Innovative approaches for recycling old batteries solution through the precipitation of ZIFs
Résumé
Up to this day, the recycling process in primary batteries involves (hydro) metallurgic processes to produce drip trays, a rather high cost procedure for a low cost material. Herein, we report the selective precipitation of zinc into Zeolitic Imidazolate Frameworks (ZIFs) from a polymetallic aqueous solution, derived from a black mass sample of alkaline (primary) batteries containing metals like Zn, Mn, Ni, Cu, Al, Fe and Co. The synthesis conditions were adapted in order to switch from a methanolic to an aqueous solution, as well as using sulfate precursors instead of nitrates. With the help of benzimidazole or 2-methylimidazole, ZIF-7-III and ZIF-8 precipitated accordingly, leading to a recovery of more than 99 % of zinc in a one-step and one-pot reaction.
Both materials (ZIF-7-III and ZIF-8) were calcined in hydrogenated argon atmosphere, forming metal zinc that was collected as a deposit around the furnace tube and could be involved in the making of new alkaline or Zn-air batteries. The high BET area of ZIF-8 (1300-2000 m2/g) permits the further valorization in adsorption and the trapping of propylene and propane.
Finally, more than 50 % of the ligand can be easily recycled and used at new in the process of precipitation. Both loops involve a less energy consuming process, isolating a product of a high value. The closed loop provides a pathway in order to reassemble alkaline batteries, whereas the open loop permits the use in high-importance procedures.
Domaines
ChimieOrigine | Fichiers produits par l'(les) auteur(s) |
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