Application of Amino-Functionalized Metal-Organic Framework UiO-66-NH₂ in the Remediation of Multi-Metal-Contaminated...

Traditional adsorbents, such as clay minerals, mainly target metal cations, which limits their effectiveness in mining soils where multiple metals and oxyanionic species coexist. To address this limitation, we evaluated amino-functionalized UiO-66-NH₂ as a stabilizing amendment capable of immobilizing both anionic and cationic metal species. This study evaluated its stabilization performance for vanadium (V), chromium (Cr), nickel (Ni), and zinc (Zn) in typical mining soils. Soil samples were amended with 1%, 2%, and 3% dosages and incubated for 50 days to systematically analyze leaching behavior, speciation transformation, and microbial community responses. At 50 days, the 1% UiO-66-NH₂ treatment reduced the leaching concentrations of V, Cr, Ni, and Zn by 90.42%, 59.72%, 90.12%, and 90.71%, respectively. Although Cr showed its highest reduction efficiency under the 3% treatment, the 1% dosage provided a practical compromise for multi-metal stabilization rather than a universal optimum. The stabilization process was primarily driven by surface complexation and ion exchange, which facilitated the transformation of metals into stable oxidizable forms. The amendment increased soil organic matter (SOM) and cation exchange capacity (CEC), triggering competitive adsorption and increasing the mobility of Zn and Ni. Microbial profiling revealed a successional shift toward resilient taxa, specifically the proliferation of Actinomycetota and Arthrobacter. These findings established that a 1% UiO-66-NH₂ amendment provides a robust and ecologically compatible strategy for the sustainable remediation of complex mining-impacted environments.