Lithium recovery from aqueous solution using zirconium-enhanced ion sieve

The growing demand for lithium-ion batteries necessitates the development of sustainable methods for extracting lithium. Geothermal brines offer a promising source of lithium, but their complex ionic composition poses a challenge to selective recovery. Hydrogen manganese oxide (HMO, H 4 Mn 5 O 12 ) exhibits exceptional lithium selectivity but suffers from structural instability and manganese dissolution during cycling. To address this, zirconium (Zr) was incorporated into the spinel framework, synthesizing Li 4 Mn 4 . 5 Zr 0 . 5 O 12 (LMZO) via single-step calcination (450 °C, 6 h). Acid treatment converted LMZO to H 4 Mn 4 . 5 Zr 0 . 5 O 12 (HMZO), characterized using EDS, SEM, BET, and FTIR. HMZO demonstrated a 35 mg/g lithium adsorption capacity with only 0.78% manganese dissolution. After five adsorption–desorption cycles, it retained a capacity of 25.89 mg/g, highlighting enhanced stability. Kinetic analysis revealed pseudo-second-order adsorption, while equilibrium data fit the Freundlich isotherm, indicating heterogeneous ion exchange. Thermodynamically, the process was endothermic and entropy-driven, with improved performance at higher temperatures. This Zr-stabilized sieve combines high selectivity, minimal manganese loss, and excellent recyclability, offering a sustainable pathway for lithium extraction from geothermal brines and advancing green energy storage.