Preparation of Ion-Sieve Type (H)[M0.5Mn1.5]O4 (M=Mg, Zn) and Their Lithium Adsorption Properties in Seawater

摘要

Ion-sieve type manganese oxide spinels for the selective adsorption of Iithium(Li) from seawater were prepared and their properties were examined. LiM0.5Mn1.5O4 (M=Mg, Zn) precursors, in which part of manganese(Mn) was substituted with magnesiuni(Mg) or zinc(Zn), were synthesized through the solid-state reaction. The adsorbents, HMo.sMni 5O4 (M=Mg, Zn) were derived from LiMosMni 5O.1 (M=Mg, Zn) by acid treatment. The optimum acid treatment was obtained at hydrochloric acid concentration of 0.5M and 0.3M for LiMgo.5Mn1.5O4 and LiZno.5Mn1.5O4 precursors, respectively. Both cases required thrice-conducted acid treatments for the best results. The adsorption of Li by HMg0.5Mn1.5O4 and HZn0.5Mn1.5O4 adsorbents followed the Freundlich equation and the maximum adsorption of Li in artificial seawater was 30.3 mg/g and 33,1 mg/g, respectively. The adsorption efficiency of Li by HMgo.5Mn1.5O4 and HZno.5Mn1.5O4 adsorbents in artificial seawater, in which Li concentration was adjusted to 0.2 mg/L, was as high as 88% and 89%.