Recent advances in application of graphitic carbon nitride-based catalysts for degrading organic contaminants in water through advanced oxidation processes beyond photocatalysis: A critical review

Advanced oxidation processes (AOPs) have attracted much interest in the field of water treatment owing to their high removal efficiency for refractory organic contaminants. Graphitic carbon nitride (g-C3N4)-based catalysts with high performance and cost effectiveness are promising heterogeneous catalysts for AOPs. Most research on g-C3N4-based catalysts focuses on photocatalytic oxidation, but increasingly researchers are paying attention to the application of g-C3N4-based catalysts in other AOPs beyond photocatalysis. This review aims to concisely highlight recent state-of-the-art progress of g-C3N4-based catalysts in AOPs beyond photocatalysis. Emphasis is made on the application of g-C3N4-based catalysts in three classical AOPs including Fenton-based processes, catalytic ozonation and persulfates activation. The catalytic performance and involved mechanism of g-C3N4-based catalysts in these AOPs are discussed in detail. Meanwhile, the effect of water chemistry including pH, water temperature, natural organic matter, inorganic anions and dissolved oxygen on the catalytic performance of g-C3N4-based catalysts are summarized. Moreover, the reusability, stability and toxicity of g-C3N4-based catalysts in water treatment are also mentioned. Lastly, perspectives on the major challenges and opportunities of g-C3N4-based catalysts in these AOPs are proposed for better developments in the future research.