Green chitosan–starch–polyvinyl alcohol bio-composite hydrogel for zirconium capture from zircon raffinate

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2026年6月24日

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G. A. Dakroury,
Sh. M. Abdo,
E. A. A. El Shazly

摘要

A novel polymer-based sorbent comprising three blended components was synthesized via aqueous mixing and ultrasonication for the efficient removal of Zr(IV) from highly acidic solutions. Characterization by FT-IR, SEM, and surface area analysis confirmed active functional groups and a mesoporous structure (16.704 m² g⁻¹, 3 nm pores). Batch studies revealed that maximum uptake (102 mg g⁻¹) occurred at pH 1.25 after 120 min at 20 °C, increasing to 188 mg g⁻¹ with higher initial concentrations (50–750 mg L⁻¹). Uptake decreased at elevated temperatures (293–323 K), indicating exothermic adsorption. Kinetic analysis was consistent with adsorption involving surface interactions and was best described by the pseudo-second-order and Elovich models, while equilibrium data were better fitted by the Freundlich model, suggesting a heterogeneous adsorption surface. Thermodynamic parameters (ΔG = –18.84 to –19.60 kJ mol⁻¹; ΔH = − 11.35 kJ mol⁻¹; ΔS = 25.57 J mol⁻¹ K⁻¹) confirmed a spontaneous and exothermic process. The sorbent remained stable in acidic media up to 2 M H₂SO₄ and was effectively regenerated, with H₂SO₄ achieving the highest desorption efficiency. These findings suggest that the prepared material shows potential as an effective sorbent for Zr(IV) recovery from acidic process streams.