Morphology and adsorption of chromium ion on uranium 1,2,4,5-benzenetetracarboxylic acid metal organic framework (MOF)

In this paper, we report the synthesis of metal organic framework of uranium 1,2,4,5-benzenetetracarboxylic acid (U-H(4)btec MOF) by solvothermal method. The obtained MOF was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD), energy dispersive spectroscopy (EDS), thermogravimetric and differential thermos-gravimetric analysis (TGA/DTA). The morphology of the uranium 1,2,4,5-benzenetetracarboxylic acid MOF observed by SEM, revealed the presence of flaky porous structure. Adsorption of Cr3+ from aqueous solution onto the uranium 1,2,4,5-benzenetetracarboxylic acid MOF was systematically studied. Langmuir and Freundlich adsorption isotherms were applied to determine the adsorption capacity of the MOF to form a monolayer. Kinetic determination of the adsorption of Cr3+ suggested both chemisorption and physisorption probably due to the presence of carbonyl groups within the MOF and its porous structure.