa 1 / 2 Below, can also be 24MPa 1 / 2 The lower limit of the HSP value of the filler 3 is, for example, 20 MPa. 1 / 2 The HSP value of filler 3 can be 20MPa 1 / 2 ~27MPa 1 / 2 , can also be 20MPa 1 / 2 ~25MPa 1 / 2 The HSP value of the filler 3 can be determined by the following method. First, 20 solvents with known HSP values ​​are prepared. As the solvent, acetone, methanol, ethanol, butanol, acetonitrile, dimethyl sulfoxide, dipropylene glycol, γ-butyrolactone, N-methyl-2-pyrrolidone, tetrahydrofuran, aniline, acetic acid, benzyl alcohol, ethylene glycol, glycerol, 1-methylimidazole, N-methylformamide, pyridine, salicylaldehyde and 2-aminoethanol can be used.

[0090] Next, add 0.01 g of filler 3 to 20 mL of the prepared solvent and perform ultrasonic treatment for 10 minutes. For each solvent, determine visually whether the filler 3 is dispersed. In detail, when the solvent to which the filler 3 is added is transparent and no insoluble matter can be confirmed visually, it is determined that the filler 3 is dispersed in the solvent. Next, use software for analyzing HSP values ​​(for example, HSPiP (Hansen Solubility Parameters in Practice)) to draw a solvent in which the filler 3 is dispersed in a three-dimensional diagram with the dispersion term δD, the polar term δP, and the hydrogen bond term δH as axes to make a solubility sphere containing the solvent. The δD (MPa) at the center of the solubility sphere is plotted. 1 / 2 )、δP(MPa 1 / 2 ) and δH(MPa 1 / 2 ) is substituted into the following formula, the calculated value δT (MPa 1 / 2 ) is regarded as the HSP value of filler 3.

[0091] δT=(δD 2 +δP 2 +δH 2 ) 1 / 2

[0092] The shape of the filler 3 is, for example, particulate. In this specification, "particulate" includes spherical, ellipsoidal, scaly and fibrous shapes. The filler 3 can also be in powder form. The average particle size of the filler 3 is not particularly limited, for example, it is less than 50μm, it can be less than 20μm, less than 10μm, less than 1μm, less than 500nm, less than 100nm, less than 50nm, less than 30nm, and can also be less than 20nm. The separation functional layer 1 containing the filler 3 with a small average particle size is easy to disperse the stress applied to the separation functional layer 1, and tends to have high adhesion with the porous support body 5. The lower limit of the average particle size of the separation functional layer 1 and the filler 3 is not particularly limited, for example, it is 1nm, and it can also be 5nm.

[0093] The average particle size of the filler 3 can be determined, for example, by the following method. First, a cross section of the separation functional layer 1 is observed using a transmission electron microscope. In the obtained electron microscope image, the area of ​​a specific filler 3 is calculated by image processing. The diameter of a circle having the same area as the calculated area is regarded as the particle size (particle diameter) of the specific filler 3. The particle sizes of any number (at least 50) of fillers 3 are calculated separately, and the average value of the calculated values ​​is regarded as the average particle size of the filler 3.

[0094] The content of the filler 3 in the separation functional layer 1 is, for example, 1 wt% or more, 5 wt% or more, 10 wt% or more, 20 wt% or more, 30 wt% or more, or 40 wt% or more. The upper limit of the content of the filler 3 in the separation functional layer 1 is not particularly limited, for example, less than 70 wt%, or less than 50 wt%. When the content of the filler 3 is less than 50 wt%, there is a tendency to fully suppress the occurrence of defects such as cracks during the preparation of the separation functional layer 1. It should be noted that the separation functional layer 1 does not substantially contain fillers other than the filler 3 containing silica (for example, zeolite particles).

[0095] The surface area D1 of the filler 3 per unit weight of the matrix 2 is not particularly limited, and is, for example, 5 m 2 / g or more, can be 10m 2 / g or more, 20m 2 / g or more, 30m 2 / g or more, 40m 2 / g or more, and can also be 50m 2 The upper limit of the surface area D1 is not particularly limited, but is, for example, 100 m 2 The surface area D1 can be determined based on the BET specific surface area D2 (m 2 / g), the weight W1 (g) of the substrate 2 contained in the separation functional layer 1, and the weight W2 (g) of the filler 3 contained in the separation functional layer 1 are calculated according to the following formulas.

[0096] D1(m 2 / g)=D2(m 2 / g)×W2(g) / W1(g)

[0097] The thickness of the separation functional layer 1 is, for example, 200 μm or less, 100 μm or less, or 80 μm or less. The thickness of the separation functional layer 1 may be 1.0 μm or more, 10 μm or more, or 30 μm or more.

[0098] (Porous Support)

[0099] The porous support 5 includes, for example, a main body 6 and a microporous layer 7 disposed on the main body 6. In the pervaporation membrane 10, the microporous layer 7 is located between the main body 6 and the separation functional layer 1, and is directly in contact with each of the main body 6 and the separation functional layer 1. The porous support 5 is typically an ultrafiltration membrane.

[0100] The main body 6 is, for example, a fiber structure such as a woven fabric or a nonwoven fabric, and is typically a nonwoven fabric. Examples of the fibers contained in the fiber structure include natural fibers such as wood pulp, cotton, and hemp (e.g., Manila hemp); and chemical fibers (synthetic fibers) such as polyester fibers, rayon, vinylon, acetate fibers, polyvinyl alcohol (PVA) fibers, polyamide fibers, polyolefin fibers, and polyurethane fibers. The main body 6 is, for example, a nonwoven fabric made of polyester fibers. The main body 6 has, for example, an average pore size of 1 μm to 50 μm.

[0101] Examples of the material of the microporous layer 7 include fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene, polyarylethersulfones such as polysulfone and polyethersulfone, and polyimide. The microporous layer 7 has an average pore diameter of, for example, 0.01 μm to 0.4 μm.

[0102] The thickness of the porous support 5 is not particularly limited, and may be, for example, 10 μm or more, 50 μm or more, or 100 μm or more. The thickness of the porous support 5 may be, for example, 300 μm or less, or 200 μm or less.

[0103] (Method for manufacturing pervaporation membrane)

[0104] The permeation vaporization membrane 10 can be produced, for example, by forming a separation functional layer 1 on the microporous layer 7 of the porous support 5. In detail, first, a coating liquid containing a material for the separation functional layer 1 is prepared. The coating liquid is, for example, a mixture of a silicone resin composition (an addition-type silicone resin composition, a condensation-type silicone resin composition, or a UV-curable silicone resin composition) and a filler. In this specification, the mixture of the silicone resin composition and the filler is sometimes referred to as a silicone resin composition. Next, a coating film is obtained by applying the coating liquid on the porous support 5. The separation functional layer 1 is formed by curing the coating film. The curing of the coating film can be carried out at room temperature or in a heated environment. The curing of the coating film can also be carried out by irradiation with active energy rays such as UV.

[0105] When the coating film is cured by heating, the heating conditions of the coating film are not particularly limited. For example, the heating temperature of the coating film may be above 80°C, above 90°C, above 100°C, or above 120°C. The higher the heating temperature of the coating film, the more fully the curing reaction of the components in the silicone resin composition proceeds. The upper limit of the heating temperature of the coating film is not particularly limited, for example, 200°C. The heating time of the coating film can be appropriately adjusted according to the composition of the silicone resin composition used.

[0106] (Application of Pervaporation Membrane)

[0107] The permeation vaporization membrane 10 of the present embodiment is suitable for separating organic compound C from an aqueous solution S containing volatile organic compound C. The organic compound C is not particularly limited as long as it is volatile. In this specification, the so-called "volatile organic compound" refers to an organic compound having a boiling point of 20°C to 260°C at atmospheric pressure (101.325 kPa). It should be noted that, when the concentration of organic compound C in the aqueous solution is high, for example, an aqueous phase containing water as the main component and an organic phase having a higher content of organic compound C than the aqueous phase are generated. However, the organic compound C may not generate an aqueous phase and an organic phase.

[0108] The number of carbon atoms in the organic compound C is not particularly limited, and may be, for example, 10 or less, 8 or less, 6 or less, or 4 or less. The lower limit of the number of carbon atoms in the organic compound C may be 1 or 2. The organic compound C may have, for example, a functional group containing an oxygen atom such as a hydroxyl group, a carbonyl group, an ether group, or an ester group. In the organic compound C, the number of functional groups containing an oxygen atom is typically 1.

[0109] As the organic compound C, for example, alcohol, ketone, ester, etc. can be mentioned, typically alcohol. Alcohol can be an alkyl alcohol consisting of only an alkyl group and a hydroxyl group, or an aryl alcohol containing an aryl group and a hydroxyl group. The alkyl alcohol can be any of linear, branched, and cyclic. As the alkyl alcohol, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, isobutanol, tert-butanol, n-pentanol, etc. can be mentioned. As the aryl alcohol, for example, phenol, etc. can be mentioned.

[0110] The ketone may be a dialkyl ketone consisting only of an alkyl group and a carbonyl group. Examples of the dialkyl ketone include methyl ethyl ketone (MEK) and acetone.

[0111] The ester may be a fatty acid alkyl ester consisting only of an alkyl group and an ester group. Examples of the fatty acid alkyl ester include ethyl acetate and the like.

[0112] It should be noted that the organic compound C is not limited to the above compounds and may be an aromatic hydrocarbon such as benzene, toluene, or xylene.

[0113] The aqueous solution S may contain one organic compound C, or may contain two or more organic compounds C. The content of the organic compound C in the aqueous solution S is, for example, 0.5 wt% or more, 1 wt% or more, 2 wt% or more, or 5 wt% or more. The upper limit of the content of the organic compound C is not particularly limited, and is, for example, 50 wt%.

[0114] The organic compound C may be a fermentation product produced by microorganisms fermenting carbon sources, or may be an alcohol (bioalcohol) produced by microorganisms. That is, the aqueous solution S may be a fermentation liquid containing the organic compound C as a fermentation product. However, the aqueous solution S is not limited to the fermentation liquid, and may also be waste liquid or wastewater discharged from chemical equipment, etc.

[0115] The aqueous solution S may contain other components such as microorganisms that generate fermentation products, carbon sources, nitrogen sources, and inorganic ions in addition to water and organic compounds C. The microorganisms that generate fermentation products are typically bacteria. As carbon sources, polysaccharides such as starch and monosaccharides such as glucose may be cited.

[0116] (Pervaporation membrane characteristics)

[0117] The pervaporation membrane 10 of the present embodiment tends to have a high separation coefficient for organic compound C with respect to water. As an example, the separation coefficient α of n-butanol (BuOH) with respect to water of the pervaporation membrane 10 is, for example, 25 or more, 30 or more, 35 or more, or 40 or more. The upper limit of the separation coefficient α is, for example, 100.

[0118] The separation coefficient α can be measured by the following method. While a mixed liquid obtained from BuOH and water is in contact with one side of the pervaporation membrane 10 (e.g., the main surface 10a on the separation functional layer side of the pervaporation membrane 10), the space adjacent to the other side of the pervaporation membrane 10 (e.g., the main surface 10b on the porous support body side of the pervaporation membrane 10) is depressurized to 15 hPa. Thus, a permeating fluid passing through the pervaporation membrane 10 is obtained. The weight ratio of water and the weight ratio of BuOH in the permeating fluid are measured. In the above operation, the content of BuOH in the mixed liquid is 1.0 wt%. The temperature of the mixed liquid in contact with the pervaporation membrane 10 is 30°C. The space adjacent to the other side of the pervaporation membrane 10 is depressurized to 15 hPa. The separation coefficient α can be calculated according to the following formula. Wherein, in the following formula, X A and X B are the weight ratio of BuOH and the weight ratio of water in the mixed liquid respectively. A and Y B They are the weight ratio of BuOH and the weight ratio of water in the permeated fluid that has permeated permeation membrane 10 .

[0119] Separation coefficient α=(Y A / Y B ) / (X A / X B )

[0120] In the measurement conditions of the separation coefficient α, the flux of BuOH passing through the pervaporation membrane 10 is not particularly limited, and is, for example, 0.01 (g / min / m 2)~10.0(g / min / m 2 ).

[0121] In the pervaporation membrane 10 of the present embodiment, there is a tendency for the adhesion between the separation functional layer 1 and the porous support 5 to be large. For example, the peel strength A of the pervaporation membrane 10 measured by the following test is 0.15 N / 20 mm or more.

[0122] Test: The pervaporation membrane 10 was cut into a test piece of 20 mm in width and 150 mm in length. Using the test piece, the separation functional layer 1 was peeled off from the porous support 5 at a peeling angle of 180° and a tensile speed of 300 mm / min.

[0123] In detail, the above test is carried out by the following method. First, the permeation vaporization membrane 10 to be evaluated is cut into a test piece with a width of 20 mm × a length of 150 mm. Then, the entire surface of the porous support 5 possessed by the test piece is overlapped with the acrylic resin test plate via a double-sided tape (for example, No. 5000NS manufactured by Nitto Denko Corporation), and a 2 kg roller is reciprocated once to crimp them. The acrylic resin test plate has a size of, for example, a width of 150 mm × a length of 150 mm. Then, in the direction from one end of the test piece toward the other end, the separation functional layer 1 is peeled off only 90 mm from the porous support 5 by hand. Using a commercially available tensile testing machine, the peeled separation functional layer 1 and one end of the test piece are grasped with a chuck, and the remaining separation functional layer 1 is peeled off from the porous support 5 at a peeling angle of 180° and a tensile speed of 300 mm / min. The average value of the peeling force at this time is determined as the peeling strength A. It should be noted that the initial distance between chucks in the tensile tester was 150 mm. The test was performed in an atmosphere of 25°C.

[0124] The peel strength A is preferably 0.2 N / 20 mm or more, and may be 0.3 N / 20 mm or more, 0.4 N / 20 mm or more, 0.5 N / 20 mm or more, or 0.6 N / 20 mm or more. The upper limit of the peel strength A is not particularly limited, and is, for example, 20 N / 20 mm.

[0125] <Embodiment of membrane separation device>

[0126] like Figure 2 As shown, the membrane separation device 20 of this embodiment includes a pervaporation membrane 10 and a tank 22. The tank 22 has a first chamber 23 and a second chamber 24. The first chamber 23 functions as a supply space to which a supply fluid (specifically, the above-mentioned aqueous solution S) is supplied. The second chamber 24 functions as a permeation space to which a permeated fluid S1 is supplied. The permeated fluid S1 is obtained by the aqueous solution S permeating the pervaporation membrane 10.

[0127] Pervaporation membrane 10 is disposed inside tank 22. Pervaporation membrane 10 partitions first chamber 23 and second chamber 24 inside tank 22. Pervaporation membrane 10 extends from one of a pair of wall surfaces of tank 22 to the other.

[0128] The first chamber 23 has an inlet 23a and an outlet 23b. The second chamber 24 has an outlet 24a. The inlet 23a is an opening for supplying the aqueous solution S to the supply space (the first chamber 23). The outlet 24a is an opening for discharging the permeated fluid S1 from the permeation space (the second chamber 24). The outlet 23b is an opening for discharging the aqueous solution S (non-permeated fluid S2) that has not permeated the permeation vaporization membrane 10 from the supply space (the first chamber 23). Each of the inlet 23a, the outlet 23b, and the outlet 24a is formed, for example, on the wall surface of the tank 22.

[0129] The membrane separation device 20 is suitable for a flow-through (continuous) membrane separation method. However, the membrane separation device 20 can also be used for a batch-type membrane separation method.

[0130] (Method for operating membrane separation device)

[0131] The operation method of membrane separation device 20 is implemented as follows, for example. First, aqueous solution S is supplied to first chamber 23 of membrane separation device 20 through inlet 23a. Thus, aqueous solution S can be brought into contact with one surface (for example, main surface 10a) of pervaporation membrane 10.

[0132] Next, while the aqueous solution S is in contact with one side of the pervaporation membrane 10, the space adjacent to the other side (e.g., the main side 10b) of the pervaporation membrane 10 is decompressed. Specifically, the pressure in the second chamber 24 is reduced through the outlet 24a. The decompression in the second chamber 24 can be performed, for example, by a decompression device such as a vacuum pump. The pressure in the second chamber 24 is, for example, 50 kPa or less, and can be 20 kPa or less, 10 kPa or less, 5 kPa or less, 3 kPa or less, or 2 kPa or less. It should be noted that, in this specification, "pressure" refers to absolute pressure unless otherwise specified.

[0133] By reducing the pressure in the second chamber 24, a permeated fluid S1 having a high content of organic compound C can be obtained on the other side of the pervaporation membrane 10. In other words, the permeated fluid S1 is supplied to the second chamber 24. In the second chamber 24, the permeated fluid S1 is typically a gas. The permeated fluid S1 is discharged to the outside of the membrane separation device 20 through the outlet 24a.

[0134] On the other hand, the content of the organic compound C in the aqueous solution S gradually decreases from the inlet 23a to the outlet 23b of the first chamber 23. The aqueous solution S (non-permeable fluid S2) treated in the first chamber 23 is discharged to the outside of the membrane separation device 20 through the outlet 23b. The non-permeable fluid S2 is typically a liquid.

[0135] As described above, pervaporation membrane 10 can preferentially permeate organic compounds C contained in aqueous solution S. Therefore, permeated fluid S1 obtained by operating membrane separation device 20 has a higher content of organic compounds C than aqueous solution S supplied to membrane separation device 20 .

[0136] <Modification of membrane separation device>

[0137] The membrane separation device 20 may be a spiral membrane element, a hollow fiber membrane element, a coil-type membrane element in which a plurality of pervaporation membranes are stacked, a plate-and-frame membrane element, or the like. Figure 3 A spiral type membrane element is shown. Figure 3 The membrane separation device 25 includes a central tube 26 and a stack 27 . The stack 27 includes a pervaporation membrane 10 .

[0138] The central tube 26 has a cylindrical shape. A plurality of holes or slits are formed on the surface of the central tube 26 for allowing the permeating fluid S1 to flow into the interior of the central tube 26. Examples of the material of the central tube 26 include resins such as acrylonitrile-butadiene-styrene copolymer resin (ABS resin), polyphenylene ether resin (PPE resin), and polysulfone resin (PSF resin); and metals such as stainless steel and titanium. The inner diameter of the central tube 26 is, for example, in the range of 20 to 100 mm.

[0139] Laminated body 27 includes, in addition to pervaporation membrane 10, feed-side flow path material 28 and permeate-side flow path material 29. Laminated body 27 is wound around core tube 26. Membrane separation device 25 may further include an exterior material (not shown).

[0140] As the supply side flow path material 28 and the permeate side flow path material 29, for example, a net, woven fabric or knitted fabric made of a resin obtained from polyethylene, polypropylene, polyethylene terephthalate (PET), polyphenylene sulfide (PPS) or ethylene-chlorotrifluoroethylene copolymer (ECTFE) can be used.

[0141] The membrane separation device 25 can be operated, for example, by the following method. First, the aqueous solution S is supplied to one end of the wound stack 27. The internal space of the central tube 26 is depressurized. As a result, the permeated fluid S1 that has permeated the pervaporation membrane 10 of the stack 27 moves into the interior of the central tube 26. The permeated fluid S1 passes through the central tube 26 and is discharged to the outside. The aqueous solution S (non-permeated fluid S2) treated in the membrane separation device 25 is discharged to the outside from the other end of the wound stack 27.

[0142] <Embodiment of membrane separation system>

[0143] like Figure 4 As shown in FIG. 1 , the membrane separation system 100 of the present embodiment includes the membrane separation device 20 described above. Figure 3 The membrane separation device 25 described above is used instead of the membrane separation device 20.

[0144] The membrane separation system 100 further includes a membrane separation device 20 and a tank 30. The tank 30 stores an aqueous solution S to be supplied to the membrane separation device 20. The tank 30 may be a fermentation tank for producing an organic compound C by fermentation of a carbon source by microorganisms.

[0145] The membrane separation system 100 further includes an aqueous solution supply path 70, a non-permeated fluid discharge path 71, and a permeated fluid discharge path 72. The aqueous solution supply path 70 is a path for supplying the aqueous solution S from the tank 30 to the membrane separation device 20 during operation, and is connected to the outlet 31 of the tank 30 and the inlet 23a of the membrane separation device 20. The aqueous solution supply path 70 is provided with, for example, a pump 50 for controlling the flow rate of the aqueous solution S.

[0146] The non-permeated fluid discharge path 71 is a path for discharging the non-permeated fluid S2 from the membrane separation device 20 during operation, and is connected to the outlet 23b of the membrane separation device 20. For example, a pump 51 for controlling the flow rate of the non-permeated fluid S2 is arranged in the non-permeated fluid discharge path 71. It should be noted that the pump 51 may not be arranged in the non-permeated fluid discharge path 71. The non-permeated fluid discharge path 71 may be connected to the inlet 32 ​​of the tank 30, and may be configured so that the non-permeated fluid S2 is delivered to the tank 30 during operation. That is, during operation, the non-permeated fluid S2 may be mixed with the aqueous solution S in the tank 30 and circulated in the aqueous solution supply path 70 and the non-permeated fluid discharge path 71. When the non-permeated fluid S2 is delivered to the tank 30, the aqueous solution S and the non-permeated fluid S2 are mixed in the tank 30, and the content rate of the organic compound C in the aqueous solution S is reduced. When the tank 30 is a fermentation tank, the fermentation stop by the microorganisms can be suppressed by reducing the content rate of the organic compound C in the aqueous solution S, thereby continuously producing the fermented product.

[0147] The permeate fluid discharge path 72 is a path for discharging the permeate fluid S1 from the membrane separation device 20 during operation, and is connected to the outlet 24a of the membrane separation device 20. For example, a decompression device 52 is arranged in the permeate fluid discharge path 72. The decompression device 52 can reduce the pressure in the permeate space of the membrane separation device 20. The decompression device 52 is preferably a vacuum device such as a vacuum pump. The vacuum pump is typically a gas-transporting vacuum pump, and a reciprocating vacuum pump, a rotary vacuum pump, etc. can be cited. As a reciprocating vacuum pump, a diaphragm type and a swing piston type vacuum pump can be cited. As a rotary vacuum pump, there can be cited: a liquid seal pump; an oil rotary pump (rotary pump); a mechanical booster pump; various dry pumps such as roots type, claw type, screw type, turbine type, and vortex type. The pump as the decompression device 52 can also be provided with a variable speed mechanism for changing the rotation speed, etc. An example of a variable speed mechanism is an inverter that drives the motor of the pump. By controlling the rotation speed of the pump, etc. using a variable speed mechanism, the pressure of the permeate space of the membrane separation device 20 can be appropriately adjusted.

[0148] A heat exchanger for cooling the permeated fluid S1 may be further arranged in the permeated fluid discharge path 72. The gas permeated fluid S1 can be condensed by the heat exchanger. The heat exchanger is, for example, a gas-liquid heat exchanger that performs heat exchange between a cooling medium such as an antifreeze liquid and the gas permeated fluid S1. The heat exchanger may be located between the membrane separation device 20 and the pressure reducing device 52 (on the upstream side of the pressure reducing device 52), or between the pressure reducing device 52 and the recovery unit 40 described later (on the downstream side of the pressure reducing device 52).

[0149] The membrane separation system 100 further includes a recovery unit 40. The recovery unit 40 recovers the permeated fluid S1 sent from the membrane separation device 20 and can store the permeated fluid S1. The recovery unit 40 is, for example, a tank storing the permeated fluid S1. The inlet 41 of the recovery unit 40 is connected to a permeated fluid discharge path 72.

[0150] The membrane separation system 100 may further include a controller 60 for controlling the various components of the membrane separation system 100. The controller 60 is, for example, a DSP (Digital Signal Processor) including an A / D conversion circuit, an input / output circuit, an operation circuit, a storage device, etc. The controller 60 stores a program for properly operating the membrane separation system 100.

[0151] Unless otherwise specified, each path of the membrane separation system 100 is constituted by, for example, a pipe made of metal or resin.

[0152] Example

[0153] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0154] (Example 1)

[0155] First, add 10.5 g of silica filler (AEROSIL RX50, manufactured by Japan Aerosil), 77.1 g of toluene (special grade manufactured by FUJIFILM Wako Pure Chemical Corporation) as a diluent solvent, and 0.65 g of a platinum catalyst (CAT-PL-50T, manufactured by Shin-Etsu Chemical Co., Ltd.) as a curing catalyst to 65 g of a silicone resin composition (manufactured by Shin-Etsu Chemical Co., Ltd., KS-847T, toluene solution, solid content 30 wt%) to prepare a coating liquid (addition type silicone resin composition). The silica filler has a surface modified with a trimethylsilane (TMS) group. Next, a coating film (thickness 500 μm) is obtained by applying the coating liquid on a porous support. As a porous support, RS-50 (a laminate of a PVDF microporous layer and a PET nonwoven fabric) manufactured by Nitto Denko Corporation is used. The coating film was formed on the PVDF microporous layer of RS-50.

[0156] Next, the coating film was heated at 90° C. for 20 minutes to cure, thereby preparing a separation functional layer having a thickness of 50 μm. The content of the filler in the separation functional layer was 35 wt %. Thus, the pervaporation membrane of Example 1 was obtained.

[0157] (Example 2)

[0158] The pervaporation membrane of Example 2 was obtained by the same method as in Example 1 except that the type of filler was changed as shown in Table 2.

[0159] (Example 3)

[0160] To 50 g of a silicone resin composition (KS-847T manufactured by Shin-Etsu Chemical Co., Ltd., toluene solution, solid content 30 wt%), 15 g of a silica filler (AEROSIL RX50 manufactured by Nippon Aerosil), 87 g of toluene as a diluent (special grade manufactured by FUJIFILM Wako Pure Chemical Corporation), and 0.5 g of a platinum catalyst (CAT-PL-50T manufactured by Shin-Etsu Chemical Co., Ltd.) as a curing catalyst were added to prepare a coating liquid (addition-type silicone resin composition). Except for the above, a permeation vaporization membrane of Example 3 was obtained by the same method as Example 1.

[0161] (Example 4)

[0162] To 65 g of a silicone resin composition (YSR3022 manufactured by Momentive Performance Materials Japan LLC), 10.5 g of a silica filler (AEROSIL RX50 manufactured by Japan Aerosil), 82.3 g of toluene (special grade manufactured by FUJIFILM Wako Pure Chemical Corporation) as a diluent solvent, and 1.95 g of a tin-based catalyst (YC6831 manufactured by Momentive Performance Materials Japan LLC) as a curing catalyst were added to prepare a coating liquid (condensation-type silicone resin composition). Except for this, a permeation vaporization membrane of Example 4 was obtained by the same method as Example 1.

[0163] (Example 5)

[0164] The pervaporation membrane of Example 5 was obtained by the same method as in Example 4 except that the type of filler was changed as shown in Table 2.

[0165] (Example 6)

[0166] To 50 g of a silicone resin composition (YSR3022 manufactured by Momentive Performance Materials Japan LLC), 15 g of a silica filler (AEROSIL RX50 manufactured by Japan Aerosil), 91.0 g of toluene (special grade manufactured by FUJIFILM Wako Pure Chemical Corporation) as a diluent, and 1.5 g of a tin-based catalyst (YC6831 manufactured by Momentive Performance Materials Japan LLC) as a curing catalyst were added to prepare a coating liquid (condensation-type silicone resin composition). Except for this, a permeation vaporization membrane of Example 6 was obtained by the same method as Example 1.

[0167] (Example 7)

[0168] Except that the type of filler was changed as shown in Table 2, the pervaporation membrane of Example 7 was obtained by the same method as Example 6.

[0169] (Example 8)

[0170] To 100 g of a silicone resin composition (KS-847T, manufactured by Shin-Etsu Chemical Co., Ltd., toluene solution, solid content 30 wt%), 54 g of toluene (manufactured by FUJIFILM Wako Pure Chemical Corporation, special grade) as a dilution solvent and 1 g of a platinum catalyst (CAT-PL-50T, manufactured by Shin-Etsu Chemical Co., Ltd.) as a curing catalyst were added to prepare a coating liquid (addition-type silicone resin composition). Except for the above, a permeation vaporization membrane of Example 8 was obtained by the same method as Example 1.

[0171] (Example 9)

[0172] To 50 g of a silicone resin composition (KS-847T manufactured by Shin-Etsu Chemical Co., Ltd., toluene solution, solid content 30 wt%), 3.75 g of a silica filler (AEROSIL RX200 manufactured by Nippon Aerosil), 42.0 g of toluene as a diluent (special grade manufactured by FUJIFILM Wako Pure Chemical Corporation), and 0.5 g of a platinum catalyst (CAT-PL-50T manufactured by Shin-Etsu Chemical Co., Ltd.) as a curing catalyst were added to prepare a coating liquid (addition-type silicone resin composition). Except for the above, a permeation vaporization membrane of Example 9 was obtained by the same method as Example 1.

[0173] (Example 10)

[0174] Except that the type of filler was changed as shown in Table 2, the pervaporation membrane of Example 10 was obtained by the same method as Example 9.

[0175] (Example 11)

[0176] To 50 g of a silicone resin composition (KS-847T manufactured by Shin-Etsu Chemical Co., Ltd., toluene solution, solid content 30 wt%), 1.15 g of a silica filler (AEROSIL R972 manufactured by Nippon Aerosil), 31.6 g of toluene as a diluent (special grade manufactured by FUJIFILM Wako Pure Chemical Corporation), and 0.5 g of a platinum catalyst (CAT-PL-50T manufactured by Shin-Etsu Chemical Co., Ltd.) as a curing catalyst were added to prepare a coating liquid (addition-type silicone resin composition). Except for the above, the permeation vaporization membrane of Example 11 was obtained by the same method as Example 1.

[0177] [Free volume of silicone resin]

[0178] The free volume of the silicone resin contained in the pervaporation membranes of Examples 1 to 3 and 8 to 11 was determined by the following method. First, a layer having the same composition and thickness as the separation functional layer of the pervaporation membrane was prepared on a release liner. As the release liner, a release-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Corporation, MRE38) was used. The above layer was prepared on the release surface of the release liner. Next, a self-supporting film of the separation functional layer was prepared by removing the release liner.

[0179] Next, the positron beam source was sandwiched between the self-supporting film and the positron lifetime spectrum of the self-supporting film was measured. 22 A sealed ray source of Na is used as a positron beam source, and a high-speed response photomultiplier tube (BaF2 scintillator) is used as a detector. Furthermore, the number of counts is set to about 6Mcount, and the measurement time is set to 24 hours (ie, about 70count / sec (times / second)). Then, based on the obtained positron lifetime spectrum, the lifetime value of positronium related to the free volume of the silicone resin is analyzed. Software (PALSfit 3.171) is used in the analysis. Then, using the Tao-Eldrup equation, the above-mentioned lifetime value is converted into a free volume pore diameter (the diameter of the sphere when the free volume is assumed to be a sphere), and the free volume is calculated.

[0180] It should be noted that the separation functional layer of Example 8 is composed only of silicone resin, while the separation functional layers of Examples 1 to 3 and 9 to 11 are composed of silicone resin and silica filler. Therefore, according to the above-mentioned measurement method, the total value of the free volume of the silicone resin and the free volume of the silica filler is obtained for Examples 1 to 3 and 9 to 11. Therefore, in Examples 1 to 3 and 9 to 11, the above-mentioned measurement method is also implemented on the silica filler itself used, thereby determining the free volume of the silica filler. The free volume of the silicone resin is determined based on the obtained results and the content (vol%) of the silica filler in the separation functional layer. It should be noted that the content (vol%) of the silica filler in the separation functional layer can be determined based on the content (wt%) of the silica filler and the density (g / cm 3 ) is calculated.

[0181] [Surface area of ​​filler per unit weight of substrate D1]

[0182] For the pervaporation membranes of Examples 1 to 7 and 9 to 11, the BET specific surface area D2 (m 2The surface area D1 (m2) of the filler per unit weight of the substrate is calculated based on the above calculation formula, using the weight W1 (g) of the substrate (silicone resin) contained in the separation functional layer, and the weight W2 (g) of the filler contained in the separation functional layer. 2 / g).

[0183] [HSP value of filler]

[0184] The HSP value of the fillers used in Examples 1 to 7 and 9 to 11 was determined by the above-mentioned method. HSPiP was used for the analysis of the HSP value. Table 1 shows the measurement results of the dispersibility of the filler in each solvent.

[0185] [Table 1]

[0186] RX50 RY50 RX200 RY200 R972 acetone × × ○ ○ × Methanol × × × ○ × Ethanol × × ○ × × Butanol ○ ○ × × ○ Acetonitrile × × × × × Dimethyl sulfoxide × × ○ × ○ Dipropylene glycol ○ ○ ○ ○ ○ γ-Butyrolactone × × ○ ○ ○ N-Methyl-2-pyrrolidone ○ ○ ○ ○ ○ Tetrahydrofuran ○ ○ ○ ○ × aniline × × × × × Acetic acid × × ○ × × Benzyl alcohol × × × × × Ethylene glycol × × × × × glycerin × × × × × 1-Methylimidazole ○ × ○ × ○ N-Methylformamide × × ○ ○ ○ Pyridine ○ × × × ○ Salicylaldehyde × × × × × 2-Aminoethanol × × × × ○

[0187] ○: no insoluble matter, ×: insoluble matter

[0188] [pH of filler dispersion]

[0189] For the fillers used in Examples 1 to 7 and 9 to 11, dispersions were prepared by the above-mentioned method, and the pH of the dispersions was measured.

[0190] [PV performance]

[0191] For the pervaporation membranes of Examples 1 to 11, the separation coefficient α of n-butanol (BuOH) relative to water was measured by the following method. First, the pervaporation membrane was cut into a size of 74 mm in diameter to form a flat film-shaped test piece. The test piece was set in an intermittent membrane separation device (unit). A mixed liquid obtained by n-butanol (BuOH) and water was supplied to the supply space of the unit. The content of BuOH in the mixed liquid was 1.0 wt%.

[0192] Next, the cell was immersed in a water bath, and the temperature of the mixed liquid was adjusted to 30°C. Next, the mixed liquid was stirred using a stirrer disposed in the cell, while the pressure in the permeation space was reduced to 15 hPa. Thus, the mixed liquid permeated through the pervaporation membrane to obtain a gaseous permeation fluid. The gaseous permeation fluid was cooled by a cooling trap using liquid nitrogen to condense the permeation fluid. The composition of the liquid permeation fluid was analyzed using gas chromatography, and the separation coefficient α was calculated based on the obtained results.

[0193] [Adhesion]

[0194] The peel strength A of the pervaporation membranes of Examples 1 to 3 and 8 to 11 was measured by the above-mentioned method. As a tensile tester, Autograph AGS-50NX manufactured by Shimadzu Corporation was used.

[0195] [Table 2]

[0196]

[0197] The abbreviations in Tables 1 and 2 are as follows.

[0198] KS847T: Silicone resin composition (manufactured by Shin-Etsu Chemical Co., Ltd., KS-847T)

[0199] YSR3022: Silicone resin composition (Momentive Performance Materials Japan LLC, YSR3022)

[0200] RX50: Silica filler (made by Japan Aerosil, AEROSIL RX50, surface modification group: trimethylsilane (TMS) group)

[0201] RY50: Silica filler (made by Japan Aerosil, AEROSIL RY50, surface modification group: dimethyl polysiloxane (PDMS) group)

[0202] RX200: Silica filler (made by Japan Aerosil, AEROSIL RX200, surface modification group: trimethylsilane (TMS) group)

[0203] RY200: Silica filler (made by Japan Aerosil, AEROSIL RY200, surface modification group: dimethyl polysiloxane (PDMS) group)

[0204] R972: Silica filler (made by Japan Aerosil, AEROSIL R972, surface modification group: dimethylsilane (DMS) group)

[0205] As can be seen from Table 2, for the pervaporation membranes of Examples 1 to 7 and 9 to 11 having a substrate containing a silicone resin and a filler containing silica, the separation coefficient α of n-butanol relative to water is a higher value than that of Example 8. Based on this result, it can be said that the pervaporation membranes of Examples 1 to 7 and 9 to 11 are suitable for separating volatile organic compounds from aqueous solutions containing the organic compounds. It should be noted that, according to the results of Examples 1 to 3 and 8 to 11, the free volume of the silicone resin is increased by adding a filler containing silica. Furthermore, according to the results of Examples 1 to 3 and 8 to 11, the adhesion between the separation functional layer and the porous support is improved by adding a filler.

[0206] Industrial Applicability

[0207] The pervaporation membrane of the present embodiment is suitable for separating volatile organic compounds from an aqueous solution containing the organic compounds.

Claims

1. A pervaporation membrane having a separation functional layer, The separation function layer includes a matrix containing a silicone resin and a filler containing silica dispersed in the matrix.

2. The pervaporation membrane according to claim 1, wherein: The Hansen solubility parameter of the filler is 20 MPa 1 / 2 ~27MPa 1 / 2 .

3. The pervaporation membrane according to claim 1, wherein: The filler has a surface modified with a modifying group including a hydrocarbon group.

4. The pervaporation membrane according to claim 3, wherein: The modifying group includes at least one selected from the group consisting of an organosilyl group and a polyorganosiloxane group.

5. The pervaporation membrane according to claim 1, wherein: The pH of the dispersion of the filler measured by the following test is 4.0 to 9.0, Test: water, methanol and the filler are mixed to prepare a dispersion, and the pH of the dispersion is measured; wherein, in the dispersion, the content of the filler is 4wt%, the weight ratio of water to methanol is 1:1, and the temperature of the dispersion is 25°C.

6. The pervaporation membrane according to claim 1, wherein: The average particle size of the filler is less than 1 μm.

7. The pervaporation membrane according to claim 1, wherein: The content of the filler in the separation function layer is less than 70 wt %.

8. The pervaporation membrane according to claim 1, wherein: The silicone resin is formed of an addition-type silicone resin composition, a condensation-type silicone resin composition, or a UV-curable silicone resin composition.

9. The pervaporation membrane of claim 1, which is used to separate volatile organic compounds from an aqueous solution containing the organic compounds.

10. The pervaporation membrane according to claim 9, wherein: The organic compound is a fermentation product produced by microorganisms.

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