FeOCl/MIL-88A heterojunction modified PVDF membrane for enhanced photo-Fenton catalytic degradation and antifouling performance in wastewater treatment

FeOCl/MIL-88A composites were used to modify the surface of polyvinylidene fluoride (PVDF) membranes. • Simultaneous high pollutant degradation (94% RhB, 91% MB) and remarkable antifouling with FRR increased from 61% to 93%. • Low Fe leaching (0.102 mg/L) and sustained performance over 5 cycles confirm excellent reusability and safety. • The heterojunction between FeOCl and MIL-88A facilitates charge separation and generates ·OH and·O 2 − . Catalytic membranes fabricated by surface loading of active materials have shown great potential for antifouling improvement. This study investigated a photo-Fenton synergistic membrane separation process by fabricating a FeOCl/MIL-88A composite on the surface of PVDF membranes, which markedly enhanced the membrane performance. The modified membrane (FM-3) maintained high pure water flux (518.2 L/m 2 ·h·bar) and porosity (80%) while exhibiting hydrophilicity (contact angle of 8°). Compared with the pristine membrane, FM-3 achieved a substantially higher HA rejection (78%) with only a minor loss of permeability, alleviating the conventional permeability–rejection trade-off. Under visible-light-driven photo-Fenton conditions, FM-3 demonstrated high degradation efficiencies of 94% for RhB and 91% for MB, with stable performance over 5 cycles. Moreover, the membrane demonstrated remarkable antifouling performance, with a flux recovery ratio (FRR) of 93% and an irreversible fouling rate (R ir ) of only 7%. Finally, a possible membrane antifouling mechanism is proposed:·OH and·O 2 − are the primary active species in the catalytic process. The formed heterojunction facilitates efficient charge separation and promotes the Fe 3+ /Fe 2+ cycle. DFT calculations further confirmed the electron transfer direction from FeOCl to MIL-88A, providing theoretical support for the proposed heterojunction mechanism. This work provides a novel and effective approach for designing high-performance catalytic membranes with synergistic separation and anti-fouling functions for sustainable wastewater treatment. Download: Download high-res image (145KB) Download: Download full-size image