Highly Permeable Thin-Film Composite Forward Osmosis Membrane Based on Carbon Nanotube Hollow Fiber Scaffold with Electrically Enhanced Fouling Resistance

摘要

Forward osmosis (FO) is an emerging approach in water treatment, but its application is restricted by severe internal concentration polarization (ICP) and low flux. In this work, a self-sustained carbon nanotube hollow fiber scaffold supported polyamide thin film composite (CNT TFC-FO) membrane was first proposed with high porosity, good hydrophilicity and excellent electro-conductivity. It showed a specific structure parameter as low as 126 μm, suggesting its weakened ICP. Against a pure water feed using 2.0 M NaCl draw solution, its fluxes were 4.7 and 3.6 times as high as those of the commercial cellulose triacetate TFC-FO membrane in the FO and pressure retarded osmosis (PRO) modes, respectively. Meanwhile, the membrane showed excellent electrically assisted resistance to organic and microbial fouling. Its flux was improved by about 50% during oil–water simulation separation under 2.0 V voltage. These results indicate that the CNT TFC-FO membrane opens up a frontier for stably and effectively recycling potable water from electrochemical FO process.