Process design for lithium recovery using bipolar membrane electrodialysis system

• Application EDI process for recovery lithium ion using bipolar membrane.
• Comparing with chemical and electrical desorption efficiency.
• Main factors of BEDI process for optimization were evaluated.
• Useful method for recovery lithium ion was suggested.

This study aims to evaluate the effect of LMO (lithium manganese oxide) and enhanced BEDI (bipolar membrane electro-dialysis deionization) on the lithium ion desorption process for the recovery of lithium ions. The factors that influence lithium ion recovery are evaluated in reference to the pH, voltage, flow rates, and number of bipolar membrane sheets to present the optimal conditions. The research findings show that in the desorption of LMO lithium ions, the lower the pH, the higher the desorption rates. When the voltage was 6.5 V per sheet, the desorption rates were approximately 70%, and when flow rates were 0.44 mL/cm2 min, the desorption was approximately 30 min faster than that at other flow rates. When the number of bipolar membrane sheets was 4, it was possible to control 4 the pH to under 4, a level at which lithium ions adsorbed onto LMO might affect the desorption phenomenon. For a combination of the conditions above, the desorption efficiency of lithium ions was approximately 70%, and the recovery time was reduced by approximately 180 min compared to when a chemical process was used for lithium ion desorption.