Redesigning electrochemical-based Fenton processes: An updated review exploring advances and innovative strategies using phenol degradation as key performance indicator

Abstract

The removal of toxic and persistent organic pollutants is one of the major engineering challenges for water treatment. Development of Fenton-based advanced oxidation processes (AOPs) has shown promising results over water remediation control. The present critical review presents a benchmark framework of understanding on the recent advances of such Fenton-based AOPs based on the abatement of phenol as model pollutant, considering articles published in the period 2019–2023. Fundamentals, the effect of operating variables over the degradation and mineralization of phenol waters, and the role of in situ generated oxidizing agents are summarized and analyzed for understanding the competitiveness and niche application of processes such as homogeneous and heterogeneous Fenton, homogeneous photo-Fenton, hybrid heterogeneous photocatalysis/photo-Fenton, homogeneous and heterogeneous electro-Fenton, and photoelectro-Fenton. Especial emphasis is made on strategies designed to overcome the narrow pH limitation to 3.0 of Fenton reaction. A comparative cost analysis of the above homogeneous processes revealed that homogeneous electro-Fenton was the most viable and cost-effective process. The present review shows that phenol can be used as reference to assess the notable impact of recent advances of Fenton-based AOPs.