Modification of UiO-66 for removal of uranyl ion from aqueous solution by immobilization of tributyl phosphate

Two modified metal–organic frameworks (MOFs), were synthesized by immobilization of tributyl phosphate (TBP) on the UiO-66 and vacated UiO-66 (UiO-66-vac), and investigated for the removal of uranyl ion from aqueous solution. Characterization of MOFs was carried out by various techniques such as X-ray diffraction (XRD), Fourier Transform Infra-Red Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), and BET surface area. FTIR confirmed efficient immobilizing of the TBP on the MOFs. Sorption results show that modification of MOFs enhances uranyl sorption capacity. Kinetics of sorption was investigated by pseudo-first-order and pseudo-second-order models. It is shown that at pH 5, sorption equilibrium for all MOFs, reaches a little more than 8 h. Equilibrium studies were done by Langmuir and Freundlich models and the sorption capacity of UiO-66, UiO-66-vac, UiO-66-TBP and UiO-66-vac-TBP obtained 177.1, 193.8, 201.9 and 203.5 mg g −1 , respectively. Moreover, TBP immobilized MOFs, show more selectivity than UiO-66 and UiO-66-vac towards uranyl in wastewater containing cationic and anionic interferences. The effect of the contact time and pH for maximum removal of uranyl was studied. Graphic abstract Two modified metal–organic frameworks (MOFs), were synthesized by immobilization of tributyl phosphate (TBP) on the UiO-66 and vacated UiO-66 (UiO-66-vac), and investigated for the removal of uranyl ion from aqueous solution.