Metal-free carboxyl modified g-C3N4 for enhancing photocatalytic degradation activity of organic pollutants through peroxymonosulfate activation in wastewater under solar radiation

The peroxymonosulfate-based advanced oxidation process (PMS-AOP) is widely studied as a powerful technology for organic pollutants degradation in wastewater. In this paper, an inventive one-step method utilizing potassium persulfate (KPS) as an oxidizing agent was put forward to prepare metal-free carboxyl modified graphite phase carbon nitride (g-C 3 N 4 (KPS)), which was applied to significantly activate PMS for the degradation of organic compound carbamazepine (CBZ) under solar radiation. Without strong acids and organic solvents , the process was considered green, low-cost, and facile. The characterizations showed that g-C 3 N 4 (KPS) was successfully doped with carboxyl groups on g-C 3 N 4 . Besides, •OH, 1 O 2 , •O 2 − and h + were generated in the photocatalytic system of g-C 3 N 4 (KPS)/PMS. As a result, a possible CBZ photocatalytic degradation pathway was proposed. This work not only discovered a novel method of activating PMS but also offered valuable insights for the preparation of efficient metal-free catalysts for wastewater environmental governance.