Covalent organic frameworks doped with manganese-metal organic framework for peroxymonosulfate activation

Abstract

A novel N, O modified Mn3O4@porous carbon catalyst (NOC-Mn3O4) was prepared by direct carbonization using the manganese-metal organic framework (Mn-MOF) and covalent organic framework (COF) as precursors to activate peroxymonosulfate (PMS) for the degradation of bisphenol A (BPA) and rhodamine B (RhB). Benefiting from the N and O co-doping of COF, larger specific surface area, faster electron transfer and Mn cycling, the optimum 1NOC-Mn3O4 could significantly improve the degradation performance of BPA and RhB (92.1% and 96.9% within 30 min) as compared to C-Mn3O4 without COF doping. In addition, 1NOC-Mn3O4 showed good reusability and strong anti-interference ability. Radical quenching experiments, X-ray photoelectron spectroscopy (XPS), Electron paramagnetic resonance spectrometer (EPR) and electrochemical tests showed that the 1NOC-Mn3O4/PMS system degraded BPA and RhB by both radical and non-radical pathways. Moreover, the possible degradation pathways of BPA and RhB were proposed by liquid chromatography-mass spectrometry (LC-MS). Except for that, the toxicity of BPA, RhB and their intermediates were evaluated. This study opens up a new prospect for the design of COF-doped PMS catalysts.