Green recovery of lithium from geothermal water based on a novel lithium iron phosphate electrochemical technique

With the increasing demands for lithium, the recovery of lithium from liquid minerals has become a research focus worldwide. The green recovery of a low concentration of lithium from geothermal water was carried out in this work based on the LiFePO₄/FePO₄ technique. The composite LiFePO₄ electrode was prepared first and then electrochemically delithiated to obtain a FePO₄ electrode. When the LiFePO₄ and FePO₄ electrodes were used to construct an electrochemical system in an H-type electrolytic cell, it had high response to low concentrations of Li⁺ at 1.0 V. The electrochemical adsorption capacity was successfully increased by 57.02% which was 17.10 mg g^‑1 in the geothermal water by using PEG-6000 as a poregen to obtain pore structures on the surface of electrode. The recovery rate of Li⁺ reached 90.65% after eight adsorption-desorption cycles. Subsequently, a novel electrochemical device was proposed for the recovery of low concentrations of Li⁺ by the LiFePO₄/FePO₄ technique. Only electrical energy was consumed and no organic solvents or other toxic reagents were used during the recovery process. All these properties make the developed method a green and promising candidate for the recovery of Li⁺ from geothermal water.