Equilibrium and kinetic studies of an electro-assisted lithium recovery system using lithium manganese oxide adsorbent material
관리자2018-11-06조회 4104
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.
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