A review on approaches for addressing the limitations of Fenton oxidation for recalcitrant wastewater treatment

Fenton oxidation is an effective technology for the degradation of recalcitrant organic pollutants. However, conventional Fenton oxidation possesses some drawbacks such as the requirement of acidic pH condition, production of iron sludge and requirement of high chemical inputs. Strategies such as heterogeneous Fenton, fluidized bed Fenton, use of chelating agents and in-situ production of Fenton's reagent have been studied as possible solutions to these limitations. Although there have been reviews on the fundamentals and applications of Fenton oxidation, a review with focus on the limitations of Fenton oxidation and their possible solutions is lacking. Here, we review the limitations of Fenton oxidation and the recent strategies toward addressing them. For each approach, fundamentals and applications in the removal of recalcitrant pollutants are reviewed. Heterogeneous Fenton process is the most widely investigated due to the progress in catalysis. Fluidized bed Fenton process could lower sludge generation and enhance process performance. Chelating agents are used to conduct homogeneous Fenton at circumneutral pH, though the potential detrimental effect of some chelating agents remains a source of concern. In situ production of Fenton's reagent through bioelectrochemical technology (bioelectro-Fenton) is emerging as a possible strategy to reduce the cost associated with Fenton's reagent. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.