Biochar with self-doped N to activate peroxymonosulfate for bisphenol-A degradation via electron transfer mechanism: The active edge graphitic N site

Environmental endocrine disruptors, represented by bisphenol A (BPA), have been widely detected in the environment, bringing potential health risks to human beings. Nitrogen-containing biocarbon catalyst can activate peroxymonosulfate (PMS) to degrade BPA in water, but its active sites remain opaque. Herein, in this work, nitrogen-containing biochar, i.e., C-Nedge, enriched with graphitic-N defects at the edges was prepared by one-pot co-pyrolysis of chitosan and potassium carbonate. The results showed that the C-Nedge/PMS system can effectively degrade 98% of BPA (50 mg/L). The electron transfer based non-radical oxidation mechanism was responsible for BPA degradation. Edge graphitic-N doping endows biochar with strong electron transfer ability. The catalyst had good recovery and reuse performance. This catalytic oxidation was also feasible for other refractory pollutants removal and worked well for treating practical wastewater. This work may provide valuable information in unraveling the N doping configuration-activity relationship during activating PMS by biochar.