Adsorptive removal of ibuprofen to binary and amine-functionalized UiO-66 in the aquatic environment: synergistic/antagonistic evaluation.

Abstract

The removal of ibuprofen (IBP) from the aqueous solution by metal-organic frameworks such as UiO-66, UiO-66-NH2, and a binary MOF (UiO-66@5%HKUST-1) was studied. MOFs were synthesized by the solvothermal method. The synthesized MOFs were characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and N2 adsorption. BET results showed that binary MOF and UiO-66-NH2 had a smaller surface area and were mesoporous compared to UiO-66, while UiO-66 was microporous. Quantitative investigations were conducted to understand the effect of binary and functional UiO-66 in adsorbing IBP and compared to UiO-66. The results showed that UiO-66 with 213mg/g had the highest adsorption in comparison to other adsorbents. UiO-66-NH2 showed the lowest adsorption (96mg/g) due to a large decrease in the surface area. The binary MOF, despite a slight decrease in surface area (1277.6 m2/g), had lower adsorption than UiO-66 (147mg/g) due to the antagonistic effects between the adsorbent and IBP. Furthermore, the pH of the solution had a great effect on the adsorption of IBP, and the results showed that increasing the pH values above 4 reduced the adsorption of IBP.