Chemical oxidation and reduction technologies for water and wastewater treatment: Current status, challenges, and future directions

Abstract

Chemical oxidation and reduction technologies have been extensively explored as effective approaches for degrading recalcitrant contaminants in water and wastewater, with several methods already adopted commercially and implemented in real-world applications. This review presents a comprehensive evaluation of the current progress, obstacles, and future prospects of principal redox-based processes, encompassing ozoneand UV-based oxidation, persulfate activation, zero-valent iron reduction, noble metal-catalyzed reduction, electrochemical methods, and photocatalysis. These processes utilize highly reactive oxidizing and reducing agents, which facilitate broad-spectrum contaminant elimination due to robust redox potentials and adaptability to various water matrices. Nevertheless, widespread adoption on a large-scale is still limited by considerable energy consumption, elevated material expenses, and the production of undesirable secondary byproducts. Through systematic analysis of advantages and drawbacks, this review identifies strategies to advance chemical redox technologies toward scalable, energy-efficient, and robust water treatment systems. Ultimately, chemical oxidation and reduction methods demonstrate significant promise for supplementing or exceeding conventional treatment solutions, thus supporting the preservation of clean and safe water resources for generations to come. © 2025 Korean Society of Environmental Engineers.