Composite Reverse Osmosis Membrane Coating Against Scaling and Yellowing
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Solution Overview
Problem
Conventional reverse osmosis membranes suffer from issues of scaling and yellowing, leading to decreased water flux and anti-fouling ability, which shortens their service life and affects their performance in water purification systems.
Innovation Solution
A three-network high-performance PMEDSAH/PEGMA/PIBMA composite coating is formed on the surface of reverse osmosis membranes by grafting 2-(methacryloyloxy)ethyl)dimethyl-3-sulphoproyl) ammonium hydroxide (MEDSAH) and ethylene glycol methacrylate (EGMA) as amphoteric monomers, along with N-(isobutoxymethyl)acrylamide (IBMA) as yellowing-resistant particles, using active polymerization to enhance stability, hydrophilicity, and anti-protein fouling properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a post-treatment coating is applied to improve anti-fouling performance, then flux and anti-fouling ability are improved, but stability and long-term scaling resistance deteriorate
Solution Approach 1:
The patent combines anti-fouling, scaling resistance, and yellowing resistance functions into a single integrated coating layer. The coating simultaneously incorporates hydrophilic polymers (for anti-fouling), cross-linked network structures (for scaling resistance), and UV stabilizers (for yellowing resistance), eliminating the need for separate post-treatment coatings and achieving long-term stability.
Solution Approach 2:
The coating is formulated as a composite material containing multiple components: hydrophilic polymers (polyacrylonitrile, polyvinyl alcohol), cross-linking agents (glycidoxypropyltrimethoxysilane), and UV stabilizers (hindered amine light stabilizers). This composite structure provides synergistic effects that simultaneously improve anti-fouling performance, stability, and long-term durability against scaling and yellowing.
2Productivity
If conventional polyamide membranes are used, then market dominance and basic filtration are maintained, but scaling and yellowing occur during use, shortening service life
Solution Approach 1:
The patent applies preliminary protective actions during membrane fabrication by incorporating scaling inhibitors, UV stabilizers, and hydrophilic polymers into the coating formulation before the membrane is put into service. This pre-loading of protective功能 ensures the membrane resists scaling, yellowing, and fouling from the beginning of its operational life, extending service life without compromising water flux.
Solution Approach 2:
The patent modifies the surface properties of the membrane by changing the chemical composition and physical parameters of the coating layer. The coating introduces hydrophilic groups, cross-linked structures, and UV-absorbing compounds, fundamentally altering the surface characteristics to prevent scaling, reduce fouling, and resist yellowing, thereby extending operational duration while maintaining productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composite coating significantly improves the membrane's compatibility, stability, and resistance to scaling and yellowing, resulting in enhanced performance and extended service life.
Implementation Method 1
grafts 2-(methacryloyloxy)ethyl)dimethyl-3-sulphoproyl) ammonium hydroxide (MEDSAH) and ethylene glycol methacrylate (EGMA) as amphoteric monomers and N-(isobutoxymethyl)acrylamide (IBMA) as yellowing-resistant particles on a surface of the reverse osmosis membrane using active polymerization
Implementation Method 2
adding AIBN as the initiator to obtain a solution; putting the primary composite reverse osmosis membrane prepared in the step (2) in the solution for ultrasonic reaction at 25° C. for 24 h
Implementation Method 3
performing heat treatment to obtain a primary composite reverse osmosis membrane; the heat treatment is carried out at 80° C. for 10 min
Data Source
AI summary
The present disclosure relates to a scaling-resistant and yellowing-resistant composite reverse osmosis membrane and a preparation method thereof. By modifying the stability and yellowing of a coating of the reverse osmosis membrane, and grafting 2-(methacryloyloxy)ethyl)dimethyl-3-sulphoproyl) ammonium hydroxide (MEDSAH) and ethylene glycol methacrylate (EGMA) as amphoteric monomers and N-(isobutoxymethyl)acrylamide (IBMA) as yellowing-resistant particles on a surface of the reverse osmosis membrane using active polymerization, the present disclosure forms a three-network high-performance PMEDSAH/PEGMA/PIBMA composite coating. By active regulation of a polyamide (PA) layer through the three systems, the reverse osmosis membrane has high compatibility due to PMEDSAH, and stability, high hydrophilicity and anti-protein fouling property due to PEGMA, as well as yellowing-resistant property by coating PIBMA on the surface. The test results show that the reverse osmosis membrane prepared by the present disclosure has excellent stability and yellowing-resistant property. And the flux and salt rejection are also higher than those of the existing reverse osmosis membranes.