Incorporation of porous materials in forward osmosis membrane for increased water recovery from waste streams

Abstract

Forward osmosis (FO) is a membrane separation process that involves an osmotic pressure-driven, semi-permeable membrane to selectively separate water from waste streams. Increased water flux and salt removal characterize an ideal FO membrane. In contrast to the first-developed symmetric cellulose triacetate (CTA) membrane, the thin film composite (TFC) membrane had a higher water flow and a lower reverse salt flux. The incorporation of porous and non-porous nano-sized particles in the membrane structure has improved TFC performance even further. The TFC-FO membrane was created in this study by incorporating porous ZIF-8 MOF into the polyethersulphone (PES) support layer. Interfacial polymerization of chitosan (CS) biopolymer and trimesoyl chloride (TMC) produced the thin separation layer. The porous MOFs provided additional water pathways. The water wettability of the separation layer was also improved by CS-TMC polymerization. In comparison to the bare membrane, the water fluxes of the ZIF-8@FO membrane improved by 2.8 times. The newly developed FO membrane was found effective for use in sewage and wastewater treatment.