Recent trends and developments in Fenton processes for industrial wastewater treatment - A critical review

This study reviews the recent developments in the application of Fenton processes in real industrial wastewater treatment, focusing on heterogeneous catalysts and catalyst regeneration/reuse. This article presents the features, inherent advantages or drawbacks, and primary experimental results obtained on established and emerging Fenton processes, highlighting the course of innovations and current scenario in a research field that has recently undergone rapid transition. Therefore, a comprehensive literature survey was conducted to review studies published over the last decade dealing with application of Fenton processes to industrial wastewater treatment. The research in this field is primarily focused on discovering or synthesizing new materials to substitute conventional iron salt Fenton catalysts and/or regenerate and reuse the spent catalyst, in contrast to optimizing the application of existing materials. Hence, the emphasis is on producing reusable materials, transitioning from linear to circular economy. Some of the major challenges identified herein include analyzing or improving heterogeneous catalyst lifetime, determining the predominant pathway of heterogeneous and homogeneous catalysis to pollutant degradation, and defining the best layout to incorporate Fenton processes into full-scale treatment plants, particularly its coupling with biological treatment.