Fabrication of BaSO4-based mineralized thin-film composite polysulfone/polyamide membranes for enhanced performance in a forward osmosis process

摘要

Novel BaSO4-based mineralized thin-film composites (TFC) as forward osmosis (FO) membranes were fabricated through depositing barium sulfate on the surface of the prepared polysulfone/polyamide (PSf/PA) membranes by adopting an approach named surface mineralization. BaSO4 particles were deposited by an alternate soaking process (ASP) with aqueous solutions of barium chloride (BaCl2) and sodium sulfate (Na2SO4), separately. Membranes with different mineralization degrees were prepared by changing the number of ASP cycles. The mineralized TFC PSf/PA FO membranes were characterized by a variety of methods in accordance with membranes structure and surface properties. It turned out that the mineral coating made of BaSO4 particles was evenly distributed on the membrane surface and the existence of this coating made the membrane surface became more hydrophilic and negatively charged after mineralization. The FO performances of the mineralized TFC membranes were also tested and compared with the original PSf/PA membrane and the commercial CTA-W FO membrane with pure water as the feed solution and a 1 M NaCl solution as the draw solution. The mineralized TFC PSf/PA membranes displayed better water permeability and salt rejection than the original PSf/PA membrane and the commercial FO membrane. The results revealed that mineralized TFC PSf/PA membranes showed great potential for further development of FO applications.