A high performance of thin film composite based on dextran substrate for effective removal of heavy metal ions

Abstract

A high performance thin film composite forward osmosis (FO) membrane with dextran as additive in support layer has been developed for effective heavy metal ions removal for the first time. The proposed FO process consists of a thin film composite (TFC) FO membrane made from interfacial polymerization on a high porous and hydrophillic polysulfone embedded dextran support to minimize the internal concentration polarization effect. The created substrates were characterized in terms of surface chemistry and morphology prior to performance evaluation. The support layer incorporating with dextran exhibited lower contact angle and high porosity as an ideal support layer for FO process. Moreover, the ridge-and-valley structure of TFC membranes made with support layers containing larger openings, long finger-like voids and macrovoids was more noticeable for the active layers, according to high-resolution scanning electron microscopy. The removal of metals were demonstrated, water fluxes were around 13 L/m².h and rejection were above 95 %. The performance of developed membrane was then showed greater water flux and rejection in comparison to the commercial TFC.