Graphene oxide-silver nanosheet-incorporated polyamide thin-film composite membranes for antifouling and antibacterial action against Escherichia coli and bovine serum albumin

Abstract Biofouling leads to degradation of membrane performance characteristics, including permeability, selectivity, and long-term stability. In this study, silver-doped graphene oxide (GO) was employed as a nanoadditive to enhance the biofouling resistance of thin-film nanocomposite (TFN) membranes via interfacial polymerization. Ag functionalization on GO sheets was carried out by a reduction reaction. Electron microscopy, Raman spectroscopy, and X-ray diffraction analyses were conducted to evaluate Ag attachment on GO. According to zeta potential and contact angle measurements as well as atomic force microscopy results, GO-Ag-incorporated TFN membranes showed a high negative charge, hydrophilicity, and a smooth surface. Bovine serum albumin protein and Escherichia coli (E. coli) were used as model fouling agents to demonstrate the antifouling characteristics of the membranes. The TFN membrane containing 80 ppm of GO-Ag had a high water flux recovery ratio (89%) and low irreversible resistance (10%) after hydraulic washing. The biofouling resistance of the membranes was further studied by a colony-counting method, while bacterial adhesion was analyzed by spinning disk confocal microscope imaging. The TFN membrane prepared with 80 ppm GO-Ag reduced 86% of viable E. coli cells in bacterial suspensions, with only slight bacterial adherence on the membrane surface.