Anaerobic environment-induced efficient degradation of chloroquine phosphate: Insights into the role of metal-free C3N4 nanotube in visible light-driven peroxymonosulfate activation

•C3N4NT achieved PMS activation and CQP degradation under anaerobic environment.•Competitive adsorption and consumption behaviors of dissolved O2 and PMS were revealed.•Anaerobic environment allowed a greater number of photogenerated charges to activate PMS.•Anaerobic process overcame interference from matrices and maintained degradation.