Peroxymonosulfate activation by iron-carbon composite derived from coal gasification slag for sulfamethoxazole removal: Performance evaluation and mechanism insight

•Fe-C composite derived from CGS was first prepared for PMS activation.•The catalyst had excellent catalytic ability among the reported metal-C catalysts.•91.1 % of SMX could be degraded within 90 min in the Fe-C composite/PMS system.•Fe species and oxygen-containing functional groups contributed to ROS generation.•Surface-bounded radicals, 1O2 and electron transfer removed 87.8% of SMX.