ZIF-8-Functionalized Manganese-Based Lithium Ion Sieve: Synthesis and Lithium Selective Extraction

The critical role of lithium in powering the new energy economy necessitates prioritizing efficient extraction methods. This study investigates a novel zeolitic imidazolate framework (ZIF-8)-coated manganese-based lithium ion sieve (LIS) for enhanced lithium recovery. The precursor of LIS, Li1.6Mn1.6O4, was synthesized via the hydrothermal method, followed by acid pickling to obtain the spinel lithium ion sieve H1.6Mn1.6O4. The material was then immersed in a 2-methylimidazole/Zn(NO3)2 solution, undergoing ultrasonic-assisted hydrothermal growth to form ZIF@H1.6Mn1.6O4 composites. Under optimized conditions (30 °C, pH=11, 24 h), the composite demonstrated superior lithium extraction performance compared to single-phase adsorbents, reaching 26.44 mg/g at the solution with 250 mg/L Li+. The adsorption capacity of the composite increased with Li+ concentration and reaction time. The adsorption kinetics followed a pseudo-second-order kinetic model and is dominated by chemisorption.