Fabrication of antifouling reverse osmosis membranes by incorporating zwitterionic colloids nanoparticles for brackish water desalination

Antifouling is important for RO membranes. Taking advantage of the reaction between hydroxyl groups on zwitterionic colloid nanoparticles (ZCPs) and acyl chloride group, ZCPs with tuned chemical structures were added into m-phenylenediamine aqueous solution to prepare thin-film nanocomposite membranes (ZPMs) via interfacial polymerization in this study. The incorporation of ZCPs tailored the membrane surface morphology and chemical properties, which were characterized by SEM, AFM, WCA, FTIR and XPS. Meanwhile, the effect on RO membranes separation and antifouling performances were systematically evaluated. In comparison with pristine membranes, the values of WCA decreased which means the hydrophilicity of membranes surface enhanced due to the existence of ZCPs, endowing the membrane with advanced water flux (37.3 L.m(-2).h(-1)) when operate with 2000 ppm NaCl aqueous solution at 25 degrees C under 1.5 MPa. In order to evaluate the antifouling properties, the filtration with different types of model foulants were operated. When feed solution containing tannic acid, sodium alginate or sodium dodecyl sulfonate respectively as model foulants, ZPMs exhibited low water flux reduction and high water flux recovery after cleaning due to increased hydrophilicity and surface smoothness. Therefore, the ZPMs with improved separation and antifouling performances are promising candidates for practical application in brackish water desalination.