Manganese-based lithium-ion sieve prepared by chelation with aluminum sec-butoxide for an extremely low manganese dissolution rate and extended service life

• Uniform Al doping enhanced the adsorption performance of HAEMO-6% and reduced the dissolution of manganese. • Extended service life. • Excellent selective adsorption performance for Li + in brines with a high Mg 2+ /Li + ratio. • Optimizing the lithium extraction process from brine enhances Li + recovery. The growth of the lithium battery industry has significantly heightened interest in the recovery of lithium ions from salt lakes, prompting advancements in lithium-ion sieves. However, manganese-based lithium-ion sieves experience considerable manganese dissolution during the regeneration process, which adversely affects their service life. To address this issue and enhance lithium adsorption in brines with high Mg 2+ /Li + ratios, aluminum sec -butoxide was utilized to combine with a chelated compound of ethylenediaminetetraacetic acid and manganese carbonate. Through a series of processes involving high-temperature calcination, hydrothermal reactions, and acid treatment, aluminum-doped manganese-based lithium-ion sieves (HAEMO) were produced. Notably, HAEMO with 6 % aluminum doping (HAEMO-6 %) demonstrated a specific surface area of 93.53 m 2 /g and a lithium adsorption capacity of 37.82 mg/g. After undergoing five regeneration cycles, HAEMO-6 % retained 90 % of its initial capacity, with a manganese dissolution rate of less than 0.83 %, in contrast to 2.01 % observed in the undoped variant. The superior performance of HAEMO-6 % can be attributed to the uniform distribution of aluminum throughout the adsorbent matrix, which effectively minimizes Mn 3+ content and consequently reduces manganese dissolution, thereby prolonging operational life. Additionally, it exhibits remarkable selectivity for Li + in high Mg 2+ /Li + brines, achieving an optimized capacity of 20.56 mg/g. This positions HAEMO-6 % as a promising candidate for lithium extraction from salt lakes.