This study examined the influence of operating parameters on the electrosorptive recovery system of lithium ions from aqueous solutions using a spinel-type lithium manganese oxide adsorbent electrode and investigated the electrosorption kinetics and isotherms. The results revealed that the electrosorption data of lithium ions from the lithium containing aqueous solution were well-fitted to the Langmuir isotherm at electrical potentials lower than –0.4 V and to the Freundlich isotherm at electrical potentials higher than –0.4 V. This result may due to the formation of a thicker electrical double layer on the surface of the electrode at higher electrical potentials. The results showed that the electrosorption reached equilibrium within 200 min under an electrical potential of –1.0 V, and the pseudo-second-order kinetic model was correlated with the experimental data. Moreover, the adsorption of lithium ions was dependent on pH and temperature, and the results indicate that higher pH values and lower temperatures are more suitable for the electrosorptive adsorption of lithium ions from aqueous solutions. Thermodynamic results showed that the calculated activation energy of 22.61 kJ mol–1 during the electrosorption of lithium ions onto the adsorbent electrode was primarily controlled by a physical adsorption process. The recovery of adsorbed lithium ions from the adsorbent electrode reached the desorption equilibrium within 200 min under reverse electrical potential of 3.5 V.

Abstract
 1. Introduction
 2. Experimental
  2.1. Preparation of electrodes
  2.2. Preparation of the test cell
  2.3. Electrosorption properties
  2.4. Adsorption kinetics
  2.5. Adsorption isotherms
  2.6. Activation energy
 3. Results and Discussion
  3.1. Adsorption kinetics
  3.2. Adsorption isotherms
  3.3. Effect of temperature
  3.4. Activation energy
  3.5. Effect of pH
  3.6. Desorption characteristics
 4. Conclusions
 References

• Dong-Hee Lee(Department of Chemical Engineering and Applied Chemistry, Chungnam National University)
• Taegong Ryu(Mineral Resources Research Division, Korea Institute of Geoscience and Mineral Resources)
• Junho Shin(Department of Biological Engineering, Inha University)
• Young Ho Kim(Department of Chemical Engineering and Applied Chemistry, Chungnam National University) Corresponding Author