Development of a g-C3N4-based photocatalysis-self-Fenton system for efficient degradation and mineralization of organic pollutants

Abstract

Photocatalytic water treatment holds great promise for addressing global challenges associated with energy shortage and water scarcity. However, despite decades of research, its practical implementation remains constrained by the limited efficiency in generating and utilizing hydroxyl radicals (^·OH). To this end, this study develops a photocatalysis-self-Fenton system based on graphitic carbon nitride (g-C₃N₄). By introducing P heteroatoms into the g-C₃N₄ matrix, we enhance O₂ adsorption, while the incorporation of cyano groups improves H⁺ adsorption (both of which favor H₂O₂ generation) and prevents the generated H₂O₂ from decomposing into ^·OH on the catalyst surface. This system boosts the steady-state concentration of ^·OH by approximately 42 times compared to photocatalytic system, while the homogeneous generation of ^·OH further enhances its utilization. As a result, it enables the complete degradation of 2,4-Dichlorophenol in only 20 min under visible light, with a mineralization rate of 71.21 %. Additionally, this system demonstrates broad applicability, achieving removal efficiencies exceeding 90 % for various typical organic pollutants (4-chlorophenol, bisphenol A, norfloxacin, ciprofloxacin, and sulfadiazine). Furthermore, its durability across multiple cycles underscores its potential for practical water treatment applications.