Utilizing cobalt-doped materials as heterogeneous catalysts to activate peroxymonosulfate for organic pollutant degradation: a critical review

Abstract

As a new class of water treatment technologies, redox-based advanced oxidation processes (AOP) involving peroxymonosulfate (PMS) activation show wide application prospect in the water treatment. Accordingly, cobalt-doped materials have proven to be some of the most effective and efficient heterogeneous catalysts for activating PMS to degrade a variety of recalcitrant organic pollutants. In this critical review, cobalt-doped catalysts are reasonably classified according to the types of solid substrates used, and their catalytic performances in the degradation of various organic pollutants in wastewater are summarized. The catalytic mechanisms of cobalt-doped catalysts for activating PMS are discussed in detail, where the effect of the substrate on the overall catalytic activity is emphasized. In addition, we also discuss the durability and cobalt leaching of the cobalt-doped catalysts for the degradation of organic pollutants. This review shows that cobalt-doped catalysts have promising potential in water treatment based on the promotion or synergistic effect of the substrate, reduced cobalt dosage, and their stable structure. It also provides a perspective on future research on cobalt-based catalyst/PMS systems in practical environmental cleanup.