Green β-cyclodextrin nanosponges for the efficient adsorption of light rare earth elements: Cerium and lanthanum

During the past decades, the removal and recovery of Lanthanum (La) and cerium (Ce) have attracted considerable interest owing to their importance in several industrial processes. In the present work, green nanosponge adsorbents have been synthesized from a local and economic source of β-cyclodextrin (β-CD), and applied for the first time to La and Ce ion recovery from aqueous solutions. A statistical physics model has been used to analyze adsorption data. This material has shown high adsorption capacities of 625.34 and 773.29 mg g−1 for Ce and La, respectively. Furthermore, a temperature of 298 K has been identified as the best condition to remove these elements from aqueous solutions. Furthermore, DFT simulations have been performed to identify the nature of functional groups involved in removing these rare earth elements. Assessments of the adsorbent regeneration and recycling capacities have also been determined, showing that β-CD nanosponges remain stable and effective for La and Ce adsorption over three desorption-adsorption cycles. Hence, this green, economic, and reusable biomaterial has great potential for recovering light rare earth elements from water. Finally, this study provides new insights for analyzing the adsorption mechanisms of Ce and La under various experimental conditions.