Electrochemical regeneration of carbon-based adsorbents: a review of regeneration mechanisms, reactors, and future prospects

The reusability of carbon-based adsorbents determines the techno-economics of the adsorption technology. Various methods, which include conventional thermal and biological regeneration and the subsequently developed new methods are continuously being investigated and engineered. Among these, electrochemical regeneration is promising due to its energy efficiency, selectivity, cost-effectiveness, and environmental compatibility. Electrochemical regeneration covers various regeneration mechanisms and operational methods, but till now, they have not been properly classified or deeply reviewed. In this review, the basic mechanisms of electrochemical regeneration are summarized, followed by a review of various electrochemical regeneration methods with a detailed comparison in terms of regeneration efficiency. Electrochemical reactors are then given special attention because they are significant for the scaling-up of individual regeneration methods. Additionally, the cycling performances of carbon adsorbents are assessed based on an analysis of the physicochemical property changes of carbon adsorbents. Finally, future trends of electrochemical regeneration methods are discussed.