KR20190136289A - Pressure retarded osmosis membrane having excellent water permeability and anti-fouling and pressure retarded osmosis module comprising the same - Google Patents

Abstract

The present invention relates to a pressure delayed osmosis membrane having excellent water permeability and pollution resistance, a pressure delayed osmosis membrane including the same, and a pressure delayed osmosis module including the same. More specifically, the present invention relates to a pressure delayed osmosis membrane capable of minimizing the power density reduction due to organic fouling under high pressure operating conditions, such as SWRO-PRO combination processes and reducing replacement cycles of membranes and modules as well as the costs of CIP cleaning. The present invention also relates to a pressure delay osmosis module including the same.

Description

Pressure retarded osmosis membrane having excellent water permeability and anti-fouling and pressure retarded osmosis module comprising the same}

The present invention relates to a pressure delayed osmosis membrane having excellent water permeability and fouling resistance, a pressure delayed osmosis membrane including the same, and a pressure delayed osmosis module including the same, and more particularly, to organic materials under high pressure operating conditions such as a SWRO-PRO combination process. The present invention relates to a pressure delayed osmosis module including a same and a pressure delayed osmosis membrane capable of minimizing a decrease in power density due to fouling, a replacement cycle of a separator and a module, and a CIP cleaning cost.

Pressure retarded osmosis (PRO) is a phenomenon in which water moves through osmosis between high and low salt solutions with different salt gradients through semipermeable membranes. In detail, the salinity difference delays the osmotic water flow by applying a pressure lower than the osmotic pressure in the opposite direction of the osmotic phenomenon generated through the membrane in another solution, so that the water transmitted through the membrane rotates the turbine to produce electricity.

This osmosis power generation technology is a renewable energy field that can be applied to the border area where seawater and freshwater meet. Especially, the osmotic power plant can provide a continuous source of electricity under any weather conditions unlike wind, wave and solar energy. The value is endless.

SWRO-PRO (Sea Water Retarded Osmosis -Pressure Retarded Osmosis) combination process to improve the energy efficiency of osmotic power generation uses high concentration of SWRO concentrated water as draw solution and low concentration sewage effluent as feed solution. Can be. In other words, the greater the salinity gradient, the greater the osmotic pressure and high efficiency of energy production. However, the prior art is only a report on the equipment and maintenance using pressure delay osmosis, the research report on a suitable dedicated membrane of the pressure delay osmosis power generation is insufficient.

Therefore, the osmotic pressure is increased in the SWRO-PRO combination process, it is necessary to develop a pressure-resistant and high-efficiency PRO membrane and module suitable for high pressure operating conditions.

In addition, when the sewage effluent is applied as a feed solution, a fouling (fourling) phenomenon occurs on the back side of the separator, and thus a method for preventing the situation is required.

Korea Patent Registration No. 10-1268936

The present invention has been made in view of the above, it is possible to minimize the power density degradation due to organic fouling under high pressure operating conditions, such as SWRO-PRO combination process, replacement cycle of membrane and module, CIP cleaning cost An object of the present invention is to provide a pressure delayed osmosis membrane module having excellent water permeability and pollution resistance and a pressure delayed osmosis membrane module including the same.

In order to solve the above problems, the present invention comprises the steps of (1) preparing a polymer solution by mixing an anionic compound, a polymer and a solvent, (2) on the porous support layer to penetrate into the pores of the porous support layer Forming a polymer support layer on the porous support layer by phase-transferring the polymer solution after treating the polymer solution, and (3) forming a hydrophilic selective layer on the polymer support layer, wherein the anionic compound And the polymer provides a method for producing a pressure delayed osmosis membrane is mixed in a weight ratio of 1:18 to 15: 4.

According to one embodiment of the present invention, the polymer solution may satisfy the following Equation 1.

[Relationship 1]

In Formula 1, A is the content of the anionic compound in the polymer solution (% by weight), and B is the viscosity (cps) of the polymer solution.

In addition, according to an embodiment of the present invention, the anionic compound may be at least one selected from polyacrylic acid, polystyrene, sulfonated polysulfone, and cellulose.

In addition, according to a preferred embodiment of the present invention, the anionic compound is polyacrylic acid, polystyrene sulfonate, sulfonated polysulfone, carboxymethyl cellulose and cellulose It may be at least one selected from cellulose sulfate.

In addition, according to an embodiment of the present invention, the polymer is a polysulfone-based, polyamide-based, polyimide-based, polyester-based, polypropylene-based, polyethylene-based, polybenzoimidazole-based, polyvinylidenedifluoride-based And it may be at least any one selected from polyacrylic.

In addition, according to one embodiment of the present invention, the porous support layer may be composed of at least one fiber selected from polyester, polypropylene, nylon, polyethylene, acrylic, rayon, acetate and cellulose.

In addition, according to an embodiment of the present invention, the hydrophilic selection layer may include any one or more selected from polyamide-based, polypiperazine-based, polyphenylenediamine-based, polychlorophenylenediamine-based and polybenzidine-based have.

In addition, the present invention provides a porous support layer, a polymer support layer formed on the porous support layer, containing an anionic compound and a polymer in a weight ratio of 1:18 to 15: 4 and a hydrophilic selective layer formed on the polymer support layer It provides a pressure delay osmosis membrane comprising.

According to a preferred embodiment of the present invention, the anionic compound and the polymer may be included in a weight ratio of 2:17 to 10: 9.

In addition, according to an embodiment of the present invention, the rear surface of the pressure delayed osmosis membrane may have a zeta potential potential of 25 to −70 mV at a pH of 5 to 10.

In addition, according to an embodiment of the present invention, the rear surface of the pressure delayed osmosis membrane may have a zeta potential potential of −35 to −70 mV at a pH of 8 to 10.

In addition, according to one embodiment of the present invention, the pressure delayed osmosis membrane has a pressure of 25 ° C., 20 bar, a flow rate of 0.5 LPM, and a pH 6 condition of 70000 ppm sodium chloride aqueous solution as an induction solution and 100 ppm sodium alginate as a feed solution. The PRO reduction rate represented by the following Equation 2 may be 25% or less.

[Calculation 2]

In Formula 2, W ₁ is the power density of the initial pressure delayed osmosis membrane, W ₂ is the power density of the pressure delayed osmosis membrane after operating for 2 hours.

In addition, the present invention provides a pressure delay osmosis module having a pressure delay osmosis membrane according to the present invention.

The pressure delayed osmosis membrane according to the present invention has excellent water permeability and pollution resistance, thereby minimizing power density degradation due to organic fouling under high pressure operating conditions, and is widely used in the SWRO-PRO combination process by being included in the pressure delayed osmosis module. Reduce cycles for membrane and module replacement and CIP cleaning.

1 is a cross-sectional view of a pressure delayed osmosis membrane according to an embodiment of the present invention.
Figure 2 is a schematic diagram showing the cross-sectional view of the membrane used in the RO and PRO process and fouling phenomenon.
Figure 3 is a schematic diagram of the pressure delay osmosis membrane module according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

As shown in FIG. 2, unlike the reverse osmosis (RO) and forward osmosis (FO) processes, the PRO process has an active layer or an active layer at the backing layer of the membrane depending on the osmotic gradient. There is a problem that the fouling phenomenon occurs to the back side of the separation membrane to move to the selection layer. Such fouling causes a deterioration of the membrane and shortens the membrane module replacement and CIP cleaning cycle, thereby increasing the maintenance cost of the process.

In order to prevent the above-described problems, as shown in FIG. 1, the pressure-delayed osmosis membrane 10 of the present invention includes an anionic compound in the polymer support layer 12 to impart a negative charge to the back surface 14 of the separator and fouling. The phenomenon can be prevented or minimized.

Hereinafter, a method of manufacturing a pressure delayed osmotic membrane according to the present invention will be described.

First, as step (1), an anionic compound, a polymer, and a solvent are mixed to prepare a polymer solution.

The anionic compound may be a hydrophilic material capable of improving the water permeability of the pressure-delayed osmotic membrane, preferably at least one selected from polyacrylic acid, polystyrene, sulfonated polysulfone, and cellulose, and more preferably. It may be at least one selected from polyacrylic acid, polystyrene sulfonate, sulfonated poysulfone, carboxymethyl cellulose, and cellulose sulfate.

The term "polyacrylic acid type" in the present invention means a polymer containing acrylic acid or a salt thereof as a main component as a repeating unit. The term "polystyrene-based" in the present invention means a polymer containing styrene or a salt thereof as a main component as a repeating unit. The term "sulfonated polysulfone system" in the present invention means a polymer containing sulfonated polysulfone or a salt thereof as a main component as a repeating unit. "Cellulose-based" in the present invention means a polymer containing cellulose or a salt thereof as a main component as a repeating unit.

The polymer is used as a polymer support layer of the pressure-delayed osmotic membrane, polysulfone, polyamide, polyimide, polyester, polypropylene, polyethylene, polybenzoimidazole, polyvinylidenedifluoride and poly At least any one selected from the group consisting of acryl-based polymers, preferably polysulfone, polyethersulfone, polypropylene, polyethylene, polybenzoimidazole, polyvinylidene difluoride, and polyacrylonitrile It may include.

The solvent may be used without limitation as long as it is a conventional organic solvent capable of dissolving a material used as a polymer support layer known in the art. For example, dimethylformamide (DMF), dimethylacetamide, dimethyl sulfoxide and N- It may be any one selected from methyl-2-pyrrolidone (NMP) or a combination thereof.

The anionic compound and the polymer may be mixed in a weight ratio of 1:18 to 15: 4, and if the weight ratio is less than 1:18, the negative charge imparted to the back surface 14 of the pressure delayed osmosis membrane 10 Is not implemented at the desired level, organic fouling may occur on the back surface 14 of the pressure-delayed osmotic membrane 10 when using a feed solution such as sewage effluent, which may cause a problem that the water permeability and power density of the membrane are reduced. have. In addition, when the weight ratio exceeds 15: 4, the viscosity of the polymer solution is lowered, so that the back-off property is increased, and the thickness of the polymer support layer is not uniformly formed, thereby achieving the object of the present invention. It can be difficult.

Preferably, the anionic compound and the polymer may be mixed in a weight ratio of 2:17 to 10: 9, more preferably 3:16 to 7:12, and the anionic compound and the polymer may be 2:17 to When mixed at a weight ratio of 10: 9, the pressure reduction rate of the prepared pressure delayed osmosis membrane may be excellent, and thus the PRO reduction rate may be lowered. When the anionic compound and the polymer are mixed at the weight ratio of 3:17 to 7: 9, The pressure delayed osmotic membrane to be prepared may have excellent stain resistance and high water permeability at the same time.

In addition, according to one embodiment of the present invention, the polymer solution may satisfy the following Equation 1.

[Relationship 1]

In Formula 1, A is the content of the anionic compound in the polymer solution (% by weight), and B is the viscosity (cps) of the polymer solution.

The viscosity of the polymer solution affects the film forming property of the separator, and in order to realize excellent water permeability, fouling resistance and film forming property, it is preferable to satisfy the above Equation 1.

When the B / A value is less than 10, the viscosity of the polymer solution is lowered, so that the back side detachment property of the polymer solution is increased in step (2), which will be described later. And it may be difficult to achieve the object of the present invention, such as lowering the power density.

In addition, when the B / A value exceeds 3000, the negative charge imparted to the back surface 14 of the pressure delayed osmosis membrane 10 may not be realized at a desired level, and in the phase transition process for solidification of the polymer solution. It may be difficult to achieve the object of the present invention, such as the polymer support layer being detached from the porous support layer.

Preferably, the B / A value may be 20 to 1500, more preferably 28 to 1000, and when the B / A value is 20 to 1500, the pressure reduction rate of the pressure delayed osmosis membrane to be prepared may be lowered. When the B / A value is 28 to 1000, the pressure delayed osmosis membrane may be prepared at the same time having excellent stain resistance and high water permeability.

The anionic compound, the polymer, and the solvent may be mixed by a mixing method known in the art to form a polymer solution, for example, a stirring method or an ultrasonic treatment method may be used, but is not limited thereto.

In addition, according to one embodiment of the present invention, the thickness of the polymer support layer 12 may be 30 ~ 250 ㎛, but is not limited thereto. If the thickness is less than 30 μm, the pressure resistance and / or contamination resistance of the entire membrane may be lowered, and if it exceeds 250 μm, the water permeability may be lowered.

Next, in step (2), the polymer solution is treated on the porous support layer to infiltrate the pores of the porous support layer into the pores of the porous support layer, and then the phase of the polymer solution is transferred to the porous support layer. A polymeric support layer is formed on it.

The polymer solution may impart a negative charge to the back surface of the pressure delayed osmosis membrane prepared by penetrating into the pores of the porous support layer, and when the polymer solution is phase-transferred to form a polymer support layer, bond strength between the polymer support layer and the porous support layer Reinforcement helps to prevent the polymer support layer from detaching from the porous support layer.

In order to be used in the SWRO-PRO combination process operating under high pressure conditions, the porous support layer is preferably made of a material having pressure resistance, hydrophilicity and excellent porosity.

The porous support layer 11 may be a known material that can be used in the pressure delayed osmotic membrane in the art, preferably at least any one selected from nylon, polyester, polypropylene, polyethylene, acrylic, rayon, acetate and cellulose It may be a material composed of one fiber.

According to a preferred embodiment of the present invention, the porous support layer 11 includes a weft and a warp, and may satisfy the following conditions.

(A) 250-400 number of intersections (carpenters) of weft and warp in 1 in ² area

(B) 100 ~ 650 cc / cm ² · sec of the air permeability

When the carpenter is less than 250, the tensile strength of the porous support layer 11 is significantly lowered, such that the pressure delay osmosis membrane itself may be damaged under high pressure operating conditions, and if more than 400, Although the strength may be excellent, the water permeability and power density of the separator may be significantly reduced. Therefore, when the above conditions are satisfied, there is an advantage that can simultaneously have excellent mechanical stability and water permeability even under high pressure operating conditions such as SWRO-PRO mixing process.

The weft and warp yarns can be used without limitation as long as they can be used in the material of the pressure-delay osmotic membrane, respectively, preferably at least one fiber selected from the group consisting of nylon, polyester, polypropylene, polyethylene, acrylic and cellulose It may include, the cellulose may be, for example, rayon and / or acetate and the like.

The thickness of the porous support layer 11 may affect the mechanical strength of the fabric and the pressure delayed osmosis membrane including the carpenter and the fineness of the fabric. Accordingly, the thickness of the porous support layer of the present invention is 40 to 100 μm. It may be preferably from 45 to 80 ㎛ to obtain better mechanical strength, flow rate, power density. If the thickness is less than 40 μm, the tensile strength of the support layer may be remarkably lowered, thereby lowering the mechanical strength of the pressure-delayed osmotic membrane including the same, and thus, the membrane surface may be damaged by the pressure applied during operation. And, the damage of such a film may have a problem that can lower the power density, flow rate.

In addition, if the thickness exceeds 100㎛ mechanical strength can be improved, but the flow rate and power density is significantly reduced, the pressure delay osmosis contained in the limited volume by increasing the thickness of the pressure delay osmosis membrane itself including the same There may be a problem in that the content of the membrane, specifically the osmotic gradient, can be formed to further reduce the flow rate and power density obtained by reducing the effective area.

The treatment method of the polymer solution may be used without limitation the treatment method of the polymer solution that can be commonly used in the art, for example, dipping (spraying), drop casting (drop casting), self-assembly, spin Spin coating, doctor blade, bar coating, slot die coating, microgravure coating, coma coating and printing, It may be any one method selected from a casting method, preferably a casting method.

As the method for phase transition, a known phase transition method commonly used in the art may be used. For example, a support layer on which a polymer solution is treated is immersed in a coagulation bath including a non-solvent to form a polymer support layer on the support layer. You can.

The non-solvent is intended to exchange the phase change with the solvent of the polymer solution, as long as it is a non-solvent used in the phase transition process in the art, it may be used without limitation, for example, water, dimethylformamide, ethanol or a combination thereof.

The temperature of the coagulation bath is not particularly limited as long as it is a temperature normally used in a phase change process in the art, preferably 10 to 30 ° C.

Next, as a step (3), a hydrophilic selective layer 13 is formed on the polymer support layer.

The hydrophilic selective layer 13 may be prepared using an active layer production method of a pressure delayed osmotic membrane known in the art, for example, may be an interfacial polymerization method, but is not limited thereto.

The hydrophilic selective layer 13 may be formed of a dense surface layer to form a structure having excellent mechanical stability under high pressure conditions, and at the same time, the thin hydrophilic selective layer may maintain excellent porosity by maintaining pores of uniform size.

The material of the hydrophilic selective layer 13 may be used without limitation the material used as the active layer of the pressure delayed osmotic membrane in the art, preferably polyamide polymer, poly piperazine polymer, polyphenylenediamine polymer, It may include at least one polymer selected from polychlorophenylenediamine-based polymer and polybenzidine-based polymer, more preferably may include a polyamide-based polymer.

When the hydrophilic selective layer 13 is a layer made of a polyamide-based polymer, the polyamide layer is formed by alkylation with a polyfunctional amine selected from metaphenyldiamine, paraphenyldiamine, orthophenyldiamine, piperazine or alkylated peperidine. The aqueous solution containing the aliphatic amine can be brought into contact with an organic solution containing a polyfunctional acid halide compound selected from polyfunctional acyl halide, polyfunctional sulfonyl halide or polyfunctional isocyanate and interfacial polymerization between the compounds. Hydrophilic having at least one hydrophilic functional group selected from the group consisting of hydroxy group, sulfonated group, carbonyl group, trialkoxysilane group, anionic group and tertiary amino group in the aqueous solution containing polyfunctional amine-containing or alkylated aliphatic amine Compounds, ie hydrophilic amino compounds, may be further added.

The hydrophilic compound having the hydroxy group is selected from 1,3-diamino-2-propanol, ethanolamine, diethanolamine, 3-amino-1-propanol, 4-amino-1-butanol and 2-amino-1-butanol Can be selected.

The hydrophilic compound having a carbonyl group is selected from the group consisting of aminoacetaldehyde dimethylacetal, α-aminobutylolactone, 3-aminobenzamide, 4-aminobenzamide and N- (3-aminopropyl) -2-pyrrolidinone Can be.

In addition, the hydrophilic compound containing a trialkoxysilane group may be selected from (3-aminopropyl) triethoxysilane or (3-aminopropyl) trimethoxysilane.

Examples of the hydrophilic compound having an anion group include glycine, taurine, 3-amino-1-propenesulphonic acid, 4-amino-1-butenesulphonic acid, 2-aminoethylhydrogensulfate, 3-aminobenzenesulfonic acid, 3-amino-4-hydroxybenzenesulphonic acid, 4-aminobenzenesulphonic acid, 3-aminopropylphosphonic acid, 3-amino-4-hydroxybenzoic acid, 4-amino-3-hydroxybenzoic acid It can be selected from the group consisting of Ixex, 6-aminohexene oixex, 3-aminobutan ooxyex, 4-amino-2-hydroxybutyric acid, 4-aminobutyric acid and glutamic acid.

In addition, hydrophilic compounds having one or more tertiary amino groups include 3- (dimethylamino) propylamine, 3- (diethylamino) propylamine, 4- (2-aminoethyl) morpholine, 1- (2- Aminoethyl) piperazine, 3,3'-diamino-N-methyldipropylamine and 1- (3-aminopropyl) imidazole.

Next, the pressure delayed osmosis membrane 10 according to the present invention will be described.

The pressure delayed osmosis membrane includes a support layer 11, a polymer support layer 12 formed on the support layer 11, and a hydrophilic selective layer 13 formed on the polymer support layer 12.

The back surface 14 of the pressure delayed osmosis membrane 10 may have a zeta potential potential value of 25 to −70 mV at a pH of 5 to 10. If the zeta potential potential value of the back surface 14 exceeds -25 mV, the negative charge imparted to the back surface of the polymer support layer may not be expressed at a desired level, and thus, the fouling resistance of the pressure delayed osmosis membrane may be lowered. Therefore, it may be difficult to achieve the object of the present invention, such as increasing the PRO reduction rate. In addition, in order to achieve the zeta potential potential value of less than -70 mV, an excessive amount of anionic compound must be included in the polymer support layer. Accordingly, when the polymer support layer is manufactured, the viscosity of the polymer solution is decreased, so that the backing property is increased, and the polymer support layer is increased. Since the thickness is not formed uniformly, the film forming property may be degraded, and thus it may be difficult to manufacture the separator itself.

In addition, the back surface 14 of the pressure delayed osmosis membrane 10 according to the present invention may have a zeta potential potential value of −35 to −70 mV at a pH of 8 to 10, and thus may have excellent fouling resistance even under basic conditions. have.

If the zeta potential potential value of the back surface 14 exceeds -35 mV, the negative charge imparted to the back surface of the polymer support layer may not be expressed at a desired level, and thus, the fouling resistance of the pressure delayed osmosis membrane may be degraded under basic conditions. And, accordingly, it may be difficult to achieve the object of the present invention, such as increasing the PRO reduction rate. In addition, in order to achieve the zeta potential potential value of less than -70 mV, an excessive amount of anionic compound must be included in the polymer support layer. Accordingly, when the polymer support layer is manufactured, the viscosity of the polymer solution is decreased, so that the backing property is increased, and the polymer support layer is increased. Since the thickness is not formed uniformly, the film forming property may be degraded, and thus it may be difficult to manufacture the separator itself.

As described above, the pressure-delayed osmotic membrane of the present invention has excellent hydrophilicity and pressure resistance and excellent organic fouling inhibiting effect, and thus may have excellent water permeability, power density, and fouling resistance under the conditions described below.

 In addition, the pressure-delayed osmotic membrane according to an embodiment of the present invention may have excellent stain resistance at high pressure operating conditions, specifically, 25 ° C for 70000 ppm sodium chloride aqueous solution as an induction solution and 100 ppm sodium alginate as a feed solution, Under a pressure of 20 bar, a flow rate of 0.5 LPM, and pH 6 conditions, the PRO reduction rate represented by the following Equation 2 may be 25% or less.

[Calculation 2]

In Formula 2, W ₁ is the power density of the initial pressure delayed osmosis membrane, W ₂ is the power density of the pressure delayed osmosis membrane after operating for 2 hours.

On the other hand, the present invention provides a pressure delay osmosis module comprising the pressure delay osmosis membrane of the present invention.

Specifically, the non-woven fabric of the present invention or the pressure-delayed osmotic membrane of the present invention comprising the nonwoven fabric is preferably wound in a spiral wound in a porous permeate outflow pipe and included in the module, and wound in a spiral wound type by being wound in a spiral wound type. The surface area of the pressure-delayed osmotic membrane included per unit volume of the module can be made wider, and thus an effective area capable of osmotic action is increased, so that an osmotic pressure gradient is well formed.

More specifically, FIG. 3 is an exploded perspective view of a pressure case in which a preferred embodiment of the present invention is wound and wound in a spiral wound type, and a plurality of pressure delayed osmosis membrane assemblies in a pressure delay osmosis module according to a preferred embodiment of the present invention. The porous permeate outflow pipe 20 including the plurality of holes 21 may be wound in a spiral wound around the pressure case 30. Alternatively, the pressure-delayed osmosis membrane 22 wound as described above may be wrapped using a fiber reinforced plastics (FRP, etc.) rather than an outer case.

The pressure case 30 may determine the size and shape so as to accommodate the pressure delay osmosis module located therein, and preferably the shape of the pressure case 30 is wound into a plurality of pressure delay osmosis membranes or windings. However, it is not limited to the said description. In the case of the material of the case may be used without limitation in the case of a pressure case material that is typically used in the pressure delay osmosis method.

Example 1

As a support layer, a carpenter prepares a woven fabric of 250 to 400 plain weaves in the area of width (2.54 cm) x length (2.54 cm) of polyester weft and warp yarns. The fabric has an air permeability within the range of 100 to 650 cc / cm ² · sec, with a thickness of 70 ± 5 μm.

Polyacrylic acid and polysulfone were added to a solvent in which dimethylformamide and N-methyl-2-pyrrolidone were mixed at a weight ratio of 1.2: 17.8 to prepare a polymer solution including 19 wt% of a polymer. The viscosity of the prepared polymer solution was 1000 cps.

The polymer solution was applied to one side of the fabric with a thickness of 50 μm, and immersed in a coagulation bath containing 1 wt% of dimethylformamide (DMF) in non-solvent water to form a polymer support layer through phase transition. At this time, the temperature of the coagulation bath solution was maintained at 20 ℃.

The sample in which the polymer support layer was formed on the porous support layer was used for the zeta potential measurement, and the difference in the zeta potential potential values on the back surface and the surface of the separator was 10% or less.

The polymer support layer was immersed in an aqueous solution containing 3.5% by weight of metaphenylenediamine (MPD) for 1 minute, and then the water layer on the surface was removed by a compression method. Subsequently, the mixture was immersed in an organic solution containing 0.1% by weight of trimezoyl chloride (TMC) in an ISOPAR solvent (Exxon Corp.) for 1 minute, followed by interfacial polymerization, followed by natural drying at room temperature (25 ° C) for 1 minute and 30 seconds to form polyamide. The constructed hydrophilic selective layer was formed. Thereafter, to remove unreacted residues, a pressure-delayed osmotic membrane having a total thickness of 110 ± 10 μm was prepared by immersion in 0.2 wt% sodium carbonate solution for 2 hours.

(Examples 2-7)

The same procedure as in Example 1 was performed, but as shown in Table 1, a pressure delayed osmotic membrane including a polymer support layer formed by varying the weight ratio of polyacrylic acid and polysulfone was prepared.

Example 8

In the same manner as in Example 1, the polymer solution was prepared by adding sulfonated polysulfone and polysulfone to a solvent in which dimethylformamide and N-methyl-2-pyrrolidone were mixed in a weight ratio of 1.2: 17.8.

(Examples 9-11)

As in Example 1, but as shown in Table 1 to prepare a pressure-delayed osmotic membrane comprising a polymer support layer formed by varying the weight ratio of sulfonated polysulfone and polysulfone.

(Comparative Example 1)

A pressure delayed osmosis membrane was prepared in the same manner as in Example 1 but including a polymer support layer formed using a polymer solution containing only polysulfone.

(Comparative Example 2)

In the same manner as in Example 1, a pressure-delayed osmotic membrane including a polymer support layer was formed using a polymer solution containing polyacrylic acid and polysulfone in a weight ratio of 0.7: 18.3.

(Comparative Example 3)

In the same manner as in Example 1, a pressure-delayed osmotic membrane including a polymer support layer formed using a polymer solution containing polyacrylic acid and polysulfone in a weight ratio of 16: 3 was prepared.

(Comparative Example 4)

In the same manner as in Example 8, a pressure-delayed osmotic membrane including a polymer support layer formed by using a polymer solution containing sulfonated polysulfone and polysulfone at a weight ratio of 0.7: 18.3 was prepared.

(Comparative Example 5)

In the same manner as in Example 8, a pressure-delayed osmotic membrane including a polymer support layer formed using a polymer solution containing sulfonated polysulfone and polysulfone in a weight ratio of 16: 3 was prepared.

(Comparative Example 6)

In the same manner as in Example 1, a pressure-delayed osmotic membrane including a polymer support layer formed using a polymer solution containing polyvinylpyrrolidone-based polymer and polysulfone in a weight ratio of 3:16 was prepared.

Experimental Example 1 Zeta Potential Measurement

The polymer solution prepared in Examples 1 to 7 and Comparative Examples 1 to 4 was treated with a zeta potential measuring device (Surpass Electrokinetic Analyzer, Anton-Paar) and transferred to the porous support layer to prepare a polymer support layer formed on the porous support layer. Zeta potential potential on the back side was measured under the condition of pH 6.

Experimental Example 2 Water Permeability Measurement

The hydrophilic selective layer of the pressure delayed osmosis membranes prepared in Examples 1 to 7 and Comparative Examples 1 to 4 was mounted in the direction facing the induction solution (sodium chloride solution) and 70,000 as the induction solution at a pressure of 20 bar. The water permeability [gfd] (gallon / feet ² · day) of the pressure delayed osmosis membrane was measured using distilled water as the aqueous solution of ppm sodium chloride and feed solution. Table 1 shows the results of water permeability measurement.

(Example 3) Calculation of power density and PRO reduction rate

In order to confirm the effect of inhibiting organic fouling, the pressure-delayed osmosis membranes prepared in Examples 1 to 7 and Comparative Examples 1 to 4 were subjected to 70,000 ppm aqueous sodium chloride solution and 100 ppm sodium alginate (sodium) as a feed solution under a pressurized condition of 20 bar. alginate) was used for 2 hours at 25 ° C. and pH 6, and the water permeability and initial water permeability of the pressure delayed osmosis membrane were measured, and the power density was calculated by the following Equation 1.

[Calculation 1]

In Formula 1, W is power density, JW is flow rate, and ΔP is pressure.

In addition, the PRO reduction rate was calculated from the power density (W2) and the initial power density (W1) after the operation through the following equation (2).

[Calculation 2]

In Formula 2, W ₁ is the power density of the initial pressure delayed osmosis membrane, W ₂ is the power density of the pressure delayed osmosis membrane after operating for 2 hours.

Calculated power density and PRO reduction rate of the pressure delayed osmosis membrane are shown in Table 1 below.

division Composition of Polymer Support Layer Zeta Potential Behind Polymer Support Layer
Potential value (mV) Initial pressure delay
Osmosis Membrane Properties Properties of Pressure Delay Osmosis Membrane after 2 Hours of Fouling Operation PRO power density
Reduction
(%) pH 6 pH 9 Water permeability
(GFD) Power density
(W1) Water permeability
(GFD) power
density
(W2) Comparative Example 1 PA: PS = 0: 19 1.91 -13.34 2.10 1.97 1.15 1.08 45.2 Comparative Example 2 PA: PS = 0.7: 18.3 -7.12 -30.29 4.38 4.12 2.98 2.80 32.0 Example 1 PA: PS = 1.2: 17.8 -27.31 -36.90 7.61 7.15 5.77 5.42 24.2 Example 2 PA: PS = 1.8: 17.2 -39.16 -49.14 7.87 7.40 6.27 5.89 20.3 Example 3 PA: PS = 2.5: 16.5 -46.44 -52.75 8.23 7.74 6.93 6.51 15.8 Example 4 PA: PS = 3.5: 14 -52.82 -55.87 10.21 9.60 8.79 8.26 13.9 Example 5 PA: PS = 6: 9 -54.28 -61.45 10.32 9.70 9.05 8.51 12.3 Example 6 PA: PS = 8: 6 -54.81 -62.35 10.55 9.92 9.10 8.55 13.7 Example 7 PA: PS = 14.5: 4.5 -55.27 -63.12 10.50 9.87 8.86 8.33 15.6 Comparative Example 3 PA: PS = 16: 3 -55.52 -64.20 9.34 8.78 7.35 6.91 21.3 Comparative Example 4 SPsf: PS = 0.7: 18.3 -10.50 -33.30 5.63 5.29 4.01 3.77 28.8 Example 8 SPsf: PS = 1.2: 17.8 -37.20 -42.73 9.23 8.68 7.30 6.86 20.9 Example 9 SPsf: PS = 3: 16 -50.11 -55.35 11.53 10.84 9.98 9.38 13.4 Example
10 SPsf: PS = 5: 14 -53.39 -60.81 13.15 12.36 11.64 10.94 11.5 Example
11 SPsf: PS = 14.5: 4.5 -55.83 -64.22 11.79 11.08 9.53 8.96 19.2 Comparative Example 5 SPsf: PS = 16: 3 -55.75 -66.44 10.55 9.92 8.31 7.81 21.2 Comparative Example 6 PVP: PS = 3: 16 -16.00 -33.82 6.30 5.92 4.52 4.25 28.3 * PA: polyacrylic acid, PS: polysulfone, SPsf: sulfonated polysulfone, PVP: polyvinylpyrrolidone-based polymer

Table 1 will be described in detail.

Comparative Example 1 is a pressure delayed osmosis membrane in which the polymer support layer is composed of only polysulfone. Zeta potential potential value of the polymer support layer of Comparative Example 1 is a positive value of 1.91 mV, it can be expected that the organic fouling with a negative charge cannot be suppressed. In addition, Comparative Example 1 does not include an anionic compound exhibiting hydrophilicity, so the water permeability and power density are significantly lower than those of Examples 1 to 7 including an anionic compound, and the PRO reduction rate is 45.2%. It can be seen that it occurred.

Comparative Example 6 is a pressure-delayed osmotic membrane comprising a polyvinylpyrrolidone-based polymer in the polymer support layer, wherein the polymer support layer of Comparative Example 6 contains nonionic PVP in the same weight ratio (3:19) as SPsf of Example 9 However, since the zeta potential potential value is significantly higher than that of Example 9 including SPsf, that is, the anionicity is low, it is judged that the expected value of the organic fouling inhibitory effect cannot be expected.

Next, Comparative Example 2 containing an anionic compound (PA) has a lower zeta potential potential value and slightly increased water permeability and power density than Comparative Example 1 containing no anionic compound, but the PRO reduction rate was 32.0%. It can be seen that the pollution resistance is relatively lower than Examples 1 to 7.

In the case of Example 1, although the PA content was slightly increased based on Comparative Example 1, the PRO reduction rate was 24.2%, which was significantly lower than that of Comparative Example 1, when the zeta potential potential on the back side of the polymer support layer was -25 mV or less. The fouling inhibitory effect is considered to be significantly higher.

When the content of PA is gradually increased, it can be seen that the zeta potential potential value gradually decreases on the back surface of the polymer support layer. Examples 2 to 6 show a low PRO reduction rate of 25% or less. In particular, Examples 4 to 6 showed a PRO reduction rate of 15% or less, and the lowest PRO reduction rate of Example 5 in which the weight ratio of the anionic compound (PA) and the polymer (PS) was 6: 9 was confirmed to be the lowest. It was. When the content of PA is increased, the zeta potential potential value on the back side of the polymer support layer may be reduced, but when the weight ratio of the anionic compound (PA) and the polymer (PS) is 14.5: 4.5 (Example 7), anionic The PRO reduction rate was higher than that of the pressure delayed permeable membrane in which the weight ratio of the compound (PA) and the polymer (PS) was 8: 6 (Example 6). That is, when the content of the anionic compound is excessively increased, the PRO reduction rate may increase.

In addition, when using sulfonated polysulfone (SPsf) as an anionic compound included in the polymer support layer, the weight ratio of SPsf: PS is 0.7: 18.3 than the comparative example 4 of the SPsf: PS weight ratio of 0.7: 18.3 It can be seen that the PRO reduction rate of 8 is significantly low.

Comparative Example 5 in which the weight ratio of SPsf: PS is 16: 3 can be confirmed that the PRO reduction ratio is higher than that in Example 11 in which the weight ratio of SPsf: PS is 14.5: 4.5. That is, when the content of the anionic compound is excessively increased, the PRO reduction rate may increase. In Example 9 and Example 10, the PRO reduction rate was 15% or less, and the PRO reduction rate of Example 10 was 11.5%, which was the lowest.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments set forth herein, and those skilled in the art who understand the spirit of the present invention, within the scope of the same idea, the addition of components Other embodiments may be easily proposed by changing, deleting, adding, and the like, but this will also fall within the spirit of the present invention.

10: pressure delay osmosis membrane
11: support layer
12: polymer support layer
13: hydrophilic selection layer
14: back side
20: porous permeate outflow pipe
21: Hall
22: pressure delay osmosis membrane
30: pressure case

Claims (13)

(1) mixing an anionic compound, a polymer, and a solvent to prepare a polymer solution;
(2) treating the polymer solution on the porous support layer so that the polymer solution penetrates into pores of the porous support layer and then phase shifts the polymer solution to form a polymer support layer on the porous support layer; And
(3) forming a hydrophilic selective layer on the polymer support layer:
Including,
The anionic compound and the polymer is a method of producing a pressure delayed osmosis membrane is mixed in a weight ratio of 1:18 to 15: 4.
The method of claim 1,
The polymer solution is a method of producing a pressure delayed osmosis membrane that satisfies the following relation:
[Relationship 1]

In Formula 1, A is the content of the anionic compound in the polymer solution (% by weight), and B is the viscosity (cps) of the polymer solution. The method of claim 1,
The anionic compound is at least any one selected from polyacrylic acid, polystyrene, sulfonated polysulfone, and cellulose.
The method of claim 1,
The anionic compound is at least one selected from polyacrylic acid, polystyrene sulfonate, sulfonated polysulfone, carboxymethyl cellulose, and cellulose sulfate. Method for producing a delayed osmosis membrane.
The method of claim 1,
The polymer is at least one selected from polysulfone, polyamide, polyimide, polyester, polypropylene, polyethylene, polybenzoimidazole, polyvinylidene difluoride and polyacryl. Method for producing an osmosis membrane.
The method of claim 1,
The porous support layer is a method for producing a pressure-delayed osmotic membrane consisting of at least one fiber selected from polyester, polypropylene, nylon, polyethylene, acrylic, rayon, acetate and cellulose.
The method of claim 1,
The hydrophilic selective layer is a method for producing a pressure-delayed osmotic membrane comprising at least one selected from polyamide, polypiperazine, polyphenylenediamine, polychlorophenylenediamine and polybenzidine.
A porous support layer;
A polymer support layer formed on the porous support layer and including an anionic compound and a polymer in a weight ratio of 1:18 to 15: 4; And
A hydrophilic selective layer formed on the polymer support layer;
Pressure delayed osmosis membrane comprising a. The method of claim 8,
The anionic compound and the polymer is a pressure delayed osmosis membrane is included in a weight ratio of 2:17 to 10: 9.
The method of claim 8,
The back of the pressure delayed osmosis membrane is a pressure delayed osmosis membrane having a zeta potential potential of 25 to -70 mV at a pH of 5 to 10.
The method of claim 8,
The reverse side of the pressure delayed osmosis membrane is a pressure delayed osmosis membrane having a zeta potential of -35 to 70 mV at a pH of 8 to 10.
The method of claim 8,
The pressure delayed osmosis membrane has a PRO reduction ratio of 25 ° C., a pressure of 20 bar, a flow rate of 0.5 LPM, and a pH of 6 with respect to 100 ppm sodium alginate as an induction solution and a sodium chloride solution of 70000 ppm as a feed solution. Pressure-Delayed Osmotic Membrane Less Than%:
[Calculation 2]

In Formula 2, W ₁ is the power density of the initial pressure delayed osmosis membrane, W ₂ is the power density of the pressure delayed osmosis membrane after operating for 2 hours.
A pressure delayed osmosis module having a pressure delayed osmosis membrane according to any one of claims 8 to 12.

Images