Activation of peroxymonosulfate by LaCO3OH coupled with N, S co-doped graphene for levofloxacin degradation

There is currently great potential in peroxymonosulfate (PMS) activation by metal-based materials for contaminant treatment. However, secondary environmental damage from common transition metals is often unavoidable. Rare earth metals with high energy level, multi-electron configuration and unique 4f orbital can be used as an electron transfer bridge to reduce interfacial energy loss and promote electron transfer, which were incorporated the catalyst to activate PMS. In this study, calcination and hydrothermal methods were combined to fabricate LaCO3OH in combination with N, S co-doped graphene (LCOH/GNS), which exhibited efficient levofloxacin (LVX) degradation. The results indicated that the LVX removal efficiency reached 89.6 %, and the La3+ leaching was as low as 1.2 mg/L. LaCO3OH (LCOH) was first used for PMS activation and showed excellent degradation properties and reduced ecotoxicity. Doping the graphene matrix with N and S enhances the adsorption of PMS, increases electron transfer and reduces leaching of metal ions, thus promoting the interaction and reaction between LCOH and PMS. As confirmed by radical quenching tests and EPR technique, multiple oxidative pathways may be involved in the degradation process. This paper presented an innovative approach to the rational design of rare earth metal-based carbon catalysts, and it was expected that LCOH/GNS-PMS would prove to be a promising technology for degrading antibiotics in wastewater treatment.