Adsorption of cerium (III) by HKUST-1 metal-organic framework from aqueous solution

Cerium is an important rare earth element (REE), which can be used for many high-tech applications. From the industrial and environmental viewpoints, it is imperative to recover Ce3+ ions from aqueous solution. Herein, HKUST-1 metal-organic framework (MOF) was applied for adsorption and recovery of Ce3+ from aqueous solution. HKUST-1 showed a high adsorption efficiency and remarkable capacity of 353 mg/g at pH = 6. The isotherm, kinetics, effect of pH value and adsorption mechanism of the Ce3+ adsorption process were also studied. The results showed that the adsorption process fitted the Langmuir adsorption model, and the pseudo-second-order model described the kinetics well. The mechanism and reusability in Ce3+ adsorption were systematically investigated by various characterization techniques, suggesting the possible ion exchange between Ce3+ and Cu2+ and the formation of CeO covalent bonding. This work opens up a new way for Ce3+ recovery from water.