The Photocatalytic Oxidation of As(III) Enhanced by Surface Alkalinized g-C3N4

A new, facile, and efficient way to prepare alkalinized g-C3N4 is presented. We calcined a mixture of KCl and melamine to obtain g-C3N4, whose in-plane structure was K+ doped so that alkalinized samples could be obtained by treatment with different concentrations of KOH. The different samples were used to oxidize As(III) in both visible light and natural light. The sample treated with 10 mol/L KOH showed the highest efficiency, converting all As(III) into As(V) within 120 min in both visible light and natural light, as the oxidative capacity of the As(III) in the alkalinized samples was significantly higher than that of the original samples. K+ doping improved the electron transport capacity of the samples, while the alkalinized samples could destroy their edge structures, so as to improve the separation efficiency of the photogenerated carrier. The experiment confirmed that alkalinized g-C3N4 significantly improves the oxidation ability of As(III) and plays an important role in the photocatalytic treatment of refractory nonmetallic ions.