Formulation of Manganese-Based Lithium-Ion Sieves by Surfactant-Assisted Nonsolvent-Induced Phase Separation

Abstract

Manganese-based lithium-ion sieves for lithium adsorption from liquid lithium resources have garnered significant attention. However, challenges arise from the low adsorption capacity and sluggish kinetics of some particle adsorbents derived from shaped lithium-ion sieves, particularly due to their dense and hydrophobic surface characteristics. The nonsolvent phase separation technique is employed to create spherical lithium-ion-sieve precursors (PLMO) with N,N-dimethylformamide as a solvent and polyvinyl chloride as a binder in this study. Following acid treatment, PHMO particles are obtained, and their surface properties, such as porosity and hydrophilicity, are tailored through sodium dodecyl sulfate (SDS) treatment. The results indicate that PLMO particles with a 5% SDS content exhibit high porosity, forming a stable porous outer layer and supporting finger-like structure. The hydrophilic groups facilitated by SDS on the particle surface enhance the overall hydrophilicity of PHMO. Notably, PHMO with 5% SDS (PHMO-5%) displays an adsorption capacity of 14.66 mg/g, which is attributed to its porous and hydrophilic surface. An increase in the ion sieve precursor proportion significantly boosts the adsorption performance of PHMO-5%, reaching 18.34 mg/g with an 80% addition. The adsorption process follows both the Langmuir and pseudo-second-order kinetic models, and PHMO-5% demonstrates high selectivity for lithium ions in industrial waste solutions containing silicon.