Catalytic activation of persulfate by nanoscale zero-valent iron-derived supported boron-doped porous carbon for bisphenol A degradation

Abstract

Abstract In this study, boron modified carbon materials (BCs) with porous structures and high surface areas were firstly synthesized employing coffee grounds, sodium bicarbonate and boric acid as precursors, afterward, nanoscale zero-valent iron (nZVI) and BCs composites (denoted as nZVI@BCs) were synthesized through reduction of FeSO4 by NaBH4 along with stirring. The catalytic performance of the nZVI@BCs was evaluated for the degradation of bisphenol A (BPA) via persulfate (PS) activation. In comparison with nZVI@Cs/PS, nZVI@BCs/PS could greatly promote the degradation and mineralization of BPA. Further analysis exhibited that our system existed radical pathway and non-radical pathway for BPA removal. On the one hand, electron spin resonance and radical quenching studies represented that •OH, SO4•− and O2•− were mainly produced in the nZVI@BCs/PS system, which were responsible for the degradation of BPA. On the other hand, the open circuit voltages of nZVI@BCs and nZVI@Cs in different systems indicated that non-radical pathway still existed in our system. PS could grab the unstable unpaired electron on nZVI@BCs to form a carbon materials surface-confined complex ([nZVI@BCs]*) with a high redox potential, then accelerate BPA removal efficiency via electron transfer. Furthermore, the performances and mechanisms for BPA degradation were examined by PS activation with nZVI@BCs composites at various conditions including dosages of nZVI@BCs, BPA and PS, initially pH value, temperature, common anions and humid acid. This study provides a novel insight for development of high-performance carbon catalysts toward environmental remediation.