Manganese-based spinel adsorbents for lithium recovery from aqueous solutions by electrochemical technique

Abstract

The manganese-based spinel adsorbent (HMO) refers to lithium-ion adsorbents derived from the spinel lithium manganese oxide (LMO). Two types of lithium ions extraction composite films composed of HMO (HMn2O4 and H1.6Mn1.6O4) are successfully prepared by the blade coating method. Based on the excellent Li+ selectivity of HMO and the outstanding conductivity of conductive carbon black (C), HMO/C films are carried out to extract lithium by electrochemically switched ion exchange (ESIX) technique. HMO has a certain adsorption capacity for Li+ when the Li+ concentration is close to the actual brine, and the adsorption capacity of HMn2O4 and H1.6Mn1.6O4 is 24.56 mg/g and 34.40 mg/g, respectively. HMO showed good selectivity for Li+ in multiple metal ions solution. The capacity of HMn2O4 and H1.6Mn1.6O4 keep 80% and 86% of the initial values after 5 cycles, respectively. The inherent different lithium occupied leads to the difference of electrical-adsorption abilities between HMn2O4 and H1.6Mn1.6O4. H1.6Mn1.6O4 has a broad application prospect in lithium extraction from salt lake brine due to its lower application voltage, large adsorption capacity and superior stability.