Zeolite-hydrogel composites for lithium and arsenic extraction from geothermal waters

The rapid increase in lithium demand, driven by the growth of electric vehicles and energy storage systems, has raised concerns about future supply. To support the lithium supply chain, it is necessary to explore new sources, one of which is geothermal water. In this study, we review the current state of adsorption methods for lithium extraction from geothermal water and present our own approach. A zeolite-hydrogel composite was prepared using natural clinoptilolite, sodium alginate, and chitosan through a direct mixing method. Adsorption tests were performed using untreated geothermal water from the Dieng Geothermal Power Plant in Central Java to reflect natural conditions. The material’s performance was evaluated by comparing ICP-MS analysis results of the water before and after adsorption. The results showed no significant reduction in lithium content. However, the use of 1.5 g of the composite, prepared from 5 g of clinoptilolite and a solution containing 0.5% sodium alginate and 0.5% chitosan- reduced arsenic concentration by approximately 52%. To enhance lithium adsorption, further optimization is required, including pH adjustment, silica removal, or modification of the composite structure. Further research is also needed to further explore the material’s potential for arsenic removal.