Efficient adsorption of tetracycline in water by Mn and Ce co-doped MIL-100 composite oxide

In this study, a manganese cerium co-doped iron-based metal-organic frameworks composite oxide nanomaterial (MnCe/MIL-100) was prepared by solvothermal method and used to adsorb tetracycline (TC) from water. Scanning electron microscope, energy dispersive spectroscopy (EDS), X-ray diffraction were used to study the micro morphology, main element composition and crystal struc-ture of the adsorbent. The experimental results were fitted by adsorption kinetics, adsorption isotherms and other models. In addition, the influence of the dosage of adsorbent and the pH of the solution on the adsorption performance and the reusability of the composite were also studied. It was found that the adsorption rate of MnCe/MIL-100 to TC can be as high as 100%. The adsorp-tion kinetics of TC on MnCe/MIL-100 can be well described by pseudo-second-order model. At room temperature, the adsorption capacity is up to 210.971 mg/g, which is consistent with Langmuir isotherm. Through thermodynamic analysis, it is found that this process has the characteristic of absorbing heat, and this absorption is spontaneous. Meanwhile, MnCe/MIL-100 still has good TC adsorption capacity after five cycles, showing good reusability, which is of great significance to cost saving and environmental pollution reduction. Finally, the analysis by Fourier-transform infrared spectroscopy and zeta potential explain the mechanism of TC adsorption.