Enhancing adsorption capacity and structural stability of Li(1.6)Mn(1.6)O(4) adsorbents by anion/cation co-doping

Modifying the structure of Li(1.6)Mn(1.6)O(4) (LMO) to enhance its structural stability and adsorption capacity is an effective method to generate materials to recover Li(+) ions from mixed solution. Herein, the co-doping of trace non-metal ion (S) and metal ion (Al) into Li(1.6)Mn(1.6)O(4) (LMO-SAl) is established and shows excellent Li(+) adsorption capacity and Mn anti-dissolution properties. The adsorption capacity (when [Li(+)] is 6 mmol L(−1)) is increased from 26.1 mg g(−1) to 33.7 mg g(−1). This is attributed to improved charge density via substitution of S at O sites, which facilitates the adsorption/desorption process. The Mn dissolution is also reduced from 5.4% to 3.0% for LMO-SAl, which may result from the stronger Al–O bonds compared to Li–O bonds that enhance the structural stability of the LMO. The ion-sieving ability of the co-doped material goes by the order of K(d) (Li(+) > Ca(2+) > Mg(2+) > Na(+) > K(+)), indicating that Li(+) can be efficiently separated from Lagoco Salt Lake brine. These results predict that lithium ions are effectively adsorbed from brine by the co-doped LMO material, which manifests the feasibility of lithium recovery and provides basic data for further industrial applications of adsorption.