Na/Cu-Doping Engineering of Carbon Nitride for High-Performance Visible-Light Degradation of Iopamidol

Visible-light-driven photocatalytic generation of hydroxyl radicals provides a sustainable pathway for the photodegradation of emerging contaminants. Particularly, carbon nitride (g-C₃N₄) is a promising photocatalyst for the removal of emerging contaminants; however, it suffers from a limited surface area and a bandgap that restricts its visible-light photocatalytic efficiency. To overcome these limitations, this study presents a novel copper-sodium codoped graphitic carbon nitride (NaCu-g-C₃N₄) photocatalyst with enhanced visible-light photocatalytic activity tested for the degradation of Iopamidol, a persistent and toxic pollutant resistant to conventional wastewater treatment plants. The codoping of Na and Cu was strategically employed to reduce the bandgap energy, enhance visible-light absorption, and increase the surface area, thereby improving the photocatalytic activity of carbon nitride. When combined with the oxidizing agent H₂O₂, the system accelerated the formation of oxidizing radicals. The synergy of NaCu-g-C₃N₄ and H₂O₂ yielded 82.3% degradation of Iopamidol within 120 min under visible light at pH 3, marking the highest and first successful reported visible-light-driven degradation of Iopamidol. These findings highlight the potential of NaCu-g-C₃N₄ as a cost-effective semiconductor photocatalyst for the efficient and sustainable removal of persistent pollutants.