High-flux renewable chlorine-resistant reverse osmosis composite membrane and preparation method thereof

By grafting diaminodiphenylamine onto the surface of the reverse osmosis membrane, a reversible redox polyaniline layer was constructed, which solved the problem of the reverse osmosis membrane being susceptible to active chlorine attack, improved high flux and chlorine resistance, and ensured the membrane's regenerability and separation performance.

CN120815459APending Publication Date: 2025-10-21VONTRON TECH CO LTD
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Patent Information

Application Number
CN202410435030.9
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2024-04-11
Publication Date
2025-10-21

AI Technical Summary

Technical Problem

Existing reverse osmosis membranes are susceptible to active chlorine attack during use, leading to performance degradation, and it is difficult to improve water flux and chlorine resistance while maintaining a high desalination rate.

Method used

By grafting diaminodiphenylamine onto the surface of a reverse osmosis membrane, a high-density polyaniline-modified layer is constructed using its reversible redox properties with active chlorine. This protects the polyamide separation layer, improves the membrane's chlorine resistance, and enables the grafted membrane to be regenerated through Na2S2O3 reduction.

Benefits of technology

A high-flux, regenerable, and chlorine-resistant reverse osmosis composite membrane has been developed, maintaining good water separation performance and desalination rate, and its performance can be restored after multiple chlorination treatments.

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Abstract

The invention belongs to the technical field of reverse osmosis membranes, and particularly relates to a high-flux reproducible chlorine-resistant reverse osmosis composite membrane and a preparation method thereof.Monomer 3, 5-diamino-1, 2, 4-triazole is added into a water-phase solution, functional amino and imino groups of the monomer react with acyl chloride groups, and the high-flux reproducible chlorine-resistant reverse osmosis composite membrane is prepared by adjusting the structure of a polyamide layer; the separation performance of the membrane can be improved while the water flux of the membrane is not obviously reduced. According to the reverse osmosis composite membrane preliminarily obtained through interfacial polymerization reaction, aniline dimer diaminodiphenylamine is adopted as a modification material, and chemical grafting modification of the membrane surface is carried out on a polyamide composite membrane. The characteristic that the redox potential of a secondary amine group on diaminodiphenylamine is lower than that of an amide group on a polyamide polymer is utilized, the secondary amine group can serve as a sacrificial group to react with active chlorine preferentially, protection of a polyamide separation layer is achieved, and therefore the chlorine resistance of the composite membrane is improved. In addition, diaminodiphenylamine has the same reversible redox characteristic as aniline, and reversible regeneration of chlorine resistance of the grafted membrane can be realized through Na2S2O3 reduction; therefore, the high-flux reproducible chlorine-resistant reverse osmosis composite membrane disclosed by the invention is a reverse osmosis composite membrane based on aniline dimer surface modification, and has the characteristics of high flux, reproducibility, excellent chlorine resistance, good water separation performance, better hydrophilicity and salt rejection rate.
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