Reusable and efficient clay material for the fixed-bed neodymium recovery

Abstract

Neodymium is an essential resource for the future development of clean energy. Its future supply is a global concern motivating the application of different adsorbent materials to recover neodymium from secondary sources. However, there is a lack of studies of adsorption with scale-up potential. This work aims to recuperate neodymium from aqueous solution through dynamic adsorption in a fixed-bed of expanded vermiculite, an abundant clay mineral with excellent adsorbent properties. For that, the flow rate and concentration optimization, mathematical modeling; cycles of adsorption and desorption; and the extensive characterization of the regenerated adsorbent matrix were carried out. The main findings of the study are the column high adsorption capacity 0.40 mmol/g; the effective modeling of the column by Thomas and DualSD model, being useful for scale-up purposes; the constant bed efficiency along with the cycles and the well succeed neodymium recovery (96% in the third cycle) and concentration (28.4 times). Besides that, the structural composition was maintained, attesting to the physical and chemical stability of the material. Thus, the neodymium continuous recovery from aqueous solution through successive cycles of adsorption and desorption on an expanded vermiculite fixed-bed has high potential for scale-up and rare earth rich wastewater treatment studies.