Preparation and evaluation of composite hybrid nanomaterials for rare-earth elements separation and recovery

Abstract

A new technology is necessary to representing an entire process of separation and recovery of rare-earth lanthanides (Ln(III)) elements to keep the eco-system for stable industrial growth. In this study, novel hard and soft donor organic ligand containing mesoporous composite hybrid nanomaterial (CHM) was fabricated for specific ytterbium (Yb(III)) ion separation and recovery in sustainable method. The Yb(III) ion was selected based on the Ln(III) intra-series separation behavior in the solid-liquid separation approach. The present approach was based on basic research of individual process steps with the stable complexation mechanism according to the O- and N-donor coordination. The usual bond distance between Yb-O and Yb-N was 2.206 and 2.847 Å, which was clarified that the O-atom was hardly donating than the N-atom of the synthesized organic ligand. However, both atoms were coordinating with Yb(III) ions to clarifying the stable complexation and coordination mechanism. The optimum pH solution was evaluated before selecting the separation and uptake operations and the pH was 5.0 to avoid the hydroxyl precipitation rather than adsorption based on the Ln(III) chemistry. The fabricated CHM was exhibited the high kinetic performances. The adsorption data were highly fitted with the Langmuir isotherms model and the maximum Yb(III) adsorption amount was found 139. 19 mg/g. The results were also affirmed that the effect of competing ions were not affected seriously in the Yb(III) adsorption. After successful adsorption, the Yb(III) ion was recovered with elution operation using 0.40 M HNO3 and the CHM was also regenerated at the same time for next adsorption process after washing with water. Moreover, the reuses of the CHM were possible in several cycles complying the cost-effective potential material in real waste sample treatment.