Synthesis of mesoporous MIL-100(Fe) from acid mine drainage sludge for norfloxacin removal: Industrial sludge high value utilization, adsorbent performance and contaminant removal mechanisms

Recovery of heavy metals from acid mine drainage sludge (AMDs) and their conversion into high value-added materials such as metal-organic frameworks (MOFs) is of great significance for sustainable development. MOFs have broad application prospects in liquid phase pollutant removal, owing to super high specific surface area and adjustable structure. In this study, MIL-100(Fe) with mesoporous structures was successfully prepared from AMDs by acid leaching-hydrothermal method. And the obtained MIL-100(Fe) was employed as an adsorbent for adsorptive norfloxacin (NOR) removal from wastewater. The adsorption results showed that the maximum adsorption capacity can reach 280.84 mg/g under the condition of 298 K, the initial pH value of solution is 10 and the dosage of catalyst is 0.1 g/L. According to the N2 sorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) characterization, the adsorption mechanism of NOR on MIL-100(Fe) is mainly attributed to electrostatic interaction, π-π stacking, pore filling and coordination. Furthermore, the adsorbent maintained 75.05% of its initial adsorption capacity after 5 cycles, indicating that MIL-100(Fe) has excellent stability. This study provides a new idea for the resource utilization of industrial sludge.