Development of H₂TiO₃-incorporated PVA/SA/PSS hydrogel beads for lithium recovery

Lithium recovery from industrial wastewater has gained increasing attention owing to the rapidly growing demand for lithium-ion batteries. Among various lithium recovery technologies, H₂TiO₃ (HTO) lithium ion sieves have been widely studied because of their high selectivity toward Li⁺ ions. However, powder-type HTO adsorbents suffer from several limitations, including particle loss, difficult solid–liquid separation, and poor reusability. To address these issues, PVA/SA/PSS-based hydrogel beads incorporating HTO were prepared for lithium adsorption. Poly(vinyl alcohol) (PVA) was used to form the basic hydrogel structure and improve mechanical stability, while sodium alginate (SA) enabled stable bead formation through ionic crosslinking with Ca²⁺ ions. In addition, poly(styrene sulfonate) (PSS) was introduced to increase hydrogel hydrophilicity and promote ion transport within the polymer matrix. Notably, even in the presence of a high concentration of competing Na⁺ ions, the HTO-loaded hydrogel beads exhibited preferential adsorption of Li⁺ ions, demonstrating their lithium selectivity under sodium-rich conditions. The resulting hydrogel beads provide a promising strategy for improving the handling, reusability, and practical application of lithium-selective adsorbents in wastewater-based lithium recovery.