Enhanced degradation of organic compounds through the interfacial transfer of electrons in the presence of phosphate and Nitrogen-cobalt doped graphitic carbon

Abstract

Peroxymonosulfate (PMS) has been activated for the generation of reactive oxygen species by nitrogen-doped carbonaceous material. However, the influence of phosphate on the degradation performance has not been reported. In this study, phosphate ions accelerate PMS decomposition and degradation of target organic compounds such as carbamazepine, atrazine, sulfamethoxazole, and benzoic acid. It was revealed that the physical mixture of phosphate with Co and N doped graphitic carbon (GcN/Co) demonstrates the occurrence of P C, P N, and P O - C bonds. Essentially, the graphitic N or graphitic N P increased in the presence of phosphate. This was correlated with the lower electrical transfer resistance, improved electrical conductivity, and higher electron morbidity confirmed by different electrochemical tests. Moreover, due to the strong buffering capacity of phosphate at neutral pH, bicarbonate was used to confirm the negligible influence of pH. The presence of phosphate helps to recover the scavenging effect of Cl^- but has no effect on the presence of HCO₃^- and CO₃^2-. Nevertheless, GcN/Co demonstrates good reusability for three reaction cycles, however, in order to maintain a high catalytic performance phosphate needs to be replenished after each cycle.

Keywords: Co and N doped graphitic carbon; Electron transfer; Graphitic N P; Peroxymonosulfate; Phosphate.