Co2SnO4@Co3O4-SnO2 composite for enhanced peroxymonosulfate activation: Catalytic degradation of diclofenac, mechanism and degradation pathways

Abstract

Co2SnO4@Co3O4-SnO2 catalyst was successfully prepared via co-precipitation method. The physico-chemical properties of the resulting powder were determined by X-ray diffraction (XRD), infrared attenuated total reflectance spectroscopy (IR-ATR), N2 adsorption/desorption, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The material was tested for the catalytic degradation of diclofenac (DCF) by activating the peroxymonosulfate (PMS). Several parameters such as the catalyst amount, PMS and DCF concentrations were optimized. The experiment results revealed that Co2SnO4@Co3O4-SnO2-PMS system showed a good catalytic performance. Indeed, DCF was completely degraded within 2 min under optimal conditions. Radical scavenging experimental results showed that singlet oxygen 1O2 was identified as the only reactive species during the catalytic degradation of DCF. Finally, a possible degradation pathway was proposed based on the intermediates identified using liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS).