High-Performance Forward Osmosis Membranes Used for Treating High-Salinity Oil-Bearing Wastewater

Forward osmosis (FO), which is an emerging osmotic driving membrane separation process, can be directly used in high-salinity oil-bearing (HSOB) wastewater treatment. In this study, the thin film composite (TFC) polyamide FO membranes were fabricated for HSOB wastewater treatment. The impacts of the draw solution (DS) concentration, cross-flow rate, stirring rate, and membrane orientation on membrane performances were researched. The results indicated that the FO operation mode was better to achieve a stable water flux of TFC membranes as 29 L/(m(2) h) under a cross-flow rate of 15 cm/s and 3 M NaCl as the DS, which was 61% higher than the water flux in the unoptimized operating conditions (18 L/(m(2) h)). The rejection rate of salt and oil was 99% and 96%. In addition, the effect of different oil concentrations of HSOB wastewater was studied, and the results showed that FO performed well to treat HSOB wastewater when the oil concentration was <700 mg/L.