Catalytic degradation of bisphenol a (BPA) in water by immobilizing silver-loaded graphene oxide (GO-Ag) in ultrafiltration membrane with finger-like structure

Most ultrafiltration (UF) membranes can hardly remove organic pollutants with low molecular weight, like Bisphenol A (BPA). This study effectively addressed the issue by immobilizing the GO-Ag nano-sheet catalyst within the finger-like pores of a polymer UF membrane using bottom cross-flow filtration. The catalytic membrane operated under a low pressure of 0.2 MPa and achieved a remarkable water flux of 368 L/(m²·h). By filtering aqueous substrates with BPA and humic acid (HA), the UF membrane could effectively reject most of the high molecular weight HA (>90.8%). The BPA entered the membrane pores could be effectively decomposed (>99.4%) by the free radicals generated by the peroxydisulfate(PDS)/GO-Ag system. Also, the catalytic membrane exhibits significantly enhanced BPA degradation kinetics, up to 19.6 times higher than those of conventional suspension-based methods. Moreover, the GO-Ag catalytic membrane demonstrates excellent reusability, maintaining almost constant flux after multiple cycles with a flux recovery rate (FRR) of 90.1%. This is attributed to the in-situ degradation of pollutants attached to the membrane by the free radicals. In addition, it is proved that the GO-Ag catalytic membranes show significant antibacterial abilities. In summary, the GO-Ag/PES catalytic membrane offered significant advantages, such as a convenient fabrication process and the integration of membrane separation and advanced oxidation processes (AOPs) in a single step, eliminating pollutants quickly, saving catalysts and oxidants, and minimizing membrane fouling.