Functionalized inorganic hydrogel-based membrane for synergistic oil/water separation and catalytic degradation

Abstract

Hydrogel-modified superwetting membranes typically exhibit remarkable resistance to oil fouling during oil/water separation but suffer from unfavorable stability due to the inevitable swelling and exfoliation. A functionalized inorganic hydrogel-based membrane (TIH@PVDF) with satisfactory durability was proposed for the first time to ingeniously integrate excellent anti-oil fouling and high flux recovery (FRR) for efficient oil/water separation. The TIH@PVDF membrane exhibited a high separation efficiency of over 99 % for oil-in-water emulsions (including liquid paraffin, isooctane, and hexadecane). Owing to the synergistic effect of hydration and catalytic ability from inorganic hydrogel, a FRR of 97.9 % was achieved by catalytic regeneration after seven cycles of oil/water separation, outperforming hydraulic cleaning (90.6 %). Most importantly, the TIH@PVDF membrane demonstrates outstanding capability in separating actual oil field-produced water, indicating its potential for practical application. Meanwhile, the existence of metallic elements in the inorganic hydrogel endowed the TIH@PVDF membrane with sufficient active sites to produce O₂^•- and ¹O₂ via peroxymonosulfate (PMS) activation towards organics decomposition. The TIH@PVDF membrane presented a satisfactory removal efficiency (99.1 %) of sulfamethoxazole during a single-pass catalytic separation process. This research may revolutionize the advancement of inorganic hydrogel-based catalytic membranes for oil/water separation and wastewater decontamination.