High-flux high-desalination pollution-resistant reverse osmosis membrane and preparation method and application thereof

Abstract

The application belongs to the technical field of reverse osmosis membranes, and particularly relates to a high-flux high-desalination pollution-resistant reverse osmosis membrane and a preparation method and application thereof. The reverse osmosis membrane comprises a porous ultrafiltration base film and a polyamide separation membrane layer; the polyamide separation membrane layer is formed by interfacial polymerization reaction of an aqueous phase solution and an organic phase solution on the surface of the porous ultrafiltration base film; the aqueous phase solution comprises a polyamine monomer and a supramolecular solvent; the supramolecular solvent is prepared from polyglycerol, crotonic acid, an amino acid and deionized water; and the polyamide separation membrane layer is grafted with itaconic acid-gamma-cyclodextrin unsaturated monomers. The reverse osmosis membrane provided by the application has a desalination rate of > 99.5%, a water flux of > 67L / m 2 h, and a water flux decrease rate of < 7% and a water flux recovery rate of > 98% after running for 8h.

Description

Technical Field

[0001] This invention belongs to the field of reverse osmosis membrane technology, specifically relating to a high-flux, high-desalination, and fouling-resistant reverse osmosis membrane, its preparation method, and its application. Background Technology

[0002] Polyamide reverse osmosis membranes are widely used in seawater desalination, municipal wastewater purification, and industrial ultrapure water production. However, the development of high-performance reverse osmosis membranes still faces many serious challenges: First, it is difficult to achieve a synergistic improvement in water flux and salt rejection rate of polyamide reverse osmosis membranes. This problem stems from the structural characteristics of polyamide reverse osmosis membranes: while increasing the density of polyamide reverse osmosis membranes is beneficial to enhancing the salt ion rejection capacity of the desalination layer, it will lead to a decrease in the connectivity of water molecule transport channels, thereby reducing water flux; conversely, reducing the density of polyamide reverse osmosis membranes to increase water flux will inevitably sacrifice the desalination rate. Second, polyamide reverse osmosis membranes are susceptible to contaminant adhesion, among which membrane fouling caused by small molecule surfactants (sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, etc.) and large molecule organic contaminants (proteins, etc.) is particularly prominent. The adsorption or deposition of contaminants on the membrane surface will lead to membrane flux decline, increased operating pressure, and increased cleaning frequency, which will not only significantly increase operating costs but also shorten the membrane's service life.

[0003] Existing antifouling reverse osmosis membranes mostly focus on the antifouling properties against a single pollutant. For example, Chinese patent CN 115463548 B discloses an antifouling reverse osmosis membrane and its preparation method, which includes the following steps: (1) preparation of antifouling coating liquid, including the following raw materials in 100% by weight percentage: 0.4-1% of diepoxide compounds, 0.05-2% of cyclodextrin or its derivatives, 0.01-0.2% of diamino-substituted anthracene compounds, and the balance being alcohol solvent and water; (2) coating the antifouling coating liquid onto one surface of a polyamide reverse osmosis membrane, and obtaining an antifouling reverse osmosis membrane with a modified cyclodextrin coating on the surface after heat treatment; this technical solution has good antifouling properties against small molecule surfactants (hexadecyltrimethylammonium bromide), but this technical solution is a surface coating method, which has the risk of easy peeling, which may cause a significant decrease in the antifouling efficiency of the membrane element during long-term use.

[0004] Chinese Patent CN 113634130 B discloses a fouling-resistant reverse osmosis membrane, its preparation method, and its application. The reverse osmosis membrane comprises a support layer, a separation layer, and a fouling-resistant layer stacked sequentially. The separation layer is a polyamide layer, and the fouling-resistant layer is a polyvinylpyrrolidone layer, wherein the polyvinylpyrrolidone is cross-linked with the polyamide through carbon-carbon double bonds. This technical solution exhibits good antifouling properties against large molecular organic pollutants (bovine serum albumin). However, protein molecules are relatively large and mainly deposit on the membrane surface through hydrophobic interactions or steric hindrance, resulting in a weaker direct pore-clogging effect compared to small molecule surfactants. Furthermore, protein fouling is mostly surface deposition, making it relatively easy to remove through hydrodynamic washing. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a high-flux, high-desalination, and fouling-resistant reverse osmosis membrane, its preparation method, and its applications. The reverse osmosis membrane provided by this invention has a desalination rate >99.5% and a water flux >67 L / m³. 2 After running for 8 hours, the water flux of a mixed aqueous solution containing 1000 ppm bovine serum albumin, 200 ppm hexadecyltrimethylammonium bromide, or 200 ppm sodium dodecyl sulfate decreased by less than 7%, and the water flux recovery rate was greater than 98%.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of the present invention provides a high-flux, high-desalination, fouling-resistant reverse osmosis membrane, comprising a porous ultrafiltration base membrane and a polyamide separation membrane layer; The polyamide separation membrane layer is formed by interfacial polymerization of aqueous solution and organic solution on the surface of a porous ultrafiltration membrane. The aqueous solution comprises a polyamine monomer and a supramolecular solvent; The supramolecular solvent is prepared from polyglycerol, crotonic acid, amino acids and deionized water; The polyamide separation membrane layer is grafted with itaconic acid-γ-cyclodextrin unsaturated monomers.

[0007] In this invention, there are no special requirements for the specific selection of the porous ultrafiltration base membrane. Conventional types in the art can be selected, including but not limited to cellulose acetate membranes, polyethersulfone membranes, polyvinylidene fluoride membranes, polysulfone membranes, or polyacrylonitrile membranes with a pore size range of 10-100 nm.

[0008] Preferably, the thickness of the porous ultrafiltration membrane is 50-150µm.

[0009] In this invention, there are no special requirements for the specific selection of the polyamine monomer; conventional types in the art can be selected, including but not limited to m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, piperazine, or pyromellitic triamine.

[0010] Preferably, the concentration of the polyamine monomer in the aqueous solution is 1-3 wt%.

[0011] Preferably, the supramolecular solvent is prepared by mixing polyglycerol, crotonic acid and amino acids, stirring to obtain a viscous liquid, and then adding deionized water to adjust the water content to 60-80 wt%.

[0012] Preferably, the molar ratio of polyglycerol, crotonic acid and amino acids is 0.5-0.6:0.5-0.6:2-3.

[0013] Preferably, the stirring temperature is 50-80℃, the stirring speed is 300-600 r / min, and the stirring time is 1-4 h.

[0014] Preferably, the polyglycerol is selected from at least one of polyglycerol-3, polyglycerol-6, and polyglycerol-10.

[0015] Preferably, the amino acid is selected from at least one of L-arginine, L-histidine, and L-lysine.

[0016] In this invention, the organic phase solution comprises a polyacrylamide chloride monomer and an organic solvent.

[0017] In this invention, there are no special requirements for the specific selection of the polyacrylamide chloride monomer. Conventional types in the art can be selected, including but not limited to arylpyridinyl chloride, isophthaloyl chloride, or terephthaloyl chloride.

[0018] In this invention, there are no special requirements for the specific selection of the organic solvent; any conventional type in the art can be selected, including but not limited to n-hexane, cyclohexane, n-heptane, n-decane, or toluene.

[0019] Preferably, the concentration of polyacrylamide chloride monomer in the organic phase solution is 0.1-0.5 wt%.

[0020] Preferably, the preparation method of the itaconic acid-γ-cyclodextrin unsaturated monomer is as follows: itaconic acid, γ-cyclodextrin and catalyst are mixed and heated to carry out esterification reaction. After the reaction is completed, the monomer is purified and dried to obtain the product.

[0021] Preferably, the mass ratio of itaconic acid, γ-cyclodextrin and catalyst is 1:1-3:1-3.

[0022] Preferably, the catalyst is sodium hypophosphite or sodium dihydrogen phosphate.

[0023] Preferably, the esterification reaction is carried out at a temperature of 120-160°C for 1-3 hours.

[0024] Preferably, the purification involves dissolving the product obtained after the esterification reaction in water, recrystallizing it with ethanol, and finally washing it.

[0025] A second aspect of this invention provides a method for preparing a high-flux, high-desalination, fouling-resistant reverse osmosis membrane, comprising the following steps: The porous ultrafiltration membrane is immersed in an aqueous solution, removed and the surface aqueous solution is removed, then immersed in an organic solution for interfacial polymerization, removed and the surface organic solution is removed, then immersed in a supramolecular solvent, removed and the surface supramolecular solvent is removed, and heat-treated to obtain a primary composite membrane. The primary composite membrane is placed in a methanol-water solution containing itaconic acid-γ-cyclodextrin unsaturated monomer and photoinitiator. The methanol-water solution containing itaconic acid-γ-cyclodextrin unsaturated monomer and photoinitiator is then removed and subjected to ultraviolet irradiation to obtain a high-flux, high-desalination, and fouling-resistant reverse osmosis membrane.

[0026] Preferably, the porous ultrafiltration membrane is in contact with the aqueous solution at a temperature of 25-30°C for a time of 5-100 seconds.

[0027] Preferably, the porous ultrafiltration membrane is in contact with the organic phase solution at a temperature of 25-30°C for a time of 5-100 seconds.

[0028] Preferably, the porous ultrafiltration membrane is in contact with the supramolecular solvent at a temperature of 25-30°C for a time of 5-100 seconds.

[0029] Preferably, the heat treatment temperature is 50-80℃ and the time is 1-10 min.

[0030] Preferably, the mass concentration of the itaconic acid-γ-cyclodextrin unsaturated monomer is 0.2-1%.

[0031] In this invention, there is no particular limitation on the type of photoinitiator, and conventional types in the art can be selected, including but not limited to benzophenone, 4-hydroxybenzophenone, 4-aminobenzophenone, 1-hydroxy-cyclohexyl-phenyl ketone or 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0032] Preferably, the mass concentration of the photoinitiator is 0.01-0.05%.

[0033] Preferably, the volume ratio of the methanol to the aqueous solution is 1:1.

[0034] Preferably, the contact time between the primary composite membrane and the methanol aqueous solution containing itaconic acid-γ-cyclodextrin unsaturated monomer and photoinitiator is 5-20 s, and the contact temperature is 30-40 ℃.

[0035] Preferably, the wavelength of the ultraviolet irradiation is 365 nm and the duration is 10-40 s.

[0036] The third aspect of this invention provides an application of a high-flux, high-desalination, fouling-resistant reverse osmosis membrane in the field of water treatment.

[0037] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: Some existing technologies claim that grafting amino acids onto the membrane surface can improve the water flux and fouling resistance of reverse osmosis membranes. However, the inventors found in their experiments that reverse osmosis membranes obtained solely by grafting amino acids not only have limited improvements in water flux and fouling resistance, but also have low desalination rates.

[0038] This invention creatively employs polyglycerol, crotonic acid, and amino acids to prepare a supramolecular solvent, which has three functions: First, it can regulate the interfacial polymerization process of polyamide separation membranes through hydrogen bonding with polyamine monomers, resulting in polyamide separation membranes with excellent hydrophilicity and narrow pore size distribution, thereby enabling reverse osmosis membranes to achieve both high flux and high desalination rate; Second, it can consume unreacted acyl chloride groups, avoiding the generation of carboxyl groups in polyamide separation membranes, thereby improving the fouling resistance of reverse osmosis membranes; Third, it introduces polymerizable double bonds on the surface of polyamide separation membranes, allowing itaconic acid-γ-cyclodextrin unsaturated monomers to be grafted onto the surface of polyamide separation membranes under the action of photoinitiators, thereby further improving the flux and fouling resistance of reverse osmosis membranes.

[0039] In this invention, an itaconic acid-γ-cyclodextrin unsaturated monomer was prepared by esterification of itaconic acid and γ-cyclodextrin. Grafting it onto the surface of a polyamide separation membrane not only further improves the hydrophilicity and fouling resistance of the reverse osmosis membrane, but also the unique three-dimensional cavity structure of cyclodextrin facilitates the permeation of water molecules, thereby further improving the water flux of the reverse osmosis membrane.

[0040] The fouling resistance claimed by existing reverse osmosis membranes is usually for a single pollutant. The reverse osmosis membrane provided by this invention has excellent fouling resistance to cationic small molecule surfactants, anionic small molecule surfactants and macromolecular organic pollutants. As verified by experiments, after running for 8 hours in a mixed aqueous solution containing 1000 ppm bovine serum albumin, 200 ppm hexadecyltrimethylammonium bromide or 200 ppm sodium dodecyl sulfate, the water flux decrease rate was <7% and the water flux recovery rate was greater than 98%. Attached Figure Description

[0041] Figure 1 The bar chart shows the desalination rates of the reverse osmosis membranes in Examples 1-2 and Comparative Examples 1-7. Figure 2 Bar charts showing the water flux of the reverse osmosis membranes in Examples 1-2 and Comparative Examples 1-7; Figure 3 Bar chart showing the fouling resistance (water flux reduction rate) of the reverse osmosis membranes in Examples 1-2 and Comparative Examples 1-7; Figure 4 The bar chart shows the fouling resistance (water flux recovery rate) of the reverse osmosis membranes in Examples 1-2 and Comparative Examples 1-7. Detailed Implementation

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Example 1 This example provides a high-flux, high-desalination, fouling-resistant reverse osmosis membrane: Preparation of supramolecular solvent: Polyglycerol (polyglycerol-3), crotonic acid and amino acid (L-arginine) were mixed in a molar ratio of 0.5:0.5:2 and stirred at 80℃ and 400r / min for 3h to obtain a viscous liquid. Deionized water was added to adjust the water content to 70wt%.

[0044] Preparation of aqueous solution: Mix polyamine monomer (m-phenylenediamine) and supramolecular solvent at a mass ratio of 2:98 and stir until homogeneous.

[0045] Preparation of organic phase solvent: Mix polyacrylamide chloride monomer (pyromellitic trimethylol chloride) and organic solvent (n-hexane) at a mass ratio of 0.3:99.7 and stir until homogeneous.

[0046] Preparation of primary composite membrane: A porous ultrafiltration base membrane (a polysulfone membrane with a pore size of 30 nm and a thickness of 120 µm) is immersed in an aqueous solution and contacted at 25 °C for 20 s. The membrane is then removed and the surface aqueous solution is removed. The membrane is then immersed in an organic solution for interfacial polymerization reaction and contacted at 25 °C for 20 s. The surface organic solution is then removed and the membrane is then removed. The membrane is then immersed in a supramolecular solvent and contacted at 25 °C for 20 s. The surface supramolecular solvent is then removed and the membrane is then heat-treated at 65 °C for 3 min to obtain the final product.

[0047] Preparation of itaconic acid-γ-cyclodextrin unsaturated monomer: Itaconic acid, γ-cyclodextrin and catalyst (sodium hypophosphite) were mixed in a mass ratio of 1:1:1 and heated to 140℃ for esterification reaction for 1 hour. After the esterification reaction was completed, the product was first dissolved in water, then recrystallized with ethanol, and finally washed and dried to obtain the final product.

[0048] Preparation of methanol aqueous solution containing itaconic acid-γ-cyclodextrin unsaturated monomer and photoinitiator: mix itaconic acid-γ-cyclodextrin unsaturated monomer, photoinitiator (benzophenone) and methanol aqueous solution (volume ratio of 1:1) at a mass ratio of 0.5:0.03:99.47 and stir until homogeneous.

[0049] Preparation of reverse osmosis membrane: The primary composite membrane is placed in a methanol aqueous solution containing itaconic acid-γ-cyclodextrin unsaturated monomer and photoinitiator, and contacted at 35°C for 20s. The methanol aqueous solution containing itaconic acid-γ-cyclodextrin unsaturated monomer and photoinitiator is then removed and subjected to ultraviolet light irradiation at a wavelength of 365nm for 30s to obtain the membrane.

[0050] Example 2 This example provides a high-flux, high-desalination, fouling-resistant reverse osmosis membrane: Preparation of supramolecular solvent: Polyglycerol (polyglycerol-3), crotonic acid and amino acid (L-arginine) were mixed in a molar ratio of 0.5:0.5:2 and stirred at 80℃ and 400r / min for 3h to obtain a viscous liquid. Deionized water was added to adjust the water content to 70wt%.

[0051] Preparation of aqueous solution: Mix polyamine monomer (m-phenylenediamine) and supramolecular solvent at a mass ratio of 2.5:97.5 and stir until homogeneous.

[0052] Preparation of organic phase solvent: Mix polyacrylamide chloride monomer (pyromellitic trimethylol chloride) and organic solvent (n-hexane) at a mass ratio of 0.15:99.85 and stir until homogeneous.

[0053] Preparation of primary composite membrane: A porous ultrafiltration base membrane (a polysulfone membrane with a pore size of 30 nm and a thickness of 120 µm) is immersed in an aqueous solution and contacted at 25 °C for 30 s. The membrane is then removed and the surface aqueous solution is removed. The membrane is then immersed in an organic solution for interfacial polymerization (contact at 25 °C for 30 s). The membrane is then removed and the surface organic solution is removed. The membrane is then immersed in a supramolecular solvent and contacted at 25 °C for 30 s. The surface supramolecular solvent is then removed and the membrane is heat-treated at 65 °C for 3 min to obtain the final product.

[0054] Preparation of itaconic acid-γ-cyclodextrin unsaturated monomer: Itaconic acid, γ-cyclodextrin and catalyst (sodium hypophosphite) were mixed in a mass ratio of 0.8:1:1 and heated to 140℃ for esterification reaction for 1 h. After the esterification reaction was completed, the product was first dissolved in water, then recrystallized with ethanol, and finally washed and dried to obtain the final product.

[0055] Preparation of methanol aqueous solution containing itaconic acid-γ-cyclodextrin unsaturated monomer and photoinitiator: mix itaconic acid-γ-cyclodextrin unsaturated monomer, photoinitiator (benzophenone) and methanol aqueous solution (volume ratio 1:1) at a mass ratio of 1:0.05:98.95 and stir until homogeneous.

[0056] Preparation of reverse osmosis membrane: The primary composite membrane is placed in a methanol aqueous solution containing itaconic acid-γ-cyclodextrin unsaturated monomer and photoinitiator, and contacted at 35°C for 30s. The methanol aqueous solution containing itaconic acid-γ-cyclodextrin unsaturated monomer and photoinitiator is then removed, and ultraviolet light irradiation at a wavelength of 365nm is performed for 30s to obtain the membrane.

[0057] Comparative Example 1 The difference between this comparative example and Example 1 is as follows: preparation of supramolecular solvent: crotonic acid and amino acid (L-arginine) were mixed at a molar ratio of 1:2 and stirred at 80°C and 400 r / min for 3 h to obtain a viscous liquid. Deionized water was added to adjust the water content to 70 wt%. All other aspects are the same.

[0058] Comparative Example 2 The difference between this comparative example and Example 1 is as follows: preparation of supramolecular solvent: chloroform, crotonic acid and urea were mixed in a molar ratio of 0.5:0.5:2 and stirred at 80°C and 400 r / min for 3 h to obtain a viscous liquid. Deionized water was added to adjust the water content to 70 wt% to obtain the final product; all other aspects are the same.

[0059] Comparative Example 3 The difference between this comparative example and Example 1 is as follows: preparation of supramolecular solvent: glycerol, crotonic acid and amino acid (L-arginine) were mixed in a molar ratio of 0.5:0.5:2 and stirred at 80°C and 400 r / min for 3 h to obtain a viscous liquid. Deionized water was added to adjust the water content to 70 wt%.

[0060] Comparative Example 4 The difference between this comparative example and Example 1 is as follows: Aqueous solution preparation: The polyamine monomer (m-phenylenediamine) and water are mixed at a mass ratio of 2:98 and stirred until homogeneous; all other aspects are the same.

[0061] Comparative Example 5 The difference between this comparative example and Example 1 is as follows: Preparation of aqueous solution: Mix polyamine monomer (m-phenylenediamine) and water at a mass ratio of 2:98 and stir until homogeneous.

[0062] Preparation of organic phase solvent: Mix polyacrylamide chloride monomer (pyromellitic trimethylol chloride) and organic solvent (n-hexane) at a mass ratio of 0.3:99.7 and stir until homogeneous.

[0063] Preparation of reverse osmosis membrane: A porous ultrafiltration base membrane (polysulfone membrane with a pore size of 30 nm and a thickness of 120 µm) is immersed in an aqueous solution and contacted at 25 °C for 20 s. The membrane is then removed and the surface aqueous solution is removed. The membrane is then immersed in an organic solution for interfacial polymerization (contact at 25 °C for 20 s). The surface organic solution is then removed and the membrane is immersed in an aqueous solution containing 1.0 wt% L-arginine (pH 11) for 2 min. The surface L-arginine aqueous solution is then removed and the membrane is heat-treated at 60 °C for 10 min to obtain the final membrane.

[0064] Comparative Example 6 The difference between this comparative example and Example 1 is that the itaconic acid-γ-cyclodextrin unsaturated monomer is replaced with polyvinylpyrrolidone (number average molecular weight of 58,000), otherwise they are the same.

[0065] Comparative Example 7 The difference between this comparative example and Example 1 is as follows: Preparation of supramolecular solvent: Polyglycerol (polyglycerol-3), crotonic acid and amino acid (L-arginine) were mixed in a molar ratio of 0.5:0.5:2 and stirred at 80℃ and 400r / min for 3h to obtain a viscous liquid. Deionized water was added to adjust the water content to 70wt%.

[0066] Preparation of aqueous solution: Mix polyamine monomer (m-phenylenediamine) and supramolecular solvent at a mass ratio of 2:98 and stir until homogeneous.

[0067] Preparation of organic phase solvent: Mix polyacrylamide chloride monomer (pyromellitic trimethylol chloride) and organic solvent (n-hexane) at a mass ratio of 0.3:99.7 and stir until homogeneous.

[0068] Reverse osmosis membrane preparation: A porous ultrafiltration base membrane (a polysulfone membrane with a pore size of 30 nm and a thickness of 120 µm) is immersed in an aqueous solution and contacted at 25 °C for 20 s. The membrane is then removed and the surface aqueous solution is removed. The membrane is then immersed in an organic solution for interfacial polymerization (contact at 25 °C for 20 s). The membrane is then removed and the surface organic solution is removed. The membrane is then immersed in a supramolecular solvent and contacted at 25 °C for 20 s. The surface supramolecular solvent is then removed and the membrane is heat-treated at 65 °C for 3 min to obtain the final membrane.

[0069] Performance testing 1. Desalination rate: After the reverse osmosis membrane is installed in the membrane tank and pre-pressurized at 0.5 MPa for 0.5 h, the concentration changes of NaCl in the raw NaCl solution with an initial concentration of 2000 ppm and the permeate are measured within 1 h at a pressure of 1.55 MPa and a temperature of 25 °C. The desalination rate is then calculated using the following formula: R = (C p -C f ) / C p×100%, where R is the desalination rate, and C is the desalination rate. p C represents the concentration of NaCl in the original solution. f The concentration of NaCl in the permeate is given.

[0070] 2. Fouling Resistance: The reverse osmosis membrane was installed in the membrane tank and pre-pressurized at 0.5 MPa for 0.5 h. The water permeation rate of the reverse osmosis membrane was measured within 1 h at a pressure of 1.55 MPa and a temperature of 25℃. The test solution was a 2000 ppm NaCl aqueous solution. The water flux was calculated using the following formula: Q1=J / (A·t), where J is the water permeation rate (L), and Q1 is the water flux (L / m³). 2 h), A is the effective membrane area of ​​the reverse osmosis membrane (m²) 2 ), where t is time (h).

[0071] The test solutions were replaced with: a mixed aqueous solution of NaCl and bovine serum albumin (NaCl concentration 2000 ppm, bovine serum albumin concentration 1000 ppm); a mixed aqueous solution of NaCl and hexadecyltrimethylammonium bromide (NaCl concentration 2000 ppm, hexadecyltrimethylammonium bromide concentration 200 ppm); and a mixed aqueous solution of NaCl and sodium dodecyl sulfate (NaCl concentration 2000 ppm, sodium dodecyl sulfate concentration 1000 ppm). (Concentration of 200 ppm); After running for 8 hours, the water flux of the reverse osmosis membrane was measured as Q2; Then, after rinsing the reverse osmosis membrane with clean water for 0.5 hours, the water flux Q3 was measured when the circulating liquid was a 2000 ppm NaCl aqueous solution under the conditions of pressure 1.55 MPa and temperature 25℃; The water flux reduction rate of the reverse osmosis membrane was obtained by the following formula: D=(Q1-Q2) / Q1×100%; The water flux recovery rate of the reverse osmosis membrane after water washing was obtained by the following formula: H=Q3 / Q1×100%.

[0072] The test results are shown in Table 1 below. Figure 1-4 As shown.

[0073]

[0074] As shown in Table 1, the reverse osmosis membranes prepared in Examples 1 and 2 possess both high flux, high desalination capacity, and fouling resistance, with a desalination rate >99.5% and a water flux >67 L / m³. 2 After running for 8 hours, the water flux of a mixed aqueous solution containing 1000 ppm bovine serum albumin, 200 ppm hexadecyltrimethylammonium bromide, or 200 ppm sodium dodecyl sulfate decreased by less than 7%, and the water flux recovery rate was greater than 98%.

[0075] The changes in the composition of the supramolecular solvents in Comparative Examples 1-3 resulted in a decrease in the water flux and fouling resistance of the prepared reverse osmosis membranes. In Comparative Example 4, the absence of supramolecular solvents in the aqueous solution resulted in a decrease in the desalination rate, water flux, and fouling resistance of the prepared reverse osmosis membrane. In Comparative Example 5, the aqueous solution lacked supramolecular solvents, and the grafted itaconic acid-γ-cyclodextrin unsaturated monomer was replaced with grafted L-arginine. The resulting reverse osmosis membrane exhibited the worst water flux and fouling resistance. In Comparative Example 6, the unsaturated monomer of grafted itaconic acid-γ-cyclodextrin was replaced with grafted polyvinylpyrrolidone. Although the fouling resistance of the prepared reverse osmosis membrane did not decrease significantly, the water flux decreased significantly. In Comparative Example 7, the reverse osmosis membrane prepared without grafted itaconic acid-γ-cyclodextrin unsaturated monomers exhibited decreased water flux and fouling resistance.

[0076] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-flux, high-desalination, fouling-resistant reverse osmosis membrane, characterized in that, Includes a porous ultrafiltration base membrane and a polyamide separation membrane layer; The polyamide separation membrane layer is formed by interfacial polymerization of aqueous solution and organic solution on the surface of a porous ultrafiltration membrane. The aqueous solution comprises a polyamine monomer and a supramolecular solvent; The supramolecular solvent is prepared from polyglycerol, crotonic acid, amino acids and deionized water; The polyamide separation membrane layer is grafted with itaconic acid-γ-cyclodextrin unsaturated monomers.

2. The high-flux, high-desalination, fouling-resistant reverse osmosis membrane according to claim 1, characterized in that, The supramolecular solvent is prepared by mixing polyglycerol, crotonic acid and amino acids, stirring to obtain a viscous liquid, and then adding deionized water to adjust the water content to 60-80 wt%.

3. The high-flux, high-desalination, fouling-resistant reverse osmosis membrane according to claim 2, characterized in that, The polyglycerol is selected from at least one of polyglycerol-3, polyglycerol-6, and polyglycerol-10.

4. The high-flux, high-desalination, fouling-resistant reverse osmosis membrane according to claim 3, characterized in that, The amino acid is selected from at least one of L-arginine, L-histidine, and L-lysine.

5. The high-flux, high-desalination, fouling-resistant reverse osmosis membrane according to any one of claims 1-4, characterized in that, The organic phase solution comprises polyacrylamide chloride monomers and organic solvents.

6. The high-flux, high-desalination, fouling-resistant reverse osmosis membrane according to claim 5, characterized in that, The preparation method of the itaconic acid-γ-cyclodextrin unsaturated monomer is as follows: mix itaconic acid, γ-cyclodextrin and catalyst, heat to carry out esterification reaction, and after the reaction is completed, purify and dry to obtain the product.

7. The high-flux, high-desalination, fouling-resistant reverse osmosis membrane according to claim 5, characterized in that, The reverse osmosis membrane has a desalination rate >99.5% and a water flux >67 L / m³. 2 After running for 8 hours, the water flux of a mixed aqueous solution containing 1000 ppm bovine serum albumin, 200 ppm hexadecyltrimethylammonium bromide, or 200 ppm sodium dodecyl sulfate decreased by less than 7%, and the water flux recovery rate was greater than 98%.

8. The method for preparing the high-flux, high-desalination, fouling-resistant reverse osmosis membrane according to any one of claims 1-7, characterized in that, Includes the following steps: The porous ultrafiltration membrane is immersed in an aqueous solution, removed and the surface aqueous solution is removed, then immersed in an organic solution for interfacial polymerization, removed and the surface organic solution is removed, then immersed in a supramolecular solvent, removed and the surface supramolecular solvent is removed, and heat-treated to obtain a primary composite membrane. The primary composite membrane is placed in a methanol-water solution containing itaconic acid-γ-cyclodextrin unsaturated monomer and photoinitiator. The methanol-water solution containing itaconic acid-γ-cyclodextrin unsaturated monomer and photoinitiator is then removed and subjected to ultraviolet irradiation to obtain a high-flux, high-desalination, and fouling-resistant reverse osmosis membrane.

9. The method for preparing a high-flux, high-desalination, fouling-resistant reverse osmosis membrane according to claim 8, characterized in that, The contact time between the porous ultrafiltration membrane and the aqueous solution is 5-100 seconds. The contact time between the porous ultrafiltration membrane and the organic phase solution is 5-100 s; The contact time between the porous ultrafiltration membrane and the supramolecular solvent is 5-100 s; The contact time between the primary composite membrane and the methanol aqueous solution containing itaconic acid-γ-cyclodextrin unsaturated monomer and photoinitiator is 5-20 s.

10. The application of the reverse osmosis membrane prepared by the method of preparing the high-flux, high-desalination, and fouling-resistant reverse osmosis membrane according to any one of claims 1-7 or any one of claims 8-9 in the field of water treatment.

Images