Surface modification of polyamide membrane with silane compounds and its effect on the performance of reverse osmosis

摘要

Thin-film-composite (TFC) membranes based on aromatic polyamides (PAs) are widely used in commercial high-performance reverse osmosis (RO) for the desalination of seawater and brackish water. In this study, surface modification of PA-based RO membranes was performed using silane compounds with various functional groups to improve the performance of membranes (permeate flux and salt rejection). Lab-scale tests demonstrated that the salt rejection of PA-based RO membranes coated with TMOHES (trimethoxy[2-(7-oxabicyclo[4.1.0] hept-3-yl) ethyl] silane) was barely improved despite the hydrophobicity of its epoxy groups, but the permeate flux was significantly improved by using AEAP ([3-(2-aminoethylamin) propyl] trimethoxysilane) due to its hydrophilic amino groups. Based on the results, RO membranes treated with 2.0% AEAP concentration showed the best performance due to their highly improved permeate flux and competitive salt rejection.