Cascading in-situ generation of H2O2 and Fenton-like reaction in photocatalytic composite ultrafiltration membrane for high self-cleaning performance in wastewater treatment

Fouling control is of great significance for polymeric membrane-based wastewater purification and reclamation. Herein, we designed a reactive polysulfone (PSF) ultrafiltration (UF) membrane integrating resorcinol-formaldehyde (RF) resin nanospheres and beta-FeOOH nanoparticles (Fe@RF/PSF) with unique self-cleaning performance. The Fe@RF/PSF membrane with an optimal RF resin and beta-FeOOH loading showed a reasonable water flux (376.3 L m- 2 h-1 bar-1) and high rejection (97.5%) to bovine serum albumin. Besides, the membrane could capture trace amount of cationic dyes in the feed solution via electrostatic attraction. After organic fouling, the permeation flux of the membrane was effectively recovered under visible-light irradiation at neutral pH. We confirmed that the low-bandgap RF resin nanospheres blended in the PSF matrix produced H2O2 in-situ upon absorption of visible light. Then the adjacent beta-FeOOH nanoparticles catalyzed the conversion of the self-supplied H2O2 to center dot OH radicals. The Fe@RF/PSF membrane provided a unique platform to perform cascade reaction for production of center dot OH radicals concentrated in restricted space, which effectively degraded the adsorbed organic foulants. The proposed self-cleaning mechanism that can work under sunlight and ambient condition is expected to simplify and economize the cleaning operations of polymeric UF composite membranes in complex wastewater purification.