Insight into the performance and mechanism of peroxymonosulfate activation by B, N co-doped hierarchical porous carbon for phenol degradation

Abstract

A series of boron and nitrogen co-doped hierarchical porous carbon materials (BNC) were prepared via a facile one-step calcination process, and the catalytic performance of BNC on PMS activation for phenol removal was investigated. BNC-1 exhibited the optimal catalytic performance with a phenol degradation efficiency of 99.6% within 30 min. B, N co-doping strategy improved the specific surface areas (SSA) and total pore volumes (TPV) of carbon catalysts, providing them with abundant active sites, among which graphitic N and BC3 were identified as critical catalytic sites for PMS activation. Quenching tests, electron paramagnetic resonance (EPR) and electrochemical experiments demonstrated that singlet oxygen (1O2) was the dominant active species while surface-bound sulfate radical (SO4·-) played an inferior role in the BNC-1/PMS/Phenol system, and the role of hydroxyl radical (·OH), superoxide radical (O2·-) and surface electron transport cannot be ignored either. The coexistence of radical and non-radical oxidation processes made BNC-1/PMS system have excellent acid-base tolerance (pH=3–11), anti-interference ability and pollutant mineralization performance (68.3% of TOC removal within 30 min). This study presented a high-efficiency and environment-friendly B, N co-doped metal-free catalyst for pollutants degradation via PMS activation and provided an in-depth research for the mechanism of PMS activation by BNC.