Improvement of the antifouling and antibacterial properties of polyethersulfone membrane by incorporating the natural additives collagen and green tea

This study focuses on the fabrication of low-fouling polyethersulfone ultrafiltration (PES UF) membranes using collagen (COL) and polyphenon 60 from green tea (PGT) as additives. The casting solution was prepared by dissolving COL and PGT in PES solution with N-methyl-2-pyrrolidone as solvent. A series of characterizations and performance examinations, including scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDX) mapping, Fourier transform infrared spectroscopy (FTIR), contact angle (CA) measurement, pure water flux (PWF), porosity, antifouling test using bovine serum albumin (BSA) and humic acid (HA) solution, antibacterial test using E. coli and S. mutans, were conducted. The addition of COL and PGT not only significantly increased PWF, water uptake, porosity, and hydrophilicity but also increased solute rejection and flux recovery. The membrane prepared with the addition of COL (1 wt%) and PGT (3 wt%) demonstrated PWF of 353.9 L/m2. h, water uptake of 238.8%, porosity of 75.1%, CA of 36.9°, and solute rejection of 98.5%. Further, the flux recovery reached 85.08% and 78.78% after anti fouling examination using BSA and HA solutions, respectively. The COL/PGT/PES membrane also demonstrated superior dynamic antibacterial filtration with 93.5% bacteria removal of E. coli and highly efficient antibacterial activity above ∼98% against both E. coli and S. mutans. Thus, the COL/PGT/PES membrane exhibited significant antifouling and antibacterial properties and better performance than the nascent PES UF membrane.