Valorization of Manganese Ore Tailings from the Borly Deposit into Functional Sorbents
Abstract
This study reports the synthesis and characterization of a novel sorbent from manganese ore beneficiation tailings (Borly deposit, Kazakhstan), activated with 20% phosphoric acid and thermally treated at 600 °C. Compared to the raw material, the sorbent showed reduced BET surface area (6.05→3.02 m2/g) but increased average pore diameter (13.2→21.8 nm), more negative zeta potential (−4.1→−18.9 mV), and lower water solubility (0.82%). Equilibrium tests revealed ≥99% Cu2+ removal and a maximum capacity of 1.329 mg/g, with a type V isotherm indicating cooperative adsorption on heterogeneous sites. Among tested models, the RALF (Redlich–Anderson–Langmuir–Freundlich) isotherm provided the best fit (R2=0.999), confirming structured and energetically diverse adsorption sites. Kinetics followed a pseudo-second-order model (R2≈1), suggesting chemisorption with mixed physisorption contributions, while intraparticle diffusion was not the sole rate-limiting step. Fixed-bed tests showed a dynamic capacity of 0.68 mg/g. The results highlight a sustainable approach to valorizing manganese tailings for efficient copper removal. This work demonstrates a sustainable approach to valorizing mining waste into functional sorbents for heavy metal removal. Despite their modest adsorption capacity, the materials show high removal efficiency and low cost, making them promising for polishing treatment and other cost-sensitive applications.