Regulation of micro-structure and surface property of SWRO membrane via introducing albumin into polyamide layer for improving permselectivity

Abstract

The concerned trade-off effect between water permeability and permselectivity hinders further improvement of the performance based on dense polymeric membranes. Here, seawater reverse osmosis (SWRO) membranes with higher water-salt permselectivity and water permeability were prepared by introducing albumin concentrated and crystallized from chicken egg white (EW) into aqueous solution before interfacial polymerization (IP) to regulate the micro-structure and surface property of the aromatic polyamide layers. Due to the hydrophilic nature and its multi-functional groups, EW albumin could disperse homogeneously in aqueous solution during the interfacial polymerization process. The deposited EW albumin on polysulfone (PSf) substrate could also increase the surface charge as well as its hydrophilicity. Due to the higher and more vertical leaf-like structures, together with the rougher surfaces and more hydrophilic surface, the water flux of db-0.1 membrane increased by 21.29 % compared to the original db-0 membrane, which reached 49.66 L·m−2·h−1. Meanwhile, because of the higher cross-linking degree and the more negatively charged property, db-0.1 membrane which exhibited the best water permeability also showed the best NaCl rejection of 99.66 %. It provides new sights on simultaneous regulation of micro-structure and surface property of SWRO membranes for improving water permeability and permselectivity via a facile incorporation procedure.