Highly efficient (Au)(III) recovery from acid wastewater by thiosemicarbazide modified Zr-MOF

The design and development of new precious metal recovery adsorbents have significant socio-economic benefits; this study successfully synthesized a high-performance gold ion adsorbent, UiO-66-TMB, by modifying UiO-66-NH₂ with thiosemicarbazide, a common industrial chemical rich in amino and thiol groups. The obtained material exhibits excellent stability and adsorption performance, with the maximum adsorption capacity of 729.15 mg·g⁻¹ at pH = 2. The adsorbent has good recyclability and can maintain superior selectivity in environments containing multiple impurity ions. In addition, even under strong acidic conditions with low initial gold ion concentration, a saturated adsorption capacity of 705.6 mg·g⁻¹ can be maintained. Mechanism studies have shown that there is a synergistic effect between electrostatic attraction, coordination binding, and redox reactions between Au and functional groups containing N and S elements on the surface of materials. The functionalization strategy proposed in this work opens new research directions for developing efficient and stable precious metal adsorption materials, offering a potential solution for sustainable resource recovery from industrial wastewater and electronic waste.