Multifunctional Metal-Organic Framework/Alkali-Etched Silicon Carbide Composite for Efficient Strontium Adsorption...

With the acceleration of global industrialization, chemical residues of radionuclides and organic pollutants in water bodies have become an increasingly severe issue. This study developed a ternary heterogeneous structural material, ZIF-8@ZIF-67/AE-SiC, which served as a dual-functional material combining both nuclide adsorption and organic pollutant degradation capabilities. Alkali-etched silicon carbide (AE-SiC) was introduced as a functional carrier, combining the confinement effect of ZIF-8 with the redox activity of ZIF-67 to enhance surface activity and mass-transfer efficiency. On the one hand, ZIF-8@ZIF-67/AE-SiC exhibited a maximum theoretical adsorption capacity of 52.07 mg/g for Sr. The adsorption process was well described by the pseudo-first-order kinetic model and the Freundlich isotherm, and the material exhibited good selectivity under competitive ions. On the other hand, ZIF-8@ZIF-67/AE-SiC removed over 95% of ciprofloxacin (CIP) within 20 min, and showed good efficiency in removing low concentrations (100 μg/L) of CIP. It maintained high-efficiency degradation across a wide pH range (5-11) and temperature range (15-45 °C), and exhibited broad-spectrum degradation capabilities of over 85% for other pollutants. The synergistic effects of radical and nonradical pathways dominated by SO₄^•- and ¹O₂ enable rapid decomposition of pollutants. The structural stability was enhanced due to the stabilizing effect of the Si-O-M bonds and the supporting role of the shell-core structure, resulting in a 60-80% reduction in Zn/Co leaching concentrations compared to pure ZIFs. This work provides a new approach for developing efficient and multifunctional water treatment materials.