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-C3N4(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-C3N4(KPS) was successfully doped with carboxyl groups on g-C3N4. Besides, center dot OH, O-1(2), center dot O-2(-) and h(+) were generated in the photocatalytic system of g-C3N4(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.

Automated summary

The paper presents a novel method for preparing metal-free carboxyl modified graphite phase carbon nitride (g-C3N4(KPS)) using potassium persulfate (KPS) as an oxidizing agent, and applies it to activate peroxymonosulfate (PMS) for the degradation of organic compound carbamazepine (CBZ) under solar radiation. The study reveals the green, low-cost, and facile nature of the process, and proposes a possible photocatalytic degradation pathway for CBZ.