| Autor: |
Hu Y; Department of Chemistry , Université Laval , Québec G1V 0A6 , QC , Canada.; Centre en Catalyse et Chimie Verte (C3V) , Université Laval , Québec G1V 0A6 , QC , Canada., Misal Castro LC; Department of Chemistry , Université Laval , Québec G1V 0A6 , QC , Canada.; Centre en Catalyse et Chimie Verte (C3V) , Université Laval , Québec G1V 0A6 , QC , Canada., Drouin E; Department of Chemistry , Université Laval , Québec G1V 0A6 , QC , Canada.; Centre en Catalyse et Chimie Verte (C3V) , Université Laval , Québec G1V 0A6 , QC , Canada., Florek J, Kählig H, Larivière D; Department of Chemistry , Université Laval , Québec G1V 0A6 , QC , Canada.; Centre en Catalyse et Chimie Verte (C3V) , Université Laval , Québec G1V 0A6 , QC , Canada., Kleitz F, Fontaine FG; Department of Chemistry , Université Laval , Québec G1V 0A6 , QC , Canada.; Centre en Catalyse et Chimie Verte (C3V) , Université Laval , Québec G1V 0A6 , QC , Canada.; Canada Research Chair in Green Catalysis and Metal-Free Processes , Québec G1V 0A6 , Canada. |
| Abstrakt: |
The separation and preconcentration of rare earth elements (REEs) from mineral concentrates in an economically and environmentally sustainable manner are difficult tasks due to their similar physicochemical properties. Herein, a series of tetradentate phenylenedioxy diamide (PDDA) ligands were synthesized and grafted on large-pore three-dimensional KIT-6 mesoporous silica. In solid-phase extraction, the hybrid sorbents enable a size-selective separation of REEs on the basis of the bite angles of the ligands. In particular, smaller REE 3+ ions are preferentially extracted by KIT-6-1,2-PDDA, whereas light REEs with larger ionic radius are favored by KIT-6-1,3-PDDA. The exposure of bauxite residue digestion solution containing REEs as well as a number of types of competitive ions (including Th and U) to the sorbents results in selective recovery of target REEs. The possibility of regenerating the mesoporous sorbents through a simple loading-stripping-regeneration process is demonstrated over up to five cycles with no significant loss in REE extraction capacity, suggesting adequate chemical and structural stability of the new sorbent materials. |
