Ce/N @BC prepared based on plant metallurgy strategy: A novel activator of peroxymonosulfate for the degradation of sulfamethoxazole

Abstract

A novel carbon catalyst was created based on plant metallurgy strategy for organic pollutants removal. Plants rich in CeO₂ NPs in water were used as carbon precursors and pyrolyzed with urea to obtain Ce/N co-doped carbon catalysts, which were used in the degradation of sulfamethoxazole (SMX) by active peroxymonosulfate (PMS). The results showed that the Ce/N @BC/PMS system achieved to 94.5% degradation of SMX in 40 min at a rate constant of 0.0602 cm^-1. The activation center of PMS is widely dispersed Ce oxide nanocrystals, and CeO₂ NPs promote the formation of oxygen centered PFR with enhanced catalytic ability and longer half-life. In addition, N-doping facilitates the transfer of π-electrons within the sp2 carbon of biochar, increasing active sites and thus improving PMS activation efficiency. The degradation process was contributed to by both radical and non-radical activation mechanisms including ¹O₂ and direct electron transfer, with O₂^•- serving as ¹O₂'s precursor. Through the DFT calculations, LC-MS and toxicological analyses, the degradation pathway of pollutants and the toxicity changes throughout the entire degradation process were further revealed, indicating that the degradation of SMX could effectively reduce ecological toxicity.

Keywords: Advanced oxidation processes; Biochar composites; CeO(2) NPs; Persulfate activation; Phyto-metallurgical.