JP6466696B2 - Composite separation membrane and separation membrane element using the same - Google Patents

Description

  The present invention relates to a composite separation membrane comprising a porous support and a separation functional layer formed thereon, and a separation membrane element comprising the composite separation membrane.

  A separation membrane that separates a liquid substrate (for example, water) from a dissolved material (for example, salts) is used for the production of pure water, desalination of brine such as seawater, and wastewater treatment. One type of separation membrane is a composite separation membrane comprising a porous support and a separation functional layer formed on the porous support. The separation functional layer is selected from organic compounds such as polyamide, polysulfone and cellulose acetate depending on the use of the composite separation membrane. As a composite separation membrane, a membrane composed of polyamide formed by a reaction between a polyfunctional amine and a polyfunctional acid halide is known.

  Currently, there is a demand for composite separation membranes with further improved separation characteristics. In particular, in recent years, the use of wastewater treatment or pretreatment for seawater desalination, in which the size of the substrate flux (hereinafter simply referred to as “permeate flux”) is preferentially required over the rejection rate of dissolved substances There is a strong demand to improve the separation characteristics to meet the requirements. In addition, there is always a demand for increasing the permeation flux of the composite separation membrane in order to reduce the operating energy of the apparatus (energy saving).

  Patent Document 1 discloses a composite half provided with a separation functional layer of a crosslinked polyamide by reaction of a mixture of a polyfunctional acid halide and a polyfunctional acid anhydride halide with a mixture of an aliphatic polyfunctional amine and an aromatic polyfunctional amine. A permeable membrane is disclosed. Patent Document 1 describes that the composite semipermeable membrane has high solute removal properties and high water permeability.

JP 2000-33243 A

  In the conventional composite separation membrane including the composite semipermeable membrane disclosed in Patent Document 1, the size of the permeation flux is still insufficient. One of the objects of the present invention is a composite separation membrane comprising a porous support and a separation functional layer formed on the porous support, and maintains the rejection rate of dissolved substances contained in the liquid to be separated. On the other hand, it is to provide a composite separation membrane having further improved permeation flux.

  The composite separation membrane of the present invention comprises a porous support and a separation functional layer formed on the porous support, the separation functional layer comprising an aromatic polyfunctional amine and an aliphatic polyfunctional amine. And a polyamide formed by the reaction of a compound group containing a polyfunctional acid halide, and the ratio of the aromatic polyfunctional amine in the polyfunctional amine in the compound group is 1 mol% or more and less than 5 mol% is there.

  The separation membrane element of the present invention includes the composite separation membrane of the present invention.

  According to the present invention, a composite separation membrane comprising a porous support and a separation functional layer formed on the porous support, while maintaining the rejection rate of the lysate contained in the separation target liquid, A composite separation membrane with further improved permeation flux is obtained.

It is a perspective view which shows typically an example of the separation membrane element of this invention.

  The composite separation membrane of the present invention comprises a porous support and a separation functional layer formed on the porous support. The separation functional layer is composed of a polyamide formed by the reaction of a compound group including an aromatic polyfunctional amine (A), an aliphatic polyfunctional amine (B), and a polyfunctional acid halide. Here, in the compound group, the ratio of the aromatic polyfunctional amine (A) in the polyfunctional amine is 1 mol% or more and less than 5 mol%.

  This polyamide has structural units formed by reacting polyfunctional amines (A) and (B) with polyfunctional acid halides, more specifically, polymerizing (polycondensation). Among these, the structural unit (C) formed by the reaction of the aliphatic polyfunctional amine (B) and the polyfunctional acid halide, and the reaction of the aromatic polyfunctional amine (A) and the polyfunctional acid halide. In the structural unit (D), the former tends to be more flexible and the latter tends to be more rigid. For this reason, due to the presence of the structural unit (D), a partially rigid part in the polyamide molecular chain, in other words, a part where the molecular chain is difficult to move, is generated, and this part is appropriately present in the polyamide molecular chain. As a result, it is possible to obtain a composite separation membrane that further improves the permeation flux while maintaining the rejection rate of the dissolved substances contained in the liquid to be separated. And in the compound group which forms polyamide, when the ratio of the aromatic polyfunctional amine (A) in the polyfunctional amine is 1 mol% or more and less than 5 mol%, the structural unit (D) in the molecular chain of the polyamide The “moderate presence” is achieved. If the ratio is less than 1 mol%, the permeation flux is not improved, and if it is 5 mol% or more, the permeation flux decreases.

  The ratio of the aliphatic polyfunctional amine (B) in the polyfunctional amine in the compound group is more than 95 mol% and 99 mol% or less.

  The polyfunctional amine is an amine having two or more reactive amino groups, for example, a diamine having two reactive amino groups. The compound group may contain 2 or more types of aromatic polyfunctional amines (A), and may contain 2 or more types of aliphatic polyfunctional amines (B).

  The aromatic polyfunctional amine (A) is not particularly limited. For example, m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene. , 3,5-diaminobenzoic acid, 2,4-diaminotoluene, 2,6-diaminotoluene, N, N′-dimethyl-m-phenylenediamine, 2,4-diaminoanisole, amidol, and xylylenediamine At least one kind. The aromatic polyfunctional amine (A) is preferably at least one selected from m-phenylenediamine, p-phenylenediamine and o-phenylenediamine, and more preferably m-phenylenediamine. Moreover, when a compound group contains 2 or more types of aromatic polyfunctional amines (A), it is preferable that m-phenylenediamine is included as the said polyfunctional amine (A).

  The aliphatic polyfunctional amine (B) is, for example, an alicyclic polyfunctional amine. In this case, the permeation flux can be improved at a higher level by the combination with the aromatic polyfunctional amine (A).

  The alicyclic polyfunctional amine (B) is not particularly limited, and is selected from, for example, 1,3-diaminocyclohexane, 1,2-diaminocyclohexane, 1,4-diaminocyclohexane, and piperazine and derivatives thereof. At least one. The alicyclic polyfunctional amine (B) is preferably piperazine or a piperazine derivative. Here, the piperazine derivative means a compound in which at least one hydrogen atom bonded to a carbon atom or a nitrogen atom of piperazine is substituted with a substituent. A substituent is a C1-C4 alkyl group, an amino group, and a hydroxyl group, for example. In addition, since it is a polyfunctional amine, when the hydrogen atom couple | bonded with the nitrogen atom is substituted, the said substituent is an amino group. The piperazine derivative is at least one selected from, for example, 2,5-dimethylpiperazine and 4-aminomethylpiperazine.

  The polyfunctional acid halide is an acid halide having two or more reactive carbonyl groups. The polyfunctional acid halide may be an aromatic polyfunctional acid halide or an aliphatic polyfunctional acid halide. The aliphatic polyfunctional acid halide may be an alicyclic polyfunctional acid halide. The compound group may contain two or more polyfunctional acid halides. When the compound group includes a polyfunctional acid halide having a valence of 3 or more, a separation functional layer composed of a polyamide having a crosslinked structure can be formed.

  The aromatic polyfunctional acid halide is not particularly limited, and examples thereof include trimesic acid trichloride, terephthalic acid dichloride, isophthalic acid dichloride, biphenyl dicarboxylic acid dichloride, naphthalene dicarboxylic acid dichloride, benzene trisulfonic acid trichloride, benzene disulfonic acid dichloride, and chloro. It is at least one selected from sulfonylbenzene dicarboxylic acid dichloride.

  The aliphatic polyfunctional acid halide is not particularly limited. For example, propanedicarboxylic acid dichloride, butanedicarboxylic acid dichloride, pentanedicarboxylic acid dichloride, butanetricarboxylic acid trichloride, butanetricarboxylic acid trichloride, pentanetricarboxylic acid trichloride, glutaryl halide. , Adipoyl halide, and alicyclic polyfunctional acid halide described below.

  The alicyclic polyfunctional acid halide is not particularly limited. For example, cyclopropanetricarboxylic acid trichloride, cyclobutanetetracarboxylic acid tetrachloride, cyclopentanetricarboxylic acid trichloride, cyclopentanetetracarboxylic acid tetrachloride, cyclohexanetricarboxylic acid trichloride, It is at least one selected from tetrahydrofurantetracarboxylic acid tetrachloride, cyclopentanedicarboxylic acid dichloride, cyclobutanedicarboxylic acid dichloride, cyclohexanedicarboxylic acid dichloride, and tetrahydrofurandicarboxylic acid dichloride.

  The structure of the porous support is not limited as long as the separation functional layer can be formed thereon. The porous support is, for example, an ultrafiltration membrane in which a microporous layer is formed on a nonwoven fabric. The average pore diameter of the microporous layer is, for example, about 0.01 to 0.4 μm. The material of the microporous layer is, for example, polyarylethersulfone such as polysulfone or polyethersulfone; polyimide; polyvinylidene fluoride. Of these, polysulfone and polyarylethersulfone are preferred because of their high chemical, mechanical and thermal stability. The porous support may be a self-supporting support composed of a thermosetting resin such as an epoxy resin. In this case, the porous support has an average pore diameter of, for example, 0.01 to 0.4 μm. Have The thickness of a porous support body is not specifically limited, For example, it is 10-200 micrometers, Preferably it is 20-75 micrometers.

  The method for forming the separation functional layer on the porous support is not particularly limited, and a known method can be employed. Examples of the method for forming the separation functional layer include an interfacial condensation method, a phase separation method, and a thin film coating method. In the interfacial condensation method, an amine aqueous solution containing a polyfunctional amine is brought into contact with an acid halide organic solution containing a polyfunctional acid halide, so that the reaction between the polyfunctional amine and the polyfunctional acid halide at the contact surface (interface) ( This is a method for forming a separation functional layer composed of polyamide by advancing polycondensation). Formation of the separation functional layer by this interfacial condensation can be performed on the porous support, and in this case, the separation functional layer is directly formed on the porous support. Of course, a separation functional layer formed at a place other than on the porous support, for example, on the transfer substrate, may be placed on the porous support. Details of the interfacial condensation method are described in, for example, JP-A-58-24303 and JP-A-1-180208, and the conditions described in these known documents can be appropriately employed. Also in the phase separation method and the thin film coating method, methods described in known literatures can be employed.

  The separation functional layer is formed by applying an aqueous amine solution containing a polyfunctional amine component on a porous support to form an aqueous solution coating layer, and then applying an acid halide organic solution containing a polyfunctional acid halide to the porous support. It is preferably formed by contacting with the coating layer and advancing interfacial polymerization.

  In this method, the concentration of the polyfunctional amine in the aqueous amine solution is not particularly limited, and is, for example, 0.1 to 10% by weight, preferably 1 to 4% by weight. In this method, the concentration of the polyfunctional acid halide in the acid halide organic solution is not particularly limited, and is, for example, 0.01 to 5% by weight, preferably 0.05 to 3% by weight.

  The organic solvent used in the acid halide organic solution is not particularly limited as long as the solubility in water is low, the porous support is not deteriorated, and the polyfunctional acid halide is dissolved. For example, saturation such as cyclohexane, heptane, octane, nonane, etc. Hydrocarbon: Halogen-substituted hydrocarbon such as 1,1,2-trichlorotrifluoroethane. The organic solvent is preferably a saturated hydrocarbon having a boiling point of 300 ° C. or lower, more preferably a saturated hydrocarbon having a boiling point of 200 ° C. or lower.

  The time from application of the aqueous amine solution to the application of the acid halide organic solution on the porous support depends on the composition and viscosity of the aqueous amine solution and the pore size of the surface of the porous support. About 2 to 120 seconds, more preferably 2 to 40 seconds, and particularly preferably 2 to 10 seconds. If the coating interval between the two is excessively long, the aqueous amine solution penetrates and diffuses deeply into the porous support before the acid halide organic solution is applied, so that the unreacted polyfunctional amine is porous supported. May remain in large quantities in the body. Moreover, the unreacted polyfunctional amine that has penetrated deep inside the porous support tends to be difficult to remove by subsequent washing treatment. On the other hand, if the coating interval between the two becomes excessively short, the aqueous amine solution hardly penetrates into the porous support until the application of the acid halide organic solution, and there is an excess aqueous amine solution on the porous support. The characteristics of the separated functional layer may be deteriorated.

  In this method, after contacting the coating layer of the aqueous amine solution formed on the porous support and the acid halide organic solution, the excess organic solution present on the porous support is removed and the porous support is removed. It is preferable to form a separation functional layer by heating and drying a film formed on the body. By mechanical drying, the mechanical strength and heat resistance of the separation functional layer can be increased. The temperature of heat drying is, for example, 70 to 200 ° C, and preferably 80 to 130 ° C. The heating time is, for example, about 30 seconds to 10 minutes, and preferably about 40 seconds to 7 minutes.

  In addition to the polyfunctional amines (A), (B) and polyfunctional acid halides, the compound group has various additions for the purpose of facilitating the formation of a separation functional membrane and improving the properties of the resulting composite separation membrane. An agent can be included. The additive may be contained in, for example, an aqueous amine solution and / or an acid halide organic solution in the interfacial condensation method. Depending on the type of the additive, it remains in the formed separation functional layer, and contributes to, for example, improving the characteristics of the composite separation membrane.

  The additive is, for example, a hydrophilic polymer. That is, the compound group may further contain a hydrophilic polymer. The hydrophilic polymer is, for example, at least one selected from polyvinyl alcohol, polyvinyl pyrrolidone, and polyacrylic acid, and polyvinyl alcohol is preferable. When the separation functional layer is formed by the interfacial condensation method, the polyfunctional amine aqueous solution may contain a hydrophilic polymer such as polyvinyl alcohol. The hydrophilic polymer is copolymerized with a polyfunctional amine and a polyfunctional acid halide to improve the hydrophilicity of the surface and inside of the formed separation functional layer. Thereby, the permeation flux of the composite separation membrane can be further improved. The amount of the additive added is preferably about 0.01 to 20% by weight, and more preferably 0.05 to 5% by weight.

Other additives include, for example, surfactants such as sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, and sodium lauryl sulfate that improve the wettability of the solution to the porous support; polyfunctional amines and polyfunctional acid halides Basic compounds such as sodium hydroxide, trisodium phosphate and triethylamine for removing hydrogen halide produced by the reaction; acylation catalysts for the reaction; solubility parameters described in JP-A-8-224452 Is a compound of 8 to 14 (cal / cm ³ ) ^1/2 . These compounds may be added to the aqueous amine solution as necessary.

  For example, the additive is a salt of a tetraalkylammonium halide or trialkylammonium and an organic acid. This salt has effects such as making the separation functional layer easier to form, improving the absorbability of the aqueous amine solution to the porous support, and promoting the reaction between the polyfunctional amine and the polyfunctional acid halide. What is necessary is just to add this salt to amine aqueous solution as needed.

  The thickness of the separation functional layer is not particularly limited, and is usually about 0.05 to 2 μm, preferably 0.1 to 1 μm. The thickness of the separation functional layer is preferably uniform.

  The shape of the separation functional layer is not particularly limited. One separation functional layer formed on a porous support may be used, or a separation functional layer having a “double pleated structure” described in JP 2011-189340 A may be used.

  The separation functional layer is a layer made of polyamide. As long as the effect of the present invention is obtained, the separation functional layer may contain a material other than polyamide. At this time, the separation functional layer is a layer mainly composed of polyamide. The main component is a component having the largest content, and the content is usually 50% by weight or more, and more preferably 60% by weight, 70% by weight, 80% by weight, 90% by weight or more. . The separation functional layer may be a layer made of polyamide.

  The composite separation membrane of the present invention may be a membrane further subjected to chlorination. The permeation flux of the composite separation membrane is further improved by removing the unstable part of the polyamide in the chlorination. Moreover, in the composite separation membrane of this invention, the fall of the rejection rate of the melt | dissolution by chlorination is suppressed.

  A well-known method is employable for chlorination. For example, chlorination can be carried out by bringing an aqueous solution containing free chlorine into contact with the separation functional layer. The aqueous solution containing free chlorine is not particularly limited, and is, for example, an aqueous solution of a chlorine compound having an action of generating free chlorine in water such as sodium hypochlorite and calcium chloride. The concentration of the chlorine compound in the aqueous solution is preferably about 100 to 1000 mg / L, and the free chlorine concentration at that time is about 10 to 1000 ppm. The conditions for the chlorination are not particularly limited and can be controlled according to the free chlorine concentration of the aqueous solution, the material of the separation functional layer, etc. For example, the treatment time is controlled in the range of 10 minutes to 100 hours. The specific method of bringing the aqueous solution into contact with the separation functional layer is not particularly limited. For example, the composite separation membrane is immersed in the aqueous solution, the aqueous solution is applied or sprayed on the separation functional layer, or the aqueous solution is applied to the composite separation membrane. There is a way to let water through. When passing water, it is preferable to apply a pressure of about 1 to 5 MPa to the aqueous solution and pressurize the water.

  A coating layer may be provided on the surface of the composite separation membrane of the present invention. The coating layer is, for example, a nonionic hydrophilic layer and is a layer composed of a polymer. When the coating layer which is a hydrophilic layer is provided, the permeation flux of the composite separation membrane is further improved by improving the hydrophilicity of the composite separation membrane surface. The coating layer is preferably provided on the surface of the composite separation membrane on the separation functional layer side.

  The polymer used for the coating layer is not particularly limited as long as it does not dissolve the separation functional layer and the porous support and does not dissolve when the composite separation membrane is used (for example, during water treatment). The polymer is, for example, at least one selected from polyvinyl alcohol, polyvinyl pyrrolidone, hydroxypropyl cellulose, polyethylene glycol, and a saponified ethylene-vinyl acetate copolymer. The polymer is preferably polyvinyl alcohol, particularly preferably polyvinyl alcohol having a saponification degree of 99% or more. The coating layer can be formed on the surface of the composite separation membrane by, for example, immersing the composite separation membrane in a solution in which the polymer is dissolved and drying it.

  The coating layer may have a crosslinked structure with the polyamide constituting the separation functional layer. In this case, the elution of the coating layer when using the composite separation membrane can be suppressed. The coating layer having a crosslinked structure with polyamide is, for example, a layer containing polyvinyl alcohol having a saponification degree of 90% or more. The method for crosslinking polyvinyl alcohol and polyamide is not particularly limited. For example, a composite separation membrane in which a polyvinyl alcohol layer is formed on the surface of the separation functional layer may be immersed in a hydrochloric acid-containing polyvalent aldehyde solution. The polyvalent aldehyde is, for example, a dialdehyde such as glutaraldehyde or terephthalaldehyde. An organic crosslinking agent such as an epoxy compound and a polyvalent carboxylic acid and / or an inorganic crosslinking agent such as a boron compound may be used as a crosslinking agent instead of or together with the polyvalent aldehyde.

  The rejection rate (salt rejection rate) exhibited by the composite separation membrane of the present invention is a value at an operating pressure of 1.0 MPa with respect to an aqueous magnesium sulfate solution (concentration 0.20 wt%, pH 6.5, temperature 25 ° C.), for example, It is 95% or more, and can be 96% or more, 97% or more, 98% or more, or 99% or more depending on the composition of polyamide, the presence or absence of chlorination, and the type and amount of additives.

The permeation flux exhibited by the composite separation membrane of the present invention is, for example, 1.5 (m ³ / (m ² · day)) or more when the operating pressure is 1.0 MPa. 1.6 (m ³ / (m ² · day)) or more, 1.8 (m ³ / (m ² · day)) or more, 2.0 (m ³ / (M ² · day)) or more, 2.2 (m ³ / (m ² · day)) or more, and further 2.5 (m ³ / (m ² · day)) or more. Also, the rejection rate can be achieved at the same time.

  The composite separation membrane of the present invention is generally processed into a form of a separation membrane element and used in a state of being loaded in a pressure vessel (vessel). For example, as shown in FIG. 1, the spiral membrane element is formed around a central pipe (water collecting pipe) 35 in a state where a composite separation membrane 31, a supply-side flow path member 32, and a permeate-side flow path member 33 are laminated. A laminate 30 wound in a spiral shape is provided. The membrane element is manufactured by fixing the laminate 30 with an end member and an exterior material.

  The composite separation membrane of this invention can be used for the same use as the conventional composite separation membrane. The application is, for example, use as a reverse osmosis (RO) membrane, ultrafiltration (NF) membrane, microfiltration (MF) membrane, forward osmosis (FO) membrane. More specific applications include, for example, production of pure water or ultrapure water, desalination of brine such as seawater, removal of harmful components or recovery of useful components, concentration or recovery of active ingredients in the food or pharmaceutical field. It can be used for advanced processing.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the examples shown below.

  First, a method for evaluating the composite separation membrane produced in this example is shown.

[Blocking rate]
The rejection rate (salt rejection rate) of the produced composite separation membrane was determined as follows. A magnesium sulfate (MgSO ₄ ) aqueous solution (concentration 0.20 wt%, temperature 25 ° C., pH 6.5) was permeated through the composite separation membrane at an operating pressure of 1.0 MPa for 30 minutes. Conductivity measurement of the membrane permeate and the feed solution was performed using a conductivity measuring device (Kyoto Denshi, CM-117), and from the results and calibration curve (concentration-conductivity), MgSO ₄ The rejection rate was calculated.
Rejection = (1-(MgSO ₄ concentration of MgSO ₄ concentration / feed in the membrane permeate)) × 100 (%)

[Transmission flux]
The permeation flux of the produced composite separation membrane was determined from the amount of membrane permeate measured together with the rejection rate when it was evaluated by the following formula.
Permeation flux (m ³ / (m ² · day)) = permeate volume / (membrane area × sampling time)

Example 1
An aqueous amine solution containing 3.16% by weight of piperazine, 0.04% by weight of m-phenylenediamine (MPD), 0.15% by weight of sodium lauryl sulfate, 0.45% by weight of sodium hydroxide and 6% by weight of camphorsulfonic acid. Then, after applying to a porous polysulfone support membrane (an asymmetric membrane having an average pore size of 20 nm on the side where the separation functional layer is formed and an average pore size different on the opposite side) that is a porous support, an excess aqueous solution was removed. . The ratio of piperazine in the polyfunctional amine contained in the aqueous amine solution was 99.1 mol%, and the ratio of MPD was 0.9 mol%. Next, an isooctane solution containing 0.4% by weight of trimesic acid chloride is brought into contact with the application surface of the aqueous amine solution on the support to advance the interfacial condensation polymerization reaction, and the separation function layer of polyamide ( A composite separation membrane was obtained by forming a thickness of 1 μm.

The composite separation membrane thus obtained had a rejection rate (MgSO ₄ rejection rate) of 99.9% and a permeation flux of 1.69 (m ³ / (m ² · day)).

(Example 2, Comparative Examples 1-3)
A composite separation membrane was produced in the same manner as in Example 1 except that the ratio of piperazine and MPD (monomer charge ratio) in the polyfunctional amine contained in the aqueous amine solution was as shown in Table 1 below. The rejection rate and permeation flux of the obtained composite separation membrane are shown in Table 1 below together with the results of Example 1.

  As shown in Table 1, in Examples 1 and 2, the permeation flux was improved while maintaining the blocking rate as compared with the comparative example.

(Example 3, Comparative Examples 4-6)
Example except that p-phenylenediamine (PPD) was used instead of MPD, and the ratio (monomer charge ratio) of piperazine and PPD in the polyfunctional amine contained in the aqueous amine solution was as shown in Table 2 below. In the same manner as in Example 1, a composite separation membrane was prepared. The rejection rate and permeation flux of the obtained composite separation membrane are shown in Table 2 below.

  As shown in Table 2, in Example 3, the permeation flux was improved while maintaining the blocking rate as compared with the comparative example.

(Examples 4-6, Comparative Examples 7-10)
Except for using PDP as an aromatic polyfunctional amine in addition to MPD, and the ratio of piperazine, MPD and PPD in the polyfunctional amine contained in the aqueous amine solution (monomer charge ratio) as shown in Table 3 below, A composite separation membrane was produced in the same manner as in Example 1. The rejection rate and permeation flux of the obtained composite separation membrane are shown in Table 3 below.

  As shown in Table 3, in Examples 4 to 6, the permeation flux was improved while maintaining the blocking rate as compared with the comparative example.

(Examples 7 and 8, Comparative Examples 11 to 14)
In addition to MPD as an aromatic polyfunctional amine, o-phenylenediamine (OPD) is used, and the ratio (monomer charge ratio) of piperazine, MPD and OPD in the polyfunctional amine contained in the aqueous amine solution is shown in Table 4 below. A composite separation membrane was produced in the same manner as in Example 1 except for the above. The rejection rate and permeation flux of the obtained composite separation membrane are shown in Table 4 below.

  As shown in Table 4, in Examples 7 and 8, the permeation flux was improved while maintaining the salt rejection rate as compared with the comparative example.

(Examples 9 and 10, Comparative Examples 15 to 18)
A composite separation membrane was prepared in the same manner as in Example 1 except that the ratio of piperazine and MPD (monomer charge ratio) in the polyfunctional amine contained in the aqueous amine solution was as shown in Table 5 below. Next, chlorination was carried out by immersing each produced composite separation membrane in an aqueous sodium hypochlorite solution having a free chlorine concentration of 100 mg / L for 72 hours. The rejection rate and permeation flux of the composite separation membrane thus obtained are shown in Table 5 below.

  As shown in Table 5, in Examples 9 and 10, the permeation flux was improved while maintaining the salt rejection rate as compared with the comparative example. Moreover, the value of permeation flux became larger than the case where chlorination was not implemented.

(Examples 11 and 12, Comparative Examples 19 to 23)
Except for using PDP in addition to MPD as an aromatic polyfunctional amine, the ratio of piperazine, MPD and PPD in the polyfunctional amine contained in the aqueous amine solution (monomer charge ratio) is as shown in Table 6 below. A composite separation membrane was produced in the same manner as in Example 1. Next, chlorination was carried out by immersing each produced composite separation membrane in an aqueous sodium hypochlorite solution having a free chlorine concentration of 100 mg / L for 72 hours. The rejection rate and permeation flux of the composite separation membrane thus obtained are shown in Table 6 below.

  As shown in Table 6, in Examples 11 and 12, the permeation flux was improved while maintaining the blocking rate as compared with the comparative example. Moreover, the value of permeation flux became larger than the case where chlorination was not implemented.

(Examples 13 and 14, Comparative Example 24)
Polyvinyl alcohol (degree of saponification 99%) was further added to the aqueous amine solution at a concentration of 0.25 wt%, and the ratios of piperazine and MPD in the polyfunctional amine contained in the aqueous amine solution (monomer charge ratio) are shown in Table 7 below. A composite separation membrane was produced in the same manner as in Example 1 except for the above. The rejection rate and permeation flux of the composite separation membrane thus obtained are shown in Table 7 below.

  As shown in Table 7, in Examples 13 and 14, the permeation flux was improved while maintaining the blocking rate as compared with the comparative example. Further, the value of the permeation flux was larger than when polyvinyl alcohol was not added to the amine aqueous solution.

(Examples 15 and 16, Comparative Example 25)
Polyvinyl alcohol (degree of saponification 99%) was further added to the aqueous amine solution at a concentration of 0.25% by weight, and the ratios of piperazine and MPD in the polyfunctional amine contained in the aqueous amine solution (monomer charge ratio) are shown in Table 8 below. A composite separation membrane was produced in the same manner as in Example 1 except for the above. Next, chlorination was carried out by immersing each produced composite separation membrane in an aqueous sodium hypochlorite solution having a free chlorine concentration of 100 mg / L for 72 hours. The rejection and permeation flux of the composite separation membrane thus obtained are shown in Table 8 below.

  As shown in Table 8, in Examples 15 and 16, the permeation flux was improved while maintaining the salt rejection rate as compared with the comparative example. Moreover, the value of the permeation flux was larger than the case where chlorination was not performed without adding polyvinyl alcohol to the amine aqueous solution.

  The composite separation membrane of this invention can be used for the same use as the conventional composite separation membrane. The application is, for example, use as a reverse osmosis (RO) membrane, ultrafiltration (NF) membrane, microfiltration (MF) membrane, forward osmosis (FO) membrane. More specific applications include, for example, production of pure water or ultrapure water, desalination of brine such as seawater, removal of harmful components or recovery of useful components, concentration or recovery of active ingredients in the food or pharmaceutical field. It can be used for advanced processing.

30 Laminate 31 Composite Separation Membrane 32 Supply Side Channel Material 33 Permeation Side Channel Material 35

Claims (8)

A porous support, and a separation functional layer formed on the porous support,
The separation functional layer is composed of a polyamide formed by a reaction of a compound group including an aromatic polyfunctional amine, an aliphatic polyfunctional amine, and a polyfunctional acid halide,
In the compound group, a composite separation membrane in which a ratio of the aromatic polyfunctional amine to a polyfunctional amine is 1 mol% or more and 4 mol% or less .   The composite separation membrane according to claim 1, wherein the aliphatic polyfunctional amine is an alicyclic polyfunctional amine.   The composite separation membrane according to claim 1, wherein the aliphatic polyfunctional amine is piperazine or a piperazine derivative.   The aromatic polyfunctional amine is m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene, 3,5-diaminobenzoic acid. 2,4-diaminotoluene, 2,6-diaminotoluene, N, N′-dimethyl-m-phenylenediamine, 2,4-diaminoanisole, amidole, and xylylenediamine, Item 4. The composite separation membrane according to any one of Items 1 to 3.   The composite separation membrane according to any one of claims 1 to 3, wherein the aromatic polyfunctional amine is at least one selected from m-phenylenediamine, p-phenylenediamine, and o-phenylenediamine.   The composite separation membrane according to any one of claims 1 to 5, wherein the compound group further comprises a hydrophilic polymer.   The composite separation membrane according to claim 6, wherein the hydrophilic polymer is polyvinyl alcohol. Separation membrane element using a composite separation membrane according to any one of claims 1-7.

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