A collaboration between the RPE Lille site of Infranalytics and the team of Rabah Boukherroub of the IEMN has made it possible to determine the radical species involved in the degradation of organic molecules present in wastewater. In the presence of a nanocomposite catalyst based on cobalt sulphide and graphene oxide (CoS-rGO), an oxidizing molecule, the PMS is activated into two radical species, •OH and SO4•-. The combination of the EPR spin trap technique and radical scavenging measurements with ethanol or/and tert-butanol, confirmed that the radical species responsible for the decomposition of organic molecules such as pentachlorophenol and rhodamine B, was the sulfate radicals. These results were published in Journal of Environmental Chemical Engineering.

Picture : EPR spectra of CoS-rGO and CoS-rGO/PMS and structure of rhodamine B. The presence of the CoS-rGO catalyst and PMS strongly improves the formation of the radicals responsible for the degradation of rhodamine B.