Heterogeneous cobalt-based catalysts for boosting peroxymonosulfate activation: A review on cobalt-ion leaching inhibition strategies

Abstract

Cobalt (Co)-ion leaching is one of the most challenging issues associated with the application of heterogeneous Cobalt (Co)-based catalysts such as peroxymonosulfate (PMS) activators for the removal of organic pollutants. Excessive Co-ions threaten human health, and their leaching mitigates the possibility for efficient reusability of the material and leads to increased handling costs. Hence, the development of highly efficient and stable heterogeneous Co-based catalysts with low Co-ion leaching is essential for future industrial applications. This review summarises the strategies employed in recent years to mitigate or suppress metal-ion leaching from heterogeneous Co-based catalysts. The main approaches, including morphology and structure regulation, surface modification engineering, composition optimisation, and carrier immobilisation, are discussed. Analyses of the operational mechanisms, advantages, and limitations of each strategy are presented. Finally, to realize the practical applications of heterogeneous Co-based PMS systems, existing challenges, and future research prospects are discussed, providing a reference for the design of multiphase Co-based catalysts.