Exploring the electrosorption selectivity and recovery of indium ions with capacitive deionization in acidic solution

High-efficiency recycling technology for endangered elements effectively mitigates the risk of resource shortages and promises the sustainability of supply chains, which is significant to the industry. In this study, an activated carbon (AC)-based capacitive deionization (CDI) for the selective electrosorption and recovery of indium ions (In3+) from acidic aqueous solution is proposed. The effects of applied voltage, pH, and initial concentration of indium were investigated to optimize the operation parameters for In3+ electrosorption. The results of cyclic voltammetry and the galvanostatic charge/discharge measurements indicate that the AC electrode shows good capability for the electrosorption of In3+ based on electrical double-layer capacitance. As demonstrated, In3+ can be successfully removed by CDI without deposition when the pH