Lithium recovery from water by granulated PVC/PAN- titanium type lithium ion-sieve

Lithium consumption and the need for production have been in rising trend due to increase in electric vehicles and energy storage systems. Lithium was nominated as a critical element, which means that it has no substitute. Also, the majority of the lithium was dissolved in brines, untouched. Therefore, this study investigated the performance of titanium-based lithium ion-sieve which was synthesized by solid-phase change method and immobilized by granulation with PVC and PAN polymers for lithium recovery from water bodies. The granulated adsorbent, PVC/PAN-HTO, was characterized by FT-IR, BET, XRD, and SEM analyses which revealed that material successfully synthesized. Moreover, batch adsorption experiments were carried out to investigate performance. Lithium recovery occurs in alkaline medium as the point of zero charge being 6.03; below this pH level, lithium stripping takes place. Optimum lithium recovery rate of 98.7% was achieved at pH 12 using a 4 g/L adsorbent dosage in model lithium solution, while in geothermal water, with the same adsorbent dosage, a recovery rate of 91.6% was attained. Kinetic study revealed the rate constants of the reaction for pseudo first and second order, while the latter fits better. Langmuir isotherm at 25 °C, which resulted maximum adsorption capacity of 5.59 mg/g, showed better fit for explanation of the adsorption behavior. Thermodynamic calculations showed that the adsorption was endothermic and spontaneous. Cycling tests showed that there was no significant decrease in lithium recovery rate after three adsorption-desorption cycles. Results indicate that the granulated adsorbent, PVC/PAN-HTO, was lithium selective, promising, and reusable.