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CN-117282279-B - High-stability easy-storage low-pressure reverse osmosis membrane and preparation method thereof

CN117282279BCN 117282279 BCN117282279 BCN 117282279BCN-117282279-B

Abstract

The application relates to the field of reverse osmosis membranes, and particularly discloses a high-stability easy-storage low-pressure reverse osmosis membrane and a preparation method thereof, wherein the high-stability easy-storage low-pressure reverse osmosis membrane comprises a polysulfone-based membrane and a polyamide functional layer, the polyamide functional layer is prepared from an aqueous phase containing organic amine substances and an oil phase containing acyl chloride substances through interfacial polycondensation reaction, and the aqueous phase further comprises silane modified amino polyethylene glycol dopamine and an antioxidant; the reverse osmosis membrane provided by the application is modified by chemical crosslinking and an antioxidant adding method is used, so that the poor stability of the low-pressure reverse osmosis membrane during storage is avoided, and the performance of the membrane is reduced after the membrane is placed.

Inventors

  • YANG GUOYONG

Assignees

  • 苏州苏瑞膜纳米科技有限公司

Dates

Publication Date
20260505
Application Date
20230925

Claims (10)

  1. 1. A high-stability easy-storage low-pressure reverse osmosis membrane is characterized by comprising a polysulfone-based membrane and a polyamide functional layer, wherein the polysulfone-based membrane is prepared from a casting solution containing polysulfone, the polyamide functional layer is prepared from an aqueous phase solution containing organic amine aqueous phase monomers and an oil phase solution containing acyl chloride oil phase monomers, and the aqueous phase solution further comprises amino polyethylene glycol dopamine modified by a silane coupling agent.
  2. 2. The high-stability easy-to-store low-pressure reverse osmosis membrane of claim 1, wherein the side of the polysulfone base membrane of the high-stability easy-to-store low-pressure reverse osmosis membrane far away from the polyamide functional layer is further coated with a glycerol moisturizing layer, and the side of the polyamide functional layer far away from the polysulfone base membrane is further coated with a protective layer.
  3. 3. The high-stability easy-to-store low-pressure reverse osmosis membrane according to claim 2, wherein the glycerol moisturizing layer is formed by coating a glycerol solution with a mass percentage of 5-10%, the protective layer is formed by coating a polyvinyl alcohol solution with a trace amount of glycerol, the mass percentage of polyvinyl alcohol in the polyvinyl alcohol solution is 2-5%, the alcoholysis degree of the polyvinyl alcohol is 78-92%, and the addition amount of the trace amount of glycerol is 2-10% of the mass of the polyvinyl alcohol.
  4. 4. The high-stability easy-to-store low-pressure reverse osmosis membrane of claim 1, wherein the silane coupling agent is isocyanatopropyl trimethoxysilane, and the molar ratio of amino polyethylene glycol dopamine to isocyanatopropyl trimethoxysilane is 1 (0.9-1.1).
  5. 5. The high-stability easy-storage low-pressure reverse osmosis membrane of claim 1, wherein the preparation process of the amino polyethylene glycol dopamine modified by the silane coupling agent comprises the steps of adding the silane coupling agent and the amino polyethylene glycol dopamine into an ethanol water solution, mixing, stirring for 15-20 minutes at 70-80 ℃, filtering, and drying to obtain the amino polyethylene glycol dopamine modified by the silane coupling agent.
  6. 6. The high-stability easy-to-store low-pressure reverse osmosis membrane of claim 1, wherein nano silicon dioxide is added into the polysulfone base membrane, and the weight percentage of the nano silicon dioxide is 2-3% based on the total mass of the casting solution.
  7. 7. The high stability easy storage low pressure reverse osmosis membrane of claim 1 wherein said aqueous solution further comprises an antioxidant, a surfactant, a pH adjustor and an acid acceptor, said antioxidant comprising sodium metabisulfite, said surfactant comprising sodium dodecylbenzenesulfonate, said pH adjustor comprising camphorsulfonic acid, said acid acceptor comprising sodium hydroxide.
  8. 8. A method for preparing a high-stability easy-storage low-pressure reverse osmosis membrane according to any one of claims 1 to 7, wherein the method comprises the following steps: S1, preparing a base membrane, namely coating a casting membrane solution on non-woven fabrics, standing, and solidifying in pure water to prepare a polysulfone base membrane; s2, water phase coating, namely coating a water phase solution on the polysulfone base membrane obtained in the S1, and drying to obtain a water phase layer; and S3, oil phase coating, namely coating the oil phase solution on the water phase layer prepared in the step S2, and drying to obtain the reverse osmosis membrane.
  9. 9. The method for preparing a high-stability easy-to-store low-pressure reverse osmosis membrane according to claim 8, further comprising the steps of S4, cleaning the reverse osmosis membrane prepared in S3 with pure water, coating a glycerol moisturizing layer on one side of the polysulfone base membrane far away from the polyamide functional layer, coating a protective layer on one side of the polyamide functional layer far away from the polysulfone base membrane, and drying.
  10. 10. The method for preparing a high-stability easy-storage low-pressure reverse osmosis membrane according to claim 8, wherein the preparation process of the membrane casting solution in S1 is that solid polysulfone, a good solvent, a pore-forming agent and nano silicon dioxide are stirred and mixed, the standing time is 5-15 minutes, the good solvent comprises N, N dimethylformamide, the pore-forming agent comprises ethylene glycol monomethyl ether, the mass percentage of the polysulfone is 12-18% based on the total mass of the membrane casting solution, the mass percentage of the good solvent is 75-85%, the mass percentage of the pore-forming agent is 0.5-10%, The drying temperature in the S2 is 50-80 ℃, the aqueous phase solution comprises 2-10% of organic amine aqueous phase monomer by mass percent and 3-5% of amino polyethylene glycol dopamine modified by the silane coupling agent by mass percent; the drying temperature in the step S3 is 50-80 ℃, and the oil phase solution contains 0.1-1.0% of acyl chloride oil phase monomers by mass percent; The temperature of the solidified pure water solidifying liquid in the pure water in the step S1 is 10-15 ℃.

Description

High-stability easy-storage low-pressure reverse osmosis membrane and preparation method thereof Technical Field The application relates to a reverse osmosis membrane, in particular to a high-stability easy-storage low-pressure reverse osmosis membrane and a preparation method thereof. Background The membrane separation technology has the characteristics of energy conservation, environmental protection, simple process, easy control and the like as well as the functions of separation, concentration and purification, and has been rapidly developed in recent years. The low-pressure reverse osmosis membrane is operated under the pressure lower than 2.0Mpa, consumes low energy, is popular in the market, and is particularly suitable for ultra-low-pressure reverse osmosis membranes, the operating pressure is 0.5-1.0Mpa, the energy consumption is lower, and the popularization and the application of the membrane are facilitated. At present, the preparation method of the polyamide reverse osmosis membrane is an interfacial polymerization method, wherein a layer of aqueous phase solution with a certain proportion is uniformly spread on the surface of a polysulfone membrane serving as a supporting layer, the excessive aqueous phase solution is removed, then an oil phase solution is poured into the membrane surface, and the interfacial polymerization reaction is carried out, so that the polyamide reverse osmosis membrane can be obtained after a period of reaction. Under the environment of high temperature and high humidity, the oxidation substances and the acidic substances in the air are more active, so that the possibility of unstable membranes is increased, and meanwhile, the polyamide functional layer can be physically damaged in the use process, so that the service life is reduced. Therefore, the storage condition and the transportation condition of the membrane are extremely harsh in the actual production, and the product is greatly puzzled. Particularly, when the film is stored under high temperature and high humidity in summer, air leakage is easily caused when the film is rolled into a film element, the desalination rate is reduced, the storage stability is poor, and the service performance is unqualified when the film is seriously stored. How to greatly improve the strength of the reverse osmosis membrane, improve the storage stability and ensure the flux and the desalination rate of the reverse osmosis membrane in a high-temperature and high-humidity environment is an urgent problem to be solved. Disclosure of Invention The application provides a high-stability easy-storage low-pressure reverse osmosis membrane and a preparation method thereof, aiming at solving the problems of high flux and high desalination rate performance of the low-pressure reverse osmosis membrane when being stored in a high-temperature high-humidity environment. In a first aspect, the application provides a high-stability easy-storage low-pressure reverse osmosis membrane, which comprises a polysulfone-based membrane and a polyamide functional layer, wherein the polysulfone-based membrane is prepared from a casting solution containing polysulfone, the polyamide functional layer is prepared from an aqueous phase solution containing an organic amine aqueous phase monomer and an oil phase solution containing an acyl chloride oil phase monomer, and the aqueous phase solution further comprises amino polyethylene glycol dopamine modified by a silane coupling agent. By adopting the scheme, polysulfone is used as a base membrane, a polyamide functional layer is obtained on one side of the polysulfone base membrane through interfacial polycondensation by a water phase containing organic amine substances and an oil phase containing acyl chloride substances, after the amino polyethylene glycol dopamine modified by the silane coupling agent is added into the reverse osmosis membrane, in the process of film formation by aqueous solution, the migration performance of the silane coupling agent promotes the migration of the amino polyethylene glycol dopamine phase membrane surface treated by the silane coupling agent, meanwhile, the regular long chain polyethylene glycol is freely stretched in the system, when the water phase diffuses towards the oil phase, the amino polyethylene glycol dopamine treated by the silane coupling agent crosses in a structure generated by crosslinking, so that the integral strength of the reverse osmosis membrane is improved, and simultaneously, phenolic hydroxyl groups in the amino polyethylene glycol dopamine treated by the silane coupling agent can react with acyl chloride to participate in interfacial polymerization, so that the compactness and the integral strength of the reverse osmosis membrane are improved, and the separation performance and strength of the reverse osmosis membrane are further improved. And the silane coupling agent modified amino polyethylene glycol dopamine migrating to the base membrane keeps pa