Study of scandium sorption from a solution of leached waste from titanium production with hydrochloric acid

This study examines the sorption of scandium from hydrochloric acid (chloride) solutions using cation exchange resins: Purolite C-150H⁺ and Purosorb SAC140H⁺. The resins were compared based on their sorption performance, including extraction efficiency, static exchange capacity, and selectivity in the presence of accompanying elements (Al and Ti). Optimal sorption conditions—pH, solid-to-liquid phase ratio, and temperature—were determined experimentally.The results show that scandium sorption on Purolite C-150H⁺ follows the Langmuir isotherm (R² = 0.9269), indicating monolayer adsorption on a homogeneous surface. In contrast, sorption on Purosorb SAC140H⁺ is better described by heterogeneous adsorption models: Freundlich (R² = 0.433) and Dubinin–Radushkevich (R² = 0.647) isotherms.