High-flux anti-pollution reverse osmosis membrane and preparation method thereof

Abstract

The invention discloses a high-flux anti-pollution reverse osmosis membrane and a preparation method thereof, and relates to the technical field of reverse osmosis membrane preparation. A diamine monomer, a diacyl chloride monomer and zinc acetate are used as raw materials, a flat plate fiber membrane containing ZnO is prepared through an electrostatic spinning technology, then the flat plate fiber membrane is subjected to surface modification, and finally MXene nanosheets are loaded on the surface of the flat plate fiber membrane. Due to surface modification, the flat plate fiber membrane has good hydrophilicity, the water passing rate is increased, pollutants are prevented from being in direct contact with the surface of the flat plate fiber membrane, pollutant adsorption is reduced, and the anti-pollution performance of the flat plate fiber membrane is improved; znO and MXene nanosheets have a synergistic effect, the interlayer spacing is enlarged through a steric hindrance effect, the ionized water interaction is jointly adjusted, the transmission path of water molecules is optimized, the selective rejection of salt ions is enhanced, and the salt rejection rate is increased.

Description

Technical Field

[0001] The invention relates to the technical field of reverse osmosis membrane preparation, in particular to a high-flux anti-pollution reverse osmosis membrane and a preparation method thereof. Background Art

[0002] As the core of reverse osmosis technology, reverse osmosis membrane plays an important role in water treatment technology. Its working principle is to make water molecules in sewage permeate against the concentration gradient by applying pressure, so as to achieve the effect of intercepting pollutants such as dissolved salts, organic matter, and microorganisms. Reverse osmosis technology originated from seawater desalination research in the 1950s, and then gradually expanded to the fields of high-salt industrial wastewater treatment and municipal sewage reuse. In the prior art, there are two main types of reverse osmosis membranes, namely cellulose acetate membrane and polyamide composite membrane. Among them, cellulose acetate membrane is less used due to poor heat resistance and high operating pressure. Polyamide composite membrane has good thermal stability and mechanical stability and is widely used.

[0003] The traditional polyamide composite membrane has three layers, namely a non-woven fabric layer, a polysulfone porous layer and a polyamide functional layer. Patent CN202210687721.9 discloses a high-flux antibacterial reverse osmosis membrane and its preparation method and application. The obtained reverse osmosis membrane has a multi-layer structure, and the layers are tightly connected, which prolongs the service life of the reverse osmosis membrane, but the production cost is high and the preparation process is complicated.

[0004] Therefore, we propose a high-flux anti-fouling reverse osmosis membrane and a preparation method thereof. Summary of the invention

[0005] The object of the present invention is to provide a high-flux anti-pollution reverse osmosis membrane and a preparation method thereof, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for preparing a high-flux anti-pollution reverse osmosis membrane, comprising the following steps: Step (1): pouring a hexadecene solution onto the surface of the polyamide flat fiber membrane, reacting for 5 to 15 minutes, pouring out the excess solution, washing the surface of the fiber membrane, and then pouring a hydroxypropyl-β-cyclodextrin solution onto the surface of the polyamide flat fiber membrane, reacting for 5 to 15 minutes, pouring out the excess solution, washing the surface of the fiber membrane, and obtaining a modified polyamide flat fiber membrane; Step (2): The MXene nanosheet dispersion is loaded onto the modified polyamide flat fiber membrane by vacuum filtration and dried to obtain a reverse osmosis membrane.

[0007] Furthermore, in step (1), the preparation process of the hexacol solution is as follows: The triethylamine and deionized water were mixed in a mass ratio of 1:90, stirred evenly to obtain a mixed solution, and then hexadecene was added to obtain a hexadecene solution.

[0008] Furthermore, the mass ratio of the mixed solution to hexadecene is 1:0.1.

[0009] Furthermore, in step (1), the preparation process of the hydroxypropyl-β-cyclodextrin solution is as follows: Hydroxypropyl-β-cyclodextrin and deionized water were mixed in a mass ratio of 1:90 and stirred evenly to obtain a hydroxypropyl-β-cyclodextrin solution.

[0010] Furthermore, the mass ratio of the polyamide flat fiber membrane, the hexadecene solution and the hydroxypropyl-β-cyclodextrin solution is 1:(1~3):(1~3).

[0011] Furthermore, in step (2), the mass ratio of the MXene nanosheet dispersion to the modified polyamide flat fiber membrane is 10:(3-8).

[0012] Furthermore, in step (2), the drying process conditions are: temperature 45-65°C, time 25-45 min.

[0013] In the above technical scheme, hexapentol is grafted onto the surface of the polyamide flat fiber membrane through the reaction of the hydroxyl groups of hexapentol with the acyl chloride groups of the polyamide flat fiber membrane. The multiple hydroxyl groups in hexapentol form hydrogen bonds with water molecules to promote the transfer of water molecules and form a hydration layer to prevent pollutants from directly contacting the surface of the fiber membrane, reduce the adsorption of pollutants, and improve the anti-fouling performance of the fiber membrane. Hexapentol has good hydrophilicity and can improve water permeability. The hydroxyl groups of hydroxypropyl-β-cyclodextrin undergo interfacial polymerization reaction with the residual acyl chloride groups to construct a polyester protective layer on the surface of the fiber membrane, reduce the surface roughness of the fiber membrane, increase its hydrophilicity, and give the fiber membrane good high temperature resistance, reduce the flux attenuation caused by membrane pollution, and extend its service life.

[0014] Furthermore, in step (1), the polyamide flat fiber membrane is prepared by the following process: Diamine monomer, diacyl chloride monomer, zinc acetate and solvent are mixed, stirred and reacted under the protection of nitrogen atmosphere to obtain a spinning solution, which is then transferred to a syringe and electrospun on an injection pump to obtain a flat membrane. The flat membrane is heat-treated, then placed in a growth solution for heating reaction, and taken out to obtain a polyamide flat fiber membrane.

[0015] Furthermore, the mass ratio of the diamine monomer, the diacyl chloride monomer and the zinc acetate to the solvent is 1:1:(3-5):(6-10).

[0016] Furthermore, the process conditions of the stirring reaction are: temperature 0~20°C, time 1~3h, and rotation speed 80~90r / min.

[0017] Furthermore, the viscosity of the spinning solution is 1-20 Pa·s.

[0018] Furthermore, the process conditions of electrospinning are: voltage 10~18kV, feed rate 0.5~0.7mL / h, syringe needle tip distance to collector 10~16cm, humidity 10~30%, time 1.5~2h.

[0019] Furthermore, the process conditions of the heat treatment are: temperature 100~130℃, time 8~10h.

[0020] Furthermore, the process conditions of the heating reaction are: temperature 80~100°C, time 6~10h.

[0021] Furthermore, the diamine monomer is a mixture of one or more of m-phenylenediamine, hexamethylenediamine, 1,4-butanediamine, dodecanediamine, tetramethylhexamethylenediamine, and p-phenylenediamine.

[0022] Further, the diacid chloride monomer is a mixture of one or more of adipoyl chloride, sebacoyl chloride, dodecanedioyl chloride, terephthaloyl chloride, isophthaloyl chloride, 2,6-naphthalene dicarboxylic acid chloride and 1,4-cyclohexane dicarboxylic acid chloride.

[0023] Furthermore, the solvent is a mixed solution of a polar aprotic organic solvent and an inorganic salt co-solvent in a mass ratio of 1:(1-9).

[0024] Further, the polar aprotic organic solvent is a mixture of one or more of DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), DMAc (N,N-dimethylacetamide), and NMP (N-methylpyrrolidone); The inorganic salt cosolvent is CaCl 2 A mixture of one or more of LiBr (calcium chloride), LiBr (lithium bromide), and LiCl (lithium chloride).

[0025] Furthermore, the growth liquid is a mixed solution of zinc nitrate and 0.1 mol / L hexamethylenetetramine aqueous solution in a mass ratio of 1:1.

[0026] Furthermore, in step (2), the MXene nanosheet dispersion is prepared by the following process: S1: Ti 3 AlC 2 (titanium aluminum carbide), LiF (lithium fluoride) and hydrochloric acid solution are mixed, stirred for reaction, centrifuged for the first time, washed, the precipitate after centrifugation is mixed with pure water, ultrasonicated under the protection of nitrogen atmosphere, centrifuged for the second time, and the upper layer liquid after centrifugation is freeze-dried to obtain MXene nanosheets; S2: Mix MXene nanosheets and buffer solution, and disperse them by ultrasonic to obtain MXene nanosheet dispersion.

[0027] Furthermore, in S1, Ti 3 AlC 2 , the ratio of LiF to hydrochloric acid solution is (2~4) g: (3~5) g: (100~200) mL; The mass ratio of precipitate to pure water is 1:(10~20).

[0028] Furthermore, the mass fraction of the hydrochloric acid solution is 36%.

[0029] Furthermore, in S1, the instrument model used for ultrasound is LD-CP650, and the process conditions of ultrasound are: power 300~500W, time 4~6h.

[0030] Furthermore, in S1, the process conditions of the first centrifugation are: speed 3000-5000 rpm, time 4-6 min; The process conditions for the second centrifugation are: rotation speed 8000~10000rpm, time 20~30min.

[0031] Furthermore, in S1, the freeze-drying process conditions are: temperature -20~-10°C, time 36~48h.

[0032] Furthermore, in S2, the mass ratio of MXene nanosheets and buffer solution is 1:(10~20).

[0033] Further, the buffer solution preparation method is as follows: Tris(hydroxymethylaminomethane) hydrochloride was mixed with pure water in a ratio of 0.1 g:50 mL, and the pH value was adjusted to 8.5 to obtain a buffer solution.

[0034] In the above technical scheme, a nanofiber membrane containing ZnO is prepared by electrospinning technology using diamine monomer, diacyl chloride monomer and zinc acetate as raw materials. However, spinning ZnO as a raw material will lead to uneven distribution and polymerization. Therefore, zinc acetate is used and then heat-treated to form ZnO seeds. The hexamethylenetetramine in the growth solution is heated and hydrolyzed to release OH - , zinc nitrate dissociates to provide Zn 2+ , the two combine to form Zn(OH) 2 The intermediate is then dehydrated to form ZnO nuclei. ZnO seeds provide heterogeneous nucleation sites, reduce the nucleation energy barrier, and promote the growth of ZnO. ZnO can trigger redox reactions under ultraviolet irradiation, decompose organic pollutants in water, and combine with fiber membranes to synergistically improve the filtration performance of reverse osmosis membranes. At the same time, the polar surface of ZnO enhances the hydrophilicity of the fiber membrane, further improves the water flux, and reduces membrane pollution. The surface of MXene nanosheets is hydrophilic and has high porosity. The MXene nanosheets are loaded on the fiber membrane through vacuum filtration technology, which further enhances the flux of the reverse osmosis membrane. The conductive network of MXene nanosheets can quickly move charges and reduce the pollution caused by charge accumulation on the membrane surface. In addition, ZnO and MXene nanosheets work synergistically to expand the interlayer spacing through the steric hindrance effect, jointly regulate ion hydration, optimize the transmission path of water molecules, enhance the selective rejection of salt ions, and improve the desalination rate.

[0035] Compared with the prior art, the present invention has the following beneficial effects: 1. The hydroxyl groups of hexadecene are reacted with the acyl chloride groups of the polyamide flat fiber membrane to graft hexadecene onto the surface of the polyamide flat fiber membrane. The multiple hydroxyl groups in hexadecene form hydrogen bonds with water molecules to promote the transfer of water molecules and form a hydration layer to prevent pollutants from directly contacting the surface of the fiber membrane, reduce the adsorption of pollutants, and improve the anti-fouling performance of the fiber membrane. Hexadecene has good hydrophilicity and can improve water permeability. The hydroxyl groups of hydroxypropyl-β-cyclodextrin undergo interfacial polymerization reaction with the residual acyl chloride groups to construct a polyester protective layer on the surface of the fiber membrane, reduce the surface roughness of the fiber membrane, increase its hydrophilicity, and give the fiber membrane good high temperature resistance, reduce the flux attenuation caused by membrane pollution, and extend its service life.

[0036] 2. Using diamine monomer, diacyl chloride monomer and zinc acetate as raw materials, a nanofiber membrane containing ZnO was prepared by electrospinning technology. However, spinning ZnO as a raw material will lead to uneven distribution and polymerization. Therefore, zinc acetate was used and then heat-treated to form ZnO seeds. The hexamethylenetetramine in the growth solution was heated and hydrolyzed to release OH - , zinc nitrate dissociates to provide Zn 2+ , the two combine to form Zn(OH) 2 The intermediate is then dehydrated to form ZnO nuclei. ZnO seeds provide heterogeneous nucleation sites, reduce the nucleation energy barrier, and promote the growth of ZnO. ZnO can trigger redox reactions under ultraviolet irradiation, decompose organic pollutants in water, and combine with fiber membranes to synergistically improve the filtration performance of reverse osmosis membranes. At the same time, the polar surface of ZnO enhances the hydrophilicity of the fiber membrane, further improves the water flux, and reduces membrane pollution. The surface of MXene nanosheets is hydrophilic and has high porosity. The MXene nanosheets are loaded on the fiber membrane through vacuum filtration technology, which further enhances the flux of the reverse osmosis membrane. The conductive network of MXene nanosheets can quickly move charges and reduce the pollution caused by charge accumulation on the membrane surface. In addition, ZnO and MXene nanosheets work synergistically to expand the interlayer spacing through the steric hindrance effect, jointly regulate ion hydration, optimize the transmission path of water molecules, enhance the selective rejection of salt ions, and improve the desalination rate. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the following specific implementations, Triethylamine, CAS number 121-44-8, from Nanjing Reagent; Hexanehexasol, CAS number 69-65-8, from Merck reagents; Hydroxypropyl-β-cyclodextrin, CAS No. 94035-02-6, from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.; Zinc acetate, CAS number 557-34-6, from Hubei Xinghengye Technology Co., Ltd.; m-phenylenediamine, CAS number 108-45-2, from Merck reagents; Isophthaloyl chloride, CAS number 99-63-8, from Shanghai Yuanye Biotechnology Co., Ltd.; Zinc nitrate, CAS number 13778-30-8, from Merck Reagent; Hexamethylenetetramine, CAS number 100-97-0, from Nanjing Reagent; DMF, CAS number 127-19-5, from Merck reagents; LiBr, CAS No. 7550-35-8, was obtained from Hubei Shiteng Chemical Technology Co., Ltd.; Tris(hydroxymethyl)aminomethane hydrochloride, CAS No. 1185-53-1, from Wuhan Desheng Biochemical Technology Co., Ltd.; Ti 3 AlC 2 , CAS number is 12537-81-4, 500 mesh, from Ningbo Beijiaer New Materials Co., Ltd.; LiF, CAS No. 7789-24-4, from Shandong Duolian Chemical Co., Ltd.; Hydrochloric acid solution, CAS number 7647-01-0, mass fraction 36%, from Nanjing Reagent; NaCl, CAS No. 7647-14-5, from Langfang Pengcai Fine Chemical Co., Ltd.; Bovine serum albumin: CAS number is 9048-46-8, from Shanghai Jizhi Biochemical Technology Co., Ltd.; Prepare growth solution: mix zinc nitrate and 0.1 mol / L hexamethylenetetramine aqueous solution in a mass ratio of 1:1 to obtain growth solution; Prepare buffer solution: mix tris(hydroxymethylaminomethane) hydrochloride and pure water in a ratio of 0.1 g:50 mL, adjust the pH value to 8.5, and obtain a buffer solution; Prepare hexadecene solution: mix triethylamine and deionized water in a mass ratio of 1:90, stir evenly to obtain a mixed solution, and then add hexadecene to obtain a hexadecene solution; the mass ratio of the mixed solution to hexadecene is 1:0.1; Preparation of hydroxypropyl-β-cyclodextrin solution: Mix hydroxypropyl-β-cyclodextrin and deionized water in a mass ratio of 1:90, stir evenly, and obtain a hydroxypropyl-β-cyclodextrin solution.

[0039] Example 1: A method for preparing a high-flux anti-pollution reverse osmosis membrane, comprising the following steps: (1) Preparation of polyamide flat fiber membrane: DMF and LiBr are mixed in a mass ratio of 1:9 and stirred evenly to obtain a solvent; Mix m-phenylenediamine, isophthaloyl chloride, zinc acetate and solvent in a mass ratio of 1:1:5:10, and react at 90r / min at 0°C under nitrogen atmosphere for 3h to obtain a spinning solution, which is then transferred to a syringe and electrospun on an injection pump to obtain a flat membrane. The flat membrane is heat-treated and then placed in a growth solution heated to 100°C for 10h, and taken out to obtain a polyamide flat fiber membrane. The process conditions for electrospinning are: voltage 18kV, feed rate 0.7mL / h, syringe needle tip distance to collector 16cm, humidity 30%, time 2h; the process conditions for heat treatment are: temperature 130°C, time 10h; the viscosity of the spinning solution is 1Pa·s; (2) Preparation of MXene nanosheet dispersion: S1: Ti 3 AlC 2, LiF and hydrochloric acid solution are mixed in a ratio of 4g:5g:200mL, stirred for reaction, centrifuged for the first time, washed, the precipitate after centrifugation is mixed with pure water in a mass ratio of 1:20, ultrasonicated for 6h under nitrogen atmosphere protection, centrifuged for the second time, and the upper layer liquid after centrifugation is freeze-dried at -20℃ for 48h to obtain MXene nanosheets; S2: MXene nanosheets and buffer solution are mixed in a mass ratio of 1:20, ultrasonically dispersed to obtain MXene nanosheet dispersion; in S1, the process conditions for the first centrifugation are: speed 5000rpm, time 6min; the process conditions for the second centrifugation are: speed 10000rpm, time 30min, and in S1, the ultrasonic process conditions are: power 500W, time 6h; (3) Preparation of reverse osmosis membrane: Step (1): pouring hexadecene solution on the surface of polyamide flat fiber membrane, reacting for 15 minutes, pouring off the excess solution, washing the surface of fiber membrane, and then pouring hydroxypropyl-β-cyclodextrin solution, reacting for 15 minutes, pouring off the excess solution, washing the surface of fiber membrane, and obtaining modified polyamide flat fiber membrane; Step (2): loading MXene nanosheet dispersion on modified polyamide flat fiber membrane by vacuum filtration, drying, and obtaining reverse osmosis membrane; in step (1), the mass ratio of polyamide flat fiber membrane, hexadecene solution and hydroxypropyl-β-cyclodextrin solution is 1:3:3; in step (2), the mass ratio of MXene nanosheet dispersion and modified polyamide flat fiber membrane is 10:8; in step (2), the drying process conditions are: temperature 65°C, time 45min.

[0040] Example 2: A method for preparing a high-flux anti-pollution reverse osmosis membrane, comprising the following steps: (1) Preparation of polyamide flat fiber membrane: DMF and LiBr are mixed in a mass ratio of 1:5 and stirred evenly to obtain a solvent; Metaphenylenediamine, isophthaloyl chloride, zinc acetate and solvent were mixed in a mass ratio of 1:1:4:8, and stirred at 85r / min for 2h at 10°C under nitrogen atmosphere to obtain a spinning solution, which was then transferred to a syringe and electrospun on an injection pump to obtain a flat membrane. The flat membrane was heat-treated and then placed in a growth solution and heated to 90°C for 8h, and then taken out to obtain a polyamide flat fiber membrane. The process conditions for electrospinning were: voltage 15kV, feed rate 0.6mL / h, syringe needle tip distance to collector 13cm, humidity 20%, time 1.7h; the process conditions for heat treatment were: temperature 120°C, time 9h; the viscosity of the spinning solution was 10Pa·s; (2) Preparation of MXene nanosheet dispersion: S1: Ti 3 AlC2 , LiF and hydrochloric acid solution in a ratio of 3g:4g:150mL, stirred for reaction, centrifuged for the first time, washed, the precipitate after centrifugation was mixed with pure water in a mass ratio of 1:15, ultrasonicated for 5h under nitrogen atmosphere protection, centrifuged for the second time, and the upper layer liquid after centrifugation was freeze-dried at -15°C for 42h to obtain MXene nanosheets; S2: MXene nanosheets and buffer solution were mixed in a mass ratio of 1:15, ultrasonically dispersed to obtain MXene nanosheet dispersion; in S1, the process conditions for the first centrifugation were: speed 4000rpm, time 5min; the process conditions for the second centrifugation were: speed 9000rpm, time 25min, and in S1, the process conditions for ultrasound were: power 400W, time 5h; (3) Preparation of reverse osmosis membrane: Step (1): pouring hexadecene solution on the surface of polyamide flat fiber membrane, reacting for 10 minutes, pouring off the excess solution, washing the surface of fiber membrane, and then pouring hydroxypropyl-β-cyclodextrin solution, reacting for 10 minutes, pouring off the excess solution, washing the surface of fiber membrane, and obtaining modified polyamide flat fiber membrane; Step (2): loading MXene nanosheet dispersion on modified polyamide flat fiber membrane by vacuum filtration, drying, and obtaining reverse osmosis membrane; in step (1), the mass ratio of polyamide flat fiber membrane, hexadecene solution and hydroxypropyl-β-cyclodextrin solution is 1:2:2; in step (2), the mass ratio of MXene nanosheet dispersion and modified polyamide flat fiber membrane is 10:5; in step (2), the drying process conditions are: temperature 55°C, time 35min.

[0041] Example 3: A method for preparing a high-flux anti-fouling reverse osmosis membrane, comprising the following steps: (1) Preparation of polyamide flat fiber membrane: DMF and LiBr are mixed in a mass ratio of 1:1 and stirred to obtain a solvent; m-phenylenediamine, isophthaloyl chloride, zinc acetate and solvent were mixed in a mass ratio of 1:1:3:6, and stirred at 80r / min for 1h at 20°C under nitrogen atmosphere to obtain a spinning solution, which was then transferred to a syringe and electrospun on an injection pump to obtain a flat membrane. The flat membrane was heat-treated and then placed in a growth solution and heated to 80°C for 6h, and then taken out to obtain a polyamide flat fiber membrane. The process conditions for electrospinning were: voltage 10kV, feed rate 0.5mL / h, syringe needle tip distance to collector 10cm, humidity 10%, time 1.5h; the process conditions for heat treatment were: temperature 100°C, time 8h; the viscosity of the spinning solution was 20Pa·s; (2) Preparation of MXene nanosheet dispersion: S1: Ti 3AlC 2 , LiF and hydrochloric acid solution were mixed in a ratio of 2g:3g:100mL, stirred for reaction, centrifuged for the first time, washed, and the precipitate after centrifugation was mixed with pure water in a mass ratio of 1:10, ultrasonicated for 4h under nitrogen atmosphere protection, centrifuged for the second time, and the upper layer liquid after centrifugation was freeze-dried at -10℃ for 36h to obtain MXene nanosheets; S2: MXene nanosheets and buffer solution were mixed in a mass ratio of 1:10, ultrasonically dispersed, and MXene nanosheet dispersion was obtained; in S1, the process conditions for the first centrifugation were: speed 3000rpm, time 4min; the process conditions for the second centrifugation were: speed 8000rpm, time 20min, and in S1, the process conditions for ultrasound were: power 300W, time 4h; (3) Preparation of reverse osmosis membrane: Step (1): pouring hexadecene solution on the surface of polyamide flat fiber membrane, reacting for 5 minutes, pouring off the excess solution, washing the surface of fiber membrane, and then pouring hydroxypropyl-β-cyclodextrin solution, reacting for 5 minutes, pouring off the excess solution, washing the surface of fiber membrane, and obtaining modified polyamide flat fiber membrane; Step (2): loading MXene nanosheet dispersion on modified polyamide flat fiber membrane by vacuum filtration, drying, and obtaining reverse osmosis membrane; in step (1), the mass ratio of polyamide flat fiber membrane, hexadecene solution and hydroxypropyl-β-cyclodextrin solution is 1:1:1; in step (2), the mass ratio of MXene nanosheet dispersion and modified polyamide flat fiber membrane is 10:3; in step (2), the drying process conditions are: temperature 45°C, time 25min.

[0042] Comparative Example 1: Compared with Example 1, hexanehexol and hydroxypropyl-β-cyclodextrin were not used to graft-modify the polyamide flat fiber membrane, and other conditions remained unchanged.

[0043] Comparative Example 2: Compared with Example 1, zinc acetate is not added when preparing the polyamide flat fiber membrane, and MXene nanosheets are not loaded on the modified polyamide flat fiber membrane, and other conditions remain unchanged.

[0044] Comparative Example 3: Compared with Example 1, hexamethylenetetracycline and hydroxypropyl-β-cyclodextrin are not used to graft-modify the polyamide flat fiber membrane, and MXene nanosheets are not loaded on the modified polyamide flat fiber membrane, and other conditions remain unchanged.

[0045] Experiment: Take the reverse osmosis membranes obtained in Examples 1 to 3 and Comparative Examples 1 to 3 and perform various performance tests on them; A 2000 mg / L NaCl aqueous solution was prepared as the raw material solution and the cross-flow reverse osmosis membrane evaluation device (membrane pool effective area 29.2 cm 2), at 2.5MPa, 60℃, the water flux of the reverse osmosis membrane was tested (J w ) and salt rejection rate (R); ; ; J w ——Water flux, L / (m 2 h); V——permeate volume, L; M——effective area of ​​membrane, m 2 ; t——permeate collection time, h; C p ——NaCl mass concentration in the permeate; C f ——Mass concentration of NaCl in the raw material solution.

[0046] Using 2000 mg / L NaCl aqueous solution, the reverse osmosis membrane was pre-pressed at 2.5 MPa for 20 min to test the initial water flux J 0 , add bovine serum albumin (300 mg / L) into the NaCl aqueous solution, run at 2.5 MPa for 300 min, and test the water flux J every 30 min. t , then clean the reverse osmosis membrane and test the water flux after cleaning J wc , the operating conditions are the same as the initial ones, and the membrane flux decay rate (FDR) is calculated; ; The following table shows the test results of various performances of reverse osmosis membranes;

[0047] According to the data in the above table, we can draw the following conclusions: The reverse osmosis membranes obtained in Examples 1 to 3 are compared with those obtained in Comparative Examples 1 to 3. The test results show that: Compared with Example 1, Comparative Example 1 does not use hexadecene and hydroxypropyl-β-cyclodextrin to graft-modify the polyamide flat fiber membrane, and its water flux decreases significantly and the flux attenuation rate increases. The reason is that the surface of the fiber membrane formed by electrospinning is hydrophobic, while hexadecene and hydroxypropyl-β-cyclodextrin are both hydrophilic and can improve water permeability. Hexadecene can form a hydration layer on the surface of the fiber membrane to prevent pollutants from directly contacting the surface of the fiber membrane. Hydroxypropyl-β-cyclodextrin undergoes interfacial polymerization reaction with acyl chloride groups to construct a polyester protective layer on the surface of the fiber membrane, thereby reducing pollutant adsorption and improving the anti-fouling performance of the fiber membrane. Compared with Example 1, in Comparative Example 2, zinc acetate is not added when preparing the polyamide flat fiber membrane, and MXene nanosheets are not loaded on the modified polyamide flat fiber membrane, and the desalination rate decreases significantly. The reason is that zinc acetate forms ZnO under the action of heat treatment and growth liquid, and combines with MXene nanosheets to expand the interlayer spacing through the steric hindrance effect, jointly regulate ion hydration, optimize the transmission path of water molecules, enhance the selective rejection of salt ions, and improve the desalination rate; Compared with Example 1, Comparative Example 3 does not use hexacol and hydroxypropyl-β-cyclodextrin to graft modify the polyamide flat fiber membrane, and does not load MXene nanosheets on the modified polyamide flat fiber membrane. The water permeability and desalination rate are both reduced, and the flux attenuation rate is increased. It can be seen that the setting of the process and the materials used in this application can promote the improvement of the water permeability and desalination rate of the prepared reverse osmosis membrane and reduce the flux attenuation rate.

[0048] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing a high-throughput anti-pollution reverse osmosis membrane, characterized in that: The following steps are involved: Step (1): pouring a hexadecene solution onto the surface of a polyamide flat fiber membrane, reacting for 5 to 15 minutes, pouring off the excess solution, washing the surface of the flat fiber membrane, and then pouring a hydroxypropyl-β-cyclodextrin solution onto the surface of a polyamide flat fiber membrane, reacting for 5 to 15 minutes, pouring off the excess solution, washing the surface of the flat fiber membrane, and obtaining a modified polyamide flat fiber membrane; Step (2): The MXene nanosheet dispersion is loaded onto the modified polyamide flat fiber membrane by vacuum filtration and dried to obtain a reverse osmosis membrane.

2. The method for preparing a high-throughput anti-pollution reverse osmosis membrane according to claim 1, characterized in that: The polyamide flat fiber membrane is prepared by the following process: Diamine monomer, diacyl chloride monomer, zinc acetate and solvent are mixed, stirred and reacted under the protection of nitrogen atmosphere to obtain a spinning solution, which is then transferred to a syringe and electrospun on an injection pump to obtain a flat membrane. The flat membrane is heat-treated and then placed in a growth solution for heating reaction for 6 to 10 hours, and taken out to obtain a polyamide flat fiber membrane.

3. The method for preparing a high-throughput anti-pollution reverse osmosis membrane according to claim 1, characterized in that: The MXene nanosheet dispersion is prepared by the following process: S1: Ti3AlC2, LiF and hydrochloric acid solution are mixed, stirred for reaction, centrifuged for the first time, washed, the precipitate after centrifugation is mixed with pure water, ultrasonicated under nitrogen atmosphere protection, centrifuged for the second time, and the upper layer liquid after centrifugation is freeze-dried to obtain MXene nanosheets; S2: Mix MXene nanosheets and buffer solution, and disperse them by ultrasonic to obtain MXene nanosheet dispersion.

4. The method for preparing a high-throughput anti-pollution reverse osmosis membrane according to claim 1, characterized in that: In step (1), the mass ratio of the polyamide flat fiber membrane, the hexadecene solution and the hydroxypropyl-β-cyclodextrin solution is 1:(1-3):(1-3).

5. The method for preparing a high-flux anti-pollution reverse osmosis membrane according to claim 2, characterized in that: The process conditions of electrospinning were: voltage 10-18 kV, feed rate 0.5-0.7 mL / h, syringe needle tip distance to collector 10-16 cm, humidity 10-30%, time 1.5-2 h; The viscosity of the spinning solution is 1~20Pa·s.

6. The method for preparing a high-flux anti-pollution reverse osmosis membrane according to claim 3, characterized in that: In S1, the ratio of Ti3AlC2, LiF and hydrochloric acid solution is (2~4) g: (3~5) g: (100~200) mL; The mass ratio of precipitate to pure water is 1:(10~20).

7. The method for preparing a high-flux anti-pollution reverse osmosis membrane according to claim 2, characterized in that: The process conditions of the stirring reaction are: temperature 0~20℃, time 1~3h, and rotation speed 80~90r / min.

8. The method for preparing a high-flux anti-pollution reverse osmosis membrane according to claim 3, characterized in that: In S1, the process conditions of the first centrifugation are: speed 3000~5000rpm, time 4~6min; The process conditions for the second centrifugation are: rotation speed 8000~10000rpm, time 20~30min.

9. The method for preparing a high-flux anti-pollution reverse osmosis membrane according to claim 1, characterized in that: In step (2), the mass ratio of MXene nanosheet dispersion to modified polyamide flat fiber membrane is 10:(3-8).

10. A high-throughput anti-pollution reverse osmosis membrane, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 9.

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