The adsorption properties of defect controlled metal-organic frameworks of UiO-66

Abstract

• The regulated U-B and U-B-HCl can effectively remove dyes from aqueous solution. • The adsorption capacities of U-B-HCl was higher than those of reported adsorbents. • The separation coefficient of defect controlled U-B-HC on MO is as high as 9.92. The removal of two organic dyes, methyl orange (MO) and methylene blue (MB), was inspected by a new type Zr-based MOFs of UiO-66 with defects regulated via benzoic acid and hydrochloric acid. Abundant groups of Zr-OH and Zr·H 2 O were produced because of the missing-linker during defect regulation and the inherent bridging groups in the Zr-O cluster, which acted as adsorption active sites for MO and MB. Several important parameters of adsorption time, dye concentration, adsorption selectivity and adsorption cycle performance were investigated. The models of Freundlich and Langmuir isotherm were used to confirm the experimental data, where the Langmuir model fits much better for the adsorption isotherm. Compared with U-0, the adsorption capacity of U-B regulated by benzoic acid for MO and MB increased, and the adsorption capacity of U-B-HCl regulated by benzoic acid and hydrochloric acid for MO was further increased. The adsorption capacities of U-B-HCl approached as high as 1.615 mmol (528.6 mg) g −1 for MO, which was much higher than those of reported adsorbents. Moreover, The defect controlled MOF of U-B-HCl shows excellent separation performance for MO and MB, the separation coefficient of MO is as high as 9.92. The results indicated that U-B-HCl prepared by defect control has a broad application prospect as an efficient adsorbent for removing organic dyes.