Lithium extraction from unconventional aqueous resources – A review on recent technological development for seawater and geothermal brines

The increasing adoption of lithium in clean energy technologies has promoted significant development of novel and environmentally sustainable techniques for lithium extraction from secondary sources. In this review, we evaluate seawater and geothermal brines as potential secondary lithium resources for supplementing the rising demand. The review examines relevant literature to understand key aspects pertaining to lithium extraction from these systems in which the fundamental chemistry, the efficacy of different potential extraction techniques, and the associated impacts of each technique are critically reviewed. The extensive research in conventional closed basin brines is utilized as a baseline to demonstrate the current research progress, providing guidelines for future research direction in lithium extraction from seawater and geothermal brines. Based on the literature, it is suggested that sorption and ion-exchange will have high potential for prospective lithium extraction from aqueous resources like salars, seawater, and geothermal brines, and that the integration of activated carbon materials or microorganisms with these techniques will enhance the selectivity of lithium extraction from aqueous resources.