Synthesis of AgCl mineralized thin film composite polyamide membranes to enhance performance and antifouling properties in forward osmosis

This is the first report using an alternate soaking process (ASP) to mineralize the surfaces of thin film composite (TFC) polyamide membranes with silver chloride (AgCl) for forward osmosis (FO). Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analysis confirmed even distribution of AgCl particles on the top of the membrane surfaces. Surface roughness, contact angle, and zeta potential measurements show that the AgCl mineralized membranes have smoother, more hydrophilic, and more negatively charged surfaces than unmodified membranes. Under FO operation (with deionized water feed and 1 M NaCl draw), we found that the mineralized membranes exhibit higher salt rejection and water flux than the original membranes. Fouling experiments with bovine serum albumin (BSA) show that the mineralized membranes have lower water flux decline ratios in BSA aqueous solution and higher water flux recovery ratios after simple hydraulic washing than unmodified TFC membranes.