Removal of Acid Orange 7 from Aqueous Solution by Metal-Organic Frameworks

We investigated the removal of a harmful anionic dye, acid orange 7 (AO7), from aqueous solution using metal-organic frameworks (MOFs). We prepared four different MOFs (ZIF-8, ZIF-67, UiO-66, UiO-66-NH2) by solvothermal reactions and then tested their adsorption of AO7. Infrared spectra and adsorption capacity data confirmed the removal of AO7 from aqueous solution. The factors we investigated affecting adsorption capacity include variation of the organic linkers and metal clusters of the MOFs. Our results suggest that the hydrogen bonding, - interactions, and zeta potentials facilitate the removal of AO7 from water. Of the four MOFs examined, ZIF-67 exhibited the highest adsorption capacity of AO7 and can be regenerated easily.