Graphitic nitride-catalyzed advanced oxidation processes (AOPs) for landfill leachate treatment: A mini review

Landfill leachate poses significant risks to public health via the release of high-toxicity contaminants, including refractory organic compounds, ammonia-nitrogen compounds, and heavy metals. Significant efforts have been made to develop useful methods for leachate disposition and treatment. Advanced oxidation processes (AOPs) are one of the most promising methods, because they can rapidly degrade diverse pollutants and significantly improve the biodegradability of leachate. Graphitic carbon nitride (g-C₃N₄), a fascinating conjugated polymer, has become a hot topic in AOP research due to its metal-free benefits and high photosensitivity. Thus, combining AOPs with g-C₃N₄ achieves excellent degradation of refractory pollutants in leachate. Since the composition of leachate is complex in the practical conditions, the information reported by current studies of using g-C₃N₄ as a remediator is still incomplete and fragmented. Thus, in this review, the recent status of leachate treatment and approaches for its disposal has been summarized and some conclusions have been drawn. In addition, a brief introduction to g-C₃N₄ and its application in AOPs for leachate treatment have been critically discussed and with its future outlook assessed. Although the development of g-C₃N₄ in AOPs for leachate treatment is highly efficient and practical, comprehensive study about its application and technology expansion is urgently needed, based on the complex operating conditions. Perspectives on the treatment of leachate using g-C₃N₄-AOPs are also included. The information and perspectives provided in this review will provide guidance and novel understanding to accelerate the development of g-C₃N₄-based AOPs for leachate treatment.