Rationally designed dipicolinate-functionalized silica for highly efficient recovery of rare-earth elements from e-waste

• Published in: Journal of hazardous materials 2021-04, Vol.408, p.124976-124976, Article 124976
• Main Authors: Artiushenko, Olena, Zaitsev, Vladimir, Rojano, Wendy S., Freitas, Gabriel A., Nazarkovsky, Michael, Saint’Pierre, Tatiana D., Kai, Jiang
• Format: Article
• Language: English
• Subjects: Dipicolinic acid; Dispersive SPE; Fluorescent lamp waste; Rare-earths elements; Surface-assembling synthesis
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2020.124976

Composition of the immobilized layer plays a crucial role in metal adsorption properties of complexing organo-mineral materials. Ignoring the specific features of chemical reactions on solid surface can lead to a significant deterioration in the target properties of the resulted materials. In this research we demonstrated that rationally designed surface-assembling synthesis of organo-silica with covalently immobilized fragments of dipicolinic acid (DPA) resulted in the adsorbent that is capable quantitively recover almost all Rare Earth elements (REEs) from multielement solution with pH > 1.7. In ten consecutive adsorption/desorption cycles no noticeable loss of its efficiency was found, with a mean value of REEs recovery larger than 97%. The adsorbent has been used to recover REEs from model solutions (22 metal ions in 0.5 mol L−1 NaCl) and real leaching solution of waste of fluorescent lamps. It was demonstrated that even 3200-fold excess of Fe and Cu ions only slightly reduces REEs recovery. The adsorbent is capable to recover above 80% of all (except La) REEs from acidic leaching solution from fluorescent lamps with enrichment factors above 600. After adsorption of Eu3+ and Tb3+, the resulting materials exhibited strong red and green luminescence, respectively, indicating chelating mechanism of REEs adsorption on SiO2-DPA. [Display omitted] •Reusable adsorbent with immobilized dipicolinic acid quantitatively recovers REEs.•Recovery of REEs in minutes from multielement solution with pH > 1.7 and Kd > 7∙103 mL g−1.•0.5 M NaCl spiked with 22 metals declines recovery of heavy REEs on 15–20%.•Above 80% of REEs recover from acidic leaching solution of fluorescent lamps.•Enrichment factors of REEs are above 600.