Periodate activation with polyaniline-derived carbon for bisphenol A degradation: Insight into the roles of nitrogen dopants and non-radical species formation

Abstract

Periodate-based advanced oxidation processes (PI-AOPs) activated by carbon catalysts have shown promising application prospects in the removal of emerging contaminants. Herein, a series of N-doped carbon catalysts (NC) were prepared by in-situ pyrolysis of N-containing polymers (polyaniline) to unveil the potential mechanism of N dopants on PI activation. The optimized sample NC700 showed a satisfying degradation performance, achieving 100 % removal of bisphenol A (BPA) at a concentration of 10 mg/L within 90 min in the presence of 0.1 mM PI. The impacts of various N types on PI activation were systematically investigated by dynamic fitting and density functional theory computations. These analyses highlighted the crucial role of graphitic N configuration on carbon surface, which exhibited the highest adsorption energy and a positive correlation with the normalized degradation efficiency. The chemical quenching experiments and electrochemical experiments confirmed that the BPA oxidation mechanism was primarily mediated electron transfer by [NC-PI]* complex, with singlet oxygen (1O2) /superoxide radicals (O2•–) playing a supplementary role. In situ ATR-SERAS measurement strengthened the understanding of PI activation by carbon catalyst based on electron transfer pathway. Owing to the non-radical oxidation mechanism, the NC/PI system had a broad pH adaptability and great anti-interference ability against typical wastewater components. This study provides mechanistic insights into the carbon-driven PI activation process for wastewater treatment, advancing the practical application of PI-AOPs.