Honeycomb-like holey Co3O4 membrane triggered peroxymonosulfate activation for rapid degradation of organic contaminants

Heterogeneous advanced oxidation processes (AOPs) are commonly employed for the degradation of recalcitrant contaminants, however, practical application of heterogeneous AOPs has been limited by their low activation efficiency and inefficient utilization of radicals. Herein, this study demonstrates for the first time that 2D honeycomb-like holey membranes assembled by Co3O4 nanosheets, serve as an excellent activator for peroxymonosulfate (PMS) and aid in rapid pollutant removal. The Co3O4 membrane achieved 100% target pollutant ranitidine removal and a membrane retention time of only ~385 ms with the degradation rate 3-5 orders of magnitude faster than that achieved by conventional heterogeneous catalysis. Ranitidine degradation was maintained at >90% for 13 h of continuous-flow operation at a high flux of 176 L m-2 h-1 bar-1. Furthermore, the Co3O4 membrane could also effectively degrade several recalcitrant pollutants, including pharmaceutical personal care products, phenols, and dyes. SO4•- and •OH were identified as the primary reactive oxygen species in the Co3O4 membrane/PMS system, with Co providing the active site for PMS activation. This strategy of membrane-based AOP treatment offers helpful guidance for the design of other efficient heterogeneous catalytic systems and presents a novel approach to overcoming the limitations of conventional heterogeneous catalysis.