Preparation and characterization of lithium λ-MnO2 ion-sieves

Lithium lambda-MnO2 ion-sieves were prepared from spinel LiMn2O4 via treatment with nitric acid. The LiMn2O4 was synthesized by a solid state reaction between LiOH center dot H2O and MnO2. The effects of the calcination time and temperature on the preparation of the LiMn2O4 precursor and the lithium ion-sieve were investigated. In addition, the Li+ extraction ratio, the Mn2+ dissolving ratio and the adsorption properties of the lithium ion-sieve were all measured. The lithium ion-sieve had a high exchange capacity and was selective for Li+. Specifically, at pH = 13, the ion exchange capacity of Li+ was 30.9 mg/g in 10 mmol/L LiCl solution and the lithium extraction ratio and manganese dissolving ratio were 95% and 25%, respectively.