Advances in research on ultra-low oxidant consumption: Fenton and Fenton-like systems

Against the backdrop of green sustainable development, Fenton and Fenton-like reaction systems serve as crucial advanced water treatment technologies. A key research focus lies in exploring reaction pathways and mechanisms that minimize peroxide consumption while ensuring efficient degradation and detoxification of organic pollutants. In this review, we systematically outline strategies for achieving ultra-low peroxide consumption based on three key aspects of the reaction system: (i) Regulating non-radical oxidation processes mediated by ¹O₂, high-valent metal species, and electron transfer process, leveraging their higher selectivity and longer lifetimes compared to radicals (e.g., SO₄^•− and HO^•) to effectively reduce peroxide usage; (ii) Dynamically modulating reaction pathways and efficiently generating/utilizing non-radical reactive species through multiscale catalyst regulation and optimization; (iii) Guiding the precise design and economical selection of catalysts and AOPs based on organic pollutant substrate characteristics. Finally, this paper thoroughly examines key challenges and development directions for non-radical oxidation systems in practical applications. It aims to advance the engineering transformation of these technologies for real-world wastewater treatment, emphasizing their significant potential and application prospects as low-peroxide-consumption water treatment strategies. This review seeks to provide critical references and theoretical support for developing efficient and economical technologies for organic pollutant removal.