Enhanced anti-fouling performance through integrated coagulation and membrane co-deposition modification for sustainable water treatment

Membrane fouling remains a significant challenge limiting the widespread use of membrane technology in water treatment, particularly in ultrafiltration (UF) processes. To address this, we proposed a “coagulation + membrane modification” strategy to enhance fouling mitigation. The UF membranes were modified with polydopamine (PDA)-polyethyleneimine (PEI) and zwitterions via co-deposition. We investigated membrane morphology, physicochemical properties, hydrophilicity, permeability, and anti-fouling performance. Results showed that both PDA-PEI and zwitterions produced a more uniform and smoother deposited layer, while only PDA-PEI reduced the membrane contact angle by approximately 43 %, significantly improving surface hydrophilicity. Membranes modified with PDA-PEI exhibited exceptionally high permeability (159.02 L⋅m⁻²⋅h⁻¹) and a high humic acid (HA) rejection rate (91.25 %). Additionally, the PDA-PEI-modified membrane demonstrated excellent antifouling properties, achieving a flux recovery ratio of over 95 % after three cycles. Furthermore, this strategy was applied to actual water treatment, where it outperformed single coagulation or membrane modification alone. The combined approach achieved removal rates of approximately 100 %, 87 %, 92 %, and 84 % for turbidity, TOC, HA, and NOR, respectively, in real water samples. Notably, the strategy showed strong antifouling performance with a specific flux of 0.9 and a flux decline rate of just 10 %, highlighting its considerable potential for improving the fouling resistance of UF processes in water treatment.