Application of Fenton-like systems for wastewater detoxification

Abstract

Industrialization has led to severe environmental challenges, primarily the contamination of water bodies with persistent organic pollutants (POPs) such as pharmaceuticals, synthetic dyes, and toxic organic compounds. Conventional treatment methods, including biological processes and coagulation, often prove insufficient for the complete degradation of these chemically stable substances. This review systematically examines the application of Fenton-like systems as a promising advanced oxidation process (AOP) for industrial wastewater detoxification. Specifically, the review aims to compare degradation efficiencies across three priority pollutant classes—toxic organic compounds, synthetic dyes, and pharmaceutical residues - identify the catalytic and operational factors governing process performance, and evaluate techno-economic constraints relevant to industrial scaling. The operational principles and catalytic cycles involving reactive hydroxyl radicals (•OH) are detailed, highlighting the transition from classical homogeneous reactions to more versatile heterogeneous systems. Recent advances demonstrate that utilizing transition metals (Cu, Mn, Ni) and novel materials like metal-organic frameworks (MOFs) and bimetallic oxides allows these processes to operate effectively at near-neutral pH, overcoming the strict acidic limitations of traditional Fenton chemistry. Furthermore, the integration of physical stimuli - such as ultraviolet radiation (photo-Fenton), electricity (electro-Fenton), and ultrasound (sono-Fenton) - is shown to significantly enhance radical generation and mineralization rates for complex molecules. The review provides a comparative analysis of treatment efficiencies, achieving removal rates often exceeding 95% for various toxic groups. Finally, technical and economic constraints, including sludge formation and energy intensity, are discussed alongside prospects for scaling these technologies for sustainable industrial application.