Nanoconfined catalytic membranes for EfOM fouling mitigation: An intelligent “pore-centric” cleaning strategy

Abstract

This study investigated the effectiveness of the nanoconfined catalytic membrane (NCCM), fabricated by nitrogen-doped carbon nanotubes (NCNT) incorporated with graphene oxide membrane (NCNT@GO-M), in mitigating fouling caused by effluent organic matter (EfOM). Compared to conventional catalytic membranes (NRCM) that lack precise spatial design and prepared with only NCNT, NCCM exhibits a unique advantage by preferentially retaining and adsorbing protein-like substances in EfOM during the fouling formation process, forming a cake layer that effectively mitigates pore blockage from irreversible foulants. Furthermore, the ordered nanoconfined structure of NCCM facilitates an intelligent “pore-centric” hierarchical degradation strategy based on the molecular size of EfOM, preferentially removing irreversible foulants caused by fulvic acid-like and low molecular weight protein-like substances. The results demonstrated effective preservation of catalytic sites by the NCCM’s advanced nanoconfined configuration and a 1.6-fold increase in the mass transfer rate of peroxymonosulfate (PMS) compared to NRCM, synergistically promoting hydroxyl radical (•OH) enrichment, resulting in rapid EfOM degradation kinetics. Additionally, chemical cleaning almost completely eliminated irreversible fouling, restoring the NCCM to near its original flux. Overall, this study sheds light on the fouling mitigation mechanisms of NCCM, aiding their tailored design and application in targeted wastewater treatment.