Enhanced resistance to organic fouling in a surface-modified reverse osmosis desalination membrane

Membrane surface modification with the aim of lowering foulant to surface affinity, has recently gained considerable attention. In this article, we report improved performance (permeate flux, salt rejection, and resistance to alginate fouling) of surface-modified reverse osmosis (RO) membranes, under cross-flow filtration conditions. The surface of RO membranes was modified by amphiphilic hydroxethyl methacrylate-co-perfluorodecyl acrylate (HEMA-co-PFDA) copolymer films. The amphiphilic coatings were deposited via an all-dry and solventless vapor deposition technique, termed as initiated chemical vapor deposition. Scanning electron microscopy revealed that a dense and continuous layer of alginate formed on the surface of the unmodified membranes, whereas foulant deposition on the surface-modified membranes was found to be more sporadic and discontinuous. The coatings were found stable even after 6 h of exposure to sodium alginate at higher pressure (800 psi), as evidenced by ATR-FTIR analysis of the post-fouled membranes.