Azido-group functionalized graphene oxide/polysulfone mixed matrix ultrafiltration membrane with enhanced interfacial compatibility for efficient water and wastewater treatment

Bio-fouling of membranes caused by microorganisms seriously limited the development of membrane technology in practical applications. Design and synthesis of antifouling and antibacterial membranes with high quality are of paramount importance. In this study, we report a facile and safe method of extended Mitsunobu reaction (EMR)-freeze drying (FD) method to achieve oxygen-containing azido functionalized GO (AGO) nanosheets and synthesize novel azido-group functionalized graphene/polysulfone mixed matrix ultrafiltration membranes with enhanced permselective, antifouling and antibacterial property. Unlike reported thermochemical or chemical reactions to modify GO nanosheets, GO nanosheets were functionalized at low temperature which effectively prevented the decomposition of structural frame of pristine GO materials and the self-stacking phenomenon. Because of strong interactions between oxygen-containing AGO nanosheets and polymer matrices, high dispersity and interfacial compatibility were obtained in polysulfone membranes, resulting in sharp decrease of interfacial defects. Different kinds of techniques include SEM, ATR-FTIR, XPS, XRD, TEM and EDX were used to investigate the structure and morphology of AGO nanosheets and blended membranes, and cross-flow filtration experiments, anti-fouling and antibacterial test were applied to predict the behavior of hybrid membranes. High performance AGO/PSF mixed matrix membranes with excellent anti-fouling ability were successfully synthesized, which exhibited pure water flux as large as 245.1 L m−2h−1 with satisfactory rejection of 95.8% for BSA. Moreover, the prepared membranes displayed good antibacterial activity against E. coli and S. aureus in long-term duration.