When treating wastewater, traditional AOPs mainly break down pollutants into harmless substances completely with radical chain reactions. However, the long-term use of these methods brings problems in sustainable development. They use too much energy and produce large amounts of carbon emissions. Researchers have carried out recent studies on oxidation-polymerization ways. These studies show that polymerization reactions work better than mineralization processes. They can remove organic pollutants effectively. They also cut down energy use greatly and help realize the reuse of resources. This paper summarizes the working principles and newest progress of polymerization reactions. These reactions are started by different active substances. The content includes radical ways like organic and inorganic radicals. It also includes non-radical ways such as high-valent metal oxides, electron transfer processes, complexes and singlet oxygen. Additionally, this paper puts forward methods to improve polymerization reactions. These methods come from two aspects. One is radical ways including concentration synergistic regulation, redox potential and nanoconfinement. The other is non-radical ways including electron regulation, microstructure regulation and composite carrier design. Finally, this paper talks about the difficulties and limits of polymerization ways in removing organic pollutants and lists future research directions in this area. It aims to offer reference and theoretical help for the later use of oxidative polymerization ways in resource recovery.

Metal sulfides are abundant in nature. They also have excellent catalytic qualities and tunable electronic structures. These characteristics make them extremely attractive materials advanced oxidation processes (AOPs) in wastewater treatment. In this review, the relationship between structure and property in monometallic and bimetallic sulfides is examined in detail. The key point is to introduce their working mode - activating peroxymonosulfate (PMS), peroxydisulfate (PDS) and hydrogen peroxide to generate reactive oxygen species. The key methods for improving catalytic performance were elaborated in detail. This includes the rational design of bimetallic sulfides, introduction of sulfur vacancies, non-metal doping and in-situ regeneration techniques. These methods can adjust the electronic configuration, expose active sites and accelerate the metal redox cycling effectively. This greatly enhances the degradation efficiency and maintains the stability of the catalyst. This review also studies the environmental factors that affect catalytic performance. It points out future directions for developing metal sulfide-based catalysts. These directions are for their practical use in water remediation.

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.