Enhanced performance and recyclability for peroxymonosulfate activation via g-C3N4 supported CoFe layer double oxide

Abstract

CoFe layered double oxide (CoFe LDO) anchored on g-C3N4 was prepared by mixing appropriate amounts of CoFe layer double hydroxide and melamine at moderate synthesis temperatures. The resulting CoFe LDO/g-C3N4 composite has superior properties in peroxymonosulfate (PMS) activation, resulting in remarkable activity in catalyzing paracetamol degradation. It has been able to degrade 10 mg/L paracetamol in less than 10 min in darkness by using 0.2 g/L catalyst and 0.5 mM PMS dosages. The effects of PMS and catalyst dosage, initial pH and coexisting anions were also investigated. Negligible cation leaching, enhanced reusability and enhanced stability make CoFe LDO/g-C3N4 an attractive compound for environmental pollution abatement. The influence of g-C3N4 on lowering Co and Fe valence states in CoFe LDO compounds by covalent stimulates the oxidant radical (SO4− and OH) production and concomitantly paracetamol degradation. Electro magnetic resonance experiments and a so-called chemical probe were used to identify SO4− as the dominant radical in the degradation processes. Interestingly, X-ray absorption spectroscopy and electrochemical measurements revealed the existence of a second contributing mechanism, based on a pure electron transfer process from the pollutant to PMS mediated by the catalyzer. These findings, pioneer a new method for the mechanism of coupling radical and electron transfer processes that act synergistically to promote paracetamol degradation in scarcely 10 min in darkness.