Separation of Lithium and Cobalt Ions and Regeneration of Nitric Acid by Electrodialysis Using Bipolar Membranes for Water Splitting and Monovalent Cation Selective Bipolar Membranes

The demand for lithium-ion batteries has been rapidly increasing in the modern electronics and electric vehicle industries. Tremendous lithium-ion battery consumption leads to an increase in battery scrap, which has to be recycled to relieve the shortage of rare resources. We examined a new process for separation of lithium and cobalt ions, and the regeneration of nitric acid from their mixture solution by use of electrodialysis with water splitting and monovalent cation selective bipolar membranes. In the experiment with an electrodialysis cell divided between an anode and cathode with a water splitting, an anion exchange, a monovalent cation selective, and a water-splitting bipolar membrane, lithium ion selectively permeates to strip compartment through monovalent cation selective bipolar membrane. The nitrate ion also permeates through the anion-exchange membrane and regenerated to nitric acid solution by water splitting bipolar membrane. These results revealed that electrodialysis using water splitting and monovalent cation selective bipolar membrane is applicable to the selective separation of lithium and cobalt ions, and regeneration of nitric acid solution.