Ni-doped MIL-53(Fe) nanoparticles for optimized doxycycline removal by using response surface methodology from aqueous solution.

This study proposes a facile one-pot solvothermal method to prepare Ni-doped MIL-53(Fe) nanoparticles as high-performance adsorbents for doxycycline removal. The morphology and structure of the samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, fourier transform infrared spectrum and thermogravimetric analysis. These results reveal that nickel was doped into MIL-53(Fe) successfully via a facile reaction, and the obtained Ni-doped MIL-53(Fe) nanoparticles showed excellent stability. The adsorption activities were evaluated in terms of the removal efficiencies of doxycycline (DOX) in aqueous solution. According to the response surface quadratic model (RSM), the optimal adsorption conditions were concentration of DOX 100 mg/L, temperature 35 °C, ionic strength 5 g/L and pH 7. The as-synthesized Ni-doped MIL-53(Fe) nanoparticles showed better adsorption capacity of 397.22 mg/g compared with other adsorbents. The investigation of adsorption mechanism demonstrated that the adsorption process was dominated by electrostatic and π-π stacking interactions. The Ni-doped MIL-53(Fe) nanoparticles with improved adsorption activities would have a great potential in DOX removal from aqueous environment.