A tandem dual-pathway non-radical water purification simultaneously induced by single-molecule peroxymonosulfate with a catalyst of coexisting Cu single atoms and Fe3C nanoparticles

Abstract

The non-radical pathways of persulfate (PMS/PS)-based heterogeneous advanced oxidation processes offer effective means for treating complex water matrices. However, the large-scale application is hindered by the increased input costs and substantial accumulation of SO42–. Therefore, it is crucial to develop novel pathways for efficient PMS/PS activation. Here, we construct a CuSA/Fe3C-NC catalyst with Cu single atoms (SAs) and Fe3C nanoparticles (NPs) co-anchored on a carbon support. The improved d-band centers of Cu and Fe elements optimize the PMS adsorption and activation. Unlike previous studies, the electron acceptor PMS in electron transfer process is not be converted to SO42– but rather to singlet oxygen (1O2) via superoxide radicals (O2•–). A tandem dual-pathway non-radical oxidation system induced by a single-molecule PMS leads to higher PMS utilization. Under extremely low catalyst and PMS dosage conditions (catalyst dosage = 0.04 g/L, PMS dosage = 0.2 mmol/L), CuSA/Fe3C-NC + PMS system can rapidly remove bisphenol A within 30 min and achieve a mineralization rate of 85 %. This work provides strong support for the rational design of catalyst structures to achieve low-input and high-efficiency water purification processes.