Mechanistic insights into activation of peracetic acid by sludge biogas residue biochar for efficient sulfamethoxazole degradation in aqueous solution

The application of peracetic acid (PAA) in the advanced oxidation process has been demonstrated to be an effective approach for treating aqueous organic pollutants. In this study, it is the first time that biogas residue biochar (BRBC) derived from sludge anaerobic digestion plants was prepared and used as a PAA activator for sulfamethoxazole (SMX) degradation. The optimal SMX removal could achieve 92 % within 120 min under acidic conditions. The SMX degradation was slightly enhanced in the presence of Cl^-, while it could be inhibited by HCO₃^-. Quenching experiment and EPR analysis demonstrated that both radical and non-radical processes contributed to SMX degradation. ECOSAR analysis showed a significant reduction in intermediate toxicity. Meanwhile, BRBC700 exhibited excellent reusability and stability even in real water matrices. The study presented an innovative approach for biogas residue application and provided a novel pretreatment for SMX-containing wastewater for further biological treatment method after simple acid-base regulation.