Adsorption Behavior of Metal-organic Framework NH2-MIL-53(Al) for Diclofenac Sodium in Aqueous Solution

The metal-organic framework(MOF) material of NH2-MIL-53(Al) was solvothermally synthesized, and characterized by powder X-ray diffraction(PXRD), scanning electron microscopy(SEM) and Fourier transform infrared spectroscopy(FTIR). The adsorption behavior of the as-prepared NH2-MIL-53(Al) for diclofenac sodium(DCF) was studied in aqueous solution. The experimental results showed that NH2-MIL-53(Al) had a high adsorption capacity on the target material and reach adsorption equilibrium in 40 min when the concentration of DCF was 5 mg/L. Furthermore, the adsorption kinetics of NH2-MIL-53(Al) for DCF conformed to the pseudo second-order kinetics model. Langmuir model and Freundlich model were used to fit the adsorption isotherms, and the Langmuir model showed a better fit. The experiment of cyclic adsorption showed that NH2-MIL-53(Al) had a good recycle performance. Moreover, the possible adsorption mechanism was demonstrated by the combination of zeta potential tests and adsorption effect experiments under different pH values.