Utilization of Electrodeionization for Lithium Removal

Abstract

In this work, usage of a hybrid polymeric ion exchange resin and a polymeric ion exchange membrane in the same unit to remove Li + from aqueous solutions was reported. The effects of the applied potential difference to the electrodes, the flow rate of the Li-containing solution, the presence of coexisting ions (Na + , K + , Ca 2+ , Ba 2+ , and Mg 2+ ), and the influence of the electrolyte concentration in the anode and cathode chambers on Li + removal were investigated. At 20 V, 99% of Li + was removed from the Li-containing solution. In addition, a decrease in the flow rate of the Licontaining solution from 2 to 1 L/h resulted in a decrease in the removal rate from 99 to 94%. Similar results were obtained when the concentration of Na 2 SO 4 was decreased from 0.01 to 0.005 M. The selectivity test showed that the simultaneous presence of monovalent ions such as Na + and K + did not change the removal rate of Li + . However, the presence of divalent ions, Ca 2+ , Mg 2+ , and Ba 2+ , reduced the removal rate of Li + . Under optimal conditions, the mass transport coefficient of Li + was found as 5.39 × 10 −4 m/s, and the specific energy consumption was found as 106.2 W h/g LiCl. Electrodeionization provided stable performance in terms of the removal rate and transport of Li + from the central compartment to the cathode compartment.

Feasibility of electrodeionization for phosphate removal

“…Thus, an increase in flow rate of the solution enhances the k and j values of phosphate. Furthermore, another factor that may be affecting the results is the decrease in the thickness of the liquid coating on the surface of the resin particles, which subsequently enhances the transport of ions (Demir et al, 2023;Helfferich, 1995). Table 3 also shows that the pH of the solution affected the values of j, k, and SPC.…”

“…Past studies have investigated the use of EDI in both continuous and batch modes. In the first case, decreasing the flow rate increases the ion removal rate because of the longer residence time, whereas in the second case, passing the same solution through the EDI cell multiple times increases the ion removal rate because of the lower film thickness and longer circulation times (Demir et al, 2023). Consequently, it is deduced that the feed flow rate can affect ion removal via EDI in several ways.…”