Efficient persulfate activation catalyzed by pyridinic N, COH, and thiophene S on N,S-co-doped carbon for nonradical sulfamethoxazole degradation: Identification of active sites and mechanisms

•N,S-co-doped carbonaceous persulfate activators are synthesized.•Complete SMX removal and 80% mineralization rate are achieved.•N/S atomic ratio largely affects the catalytic performance.•Pyridinic N, COH, and thiophene S act as the active sites.•Degradation of SMX is mediated by nonradical 1O2.