Application of concentration-dependent HSDM to the lithium adsorption from brine in fixed bed columns

Adsorption of lithium ions from simulated brine using layered lithium-aluminum hydroxides was investigated at 303 K in fixed-bed columns. The lithium adsorption isotherms in simulated brine were conducted using batch system, and the Langmuir isotherm model was found to fit the equilibrium data well. The effects of initial lithium concentration (C-0, 200-400 mg/L), bed height (H, 30-200 cm), and feed flow rate (Q, 6-18 mL/min) on lithium breakthrough curves in packed bed columns were investigated systematically. In order to simulate the practical operation process, the breakthrough time was defined when the lithium recovery rate dropped down to 0.6. The column adsorption performance was improved with the increasing of bed height and the decreasing of the initial lithium concentration, feed flow rate. Furthermore, the Homogeneous Surface Diffusion Model (HSDM) with concentration-dependent surface diffusion coefficient was developed to simulate and predict the lithium adsorption curves. The numerical model results showed good agreement with the experimental data in simulated brine and factual brine circumstance, which proved that the model could successfully simulate the column adsorption process of lithium recovery. These results provided important information to design, optimize and scale-up the column adsorption process for lithium recovery from brine.