Integration of oxalic acid chelation and Fenton process for synergistic relaxation-oxidation of persistent gel-like fouling of ceramic nanofiltration membranes

Ceramic nanofiltration (NF) is a newly-developed technology for water recycling, but still limited to pilot-scale applications. Lacking efficient and eco-friendly strategies cleaning ceramic NF membrane impedes its scaling-up in industries. Forward flush, backwash acidic/caustic are not enough. In this work, novel oxalic acid-aided Fenton process was proposed synergistic relaxation/oxidation of persistent Ca2+-mediated gel-like fouling membrane. A reactive catalyst layer online pre-coated on top the via pressure-driven cross-flow pre-filtration Fe3O4 hydrosols. The simulated by alginate presence Ca2+ ions. Results show that loading could be readily tuned from 0.16 1.34 g m?2 altering permeate flux during pre-coating. permeability loss due pre-coating minimal (<10%). combination acid chelation Fenton-based oxidation resulted high recovery (85.07%) iron-oxide membrane, whereas single treatment hydrogen peroxide (H2O2) or inefficient. This effect attributed relaxation gel acid/Ca2+ chelation, which presumably facilitated H2O2 diffusion at Fe3O4/foulant interface. maintained stable initial normalized fluxes (83.33–90.15%) through acid/H2O2 over five cycles, with no need refreshing pre-coat. Additionally, leaching iron pre-coat suppressed combination, owing shielding competitive sorption onto surface. Overall, method, demonstrated study, provides new insights into improving reactivity processes hybrid catalytic membranes control.