Lithium adsorption from aqueous solution using aluminum hydroxide: Characterization, optimization by response surface methodology, kinetic modelling, and isotherm studies

The growing need for Lithium (Li) chemicals for industrial application demands finding affordable and environmentally friendly ways of producing them beyond conventional land mining. Adsorption is a promising technique for Li recovery as it selectively extracts Li from aqueous resources at a low cost and with minimal energy requirements. The use of adsorption for Li recovery is important for promoting a circular economy and decreasing natural Li in the environment. Thus, this study aim to assess the efficiency of aluminum hydroxide (Al(OH)₃) as an adsorbent for Li recovery from aqueous solution by adjusting the amount of adsorbent, time, Li concentration, and pH. The use of Al(OH)₃ provides selective separation of Li ions and can be used as a simple and cost-effective method for purifying Li-containing solutions. The optimal conditions for the adsorption process were determined using the Box-Behnken in response surface methodology (RSM). The findings revealed that the highest removal was anticipated with a 1150 mg/L adsorbent dose, 4.5 pH, 1150 mg/L initial concentration, and 255 minutes contact time. The outcome of the finding supports the use of Al (OH)₃ as a suitable choice for recovering Li due to its greater capacity for sorption and higher percentage of Li absorbed. The analysis of the isotherm and kinetic experiment results showed that the Temkin isotherm and the pseudo-first-order model were well-fitting, with R² values of 0.998 and 0.999, respectively. This study emphasizes the effectiveness of Al(OH)₃ in recovering Li and details the optimal adsorption process. As a result, Al(OH)₃ has been presumed to be the most suitable choice for Li recovery because it outperforms other available adsorbents with high sorption ability.