Rational design of efficient metal-free catalysts for peroxymonosulfate activation: Selective degradation of organic contaminants via a dual nonradical reaction pathway.

Designing efficient and low-cost catalysts to activate peroxymonosulfate (PMS) to rapidly degrade organic contaminants is important for the practical applications of the advanced oxidation process. Herein, inspired by the water absorption process of the baby diaper, we design nitrogen-doped porous carbon network catalysts (N-PCNs) for peroxymonosulfate activate to degrade recalcitrant organic pollutants. The resulting product called nitrogen-doped porous carbon networks carbonized at 800 °C (N-PCN8) exhibits enhanced adsorption and catalytic activity due to its large specific surface area (1137.7 m2 g-1), highly graphitic degree, and high graphite N content (50.3%).4-CP (0.02 g/L) was completely degraded in 30 min by using N-PCN8 (0.2 g/L) and PMS (0.2 g/L). The catalytic system is efficient over a wide pH range (3-9) and shows strong resistance to interference with inorganic anions (Cl-, HCO3-, CO32-). Several aromatic pollutants, including 4-CP, BA, NB, HBA, CBZ, and BPA, are used as target pollutants to further evaluate the oxidative capacity of the system, and the degradation rate were 100%, 19.5%, 3.5%,5 5.7%, 79% and 100%, respectively. Results suggest that the system is selective for pollutants, and singlet oxygen oxidation and mediated electron transfer effects are the main causes of 4-CP degradation.