Lithium sorption properties of HMnO in seawater and wastewater

The lithium concentration in seawater is 0.17 mg/L, which is very low, but the overall quantity is approximately 2.5 × 1014 kg. Therefore, seawater, which contains a vast amount of lithium, could be a major alternative source that might supply the rising demand for lithium. This research was undertaken to evaluate the feasibility of a manganese oxide (HMnO) adsorbent, which was produced after leaching lithium from lithium manganese oxide, for lithium collection from seawater. The HMnO was synthesized and deformed to a plastic after wet blending of manganese oxide and lithium hydroxide, and subsequently, the influence of pH, sorption isotherms, sorption rates, sorption energies, and effects of the co-ions were measured. Thermodynamic parameters such as ΔG°, ΔH°, and ΔS° indicated that the nature of the lithium sorption was both spontaneous and endothermic. The used HMnO could be regenerated by washing it with an HCl solution. The results demonstrated that HMnO could be effectively used for the collection of lithium from seawater with good selectivity.