Efficient adsorption of cesium using a novel composite inorganic ion-exchanger based on metal organic framework (Ni[(BDC)(TED)]) modified matal hexacyanoferrate

The surfaces of the microporous metal-organic frameworks (Ni[(BDC)(TED)]) were modified by [KCu(Fe(CN)6)] and then it was employed as a nanocomposite ion exchanger to remove cesium ions from aqueous solutions. Various techniques such as infrared (IR) spectroscopy, X-ray diffraction (XRD), nitrogen adsorption/desorption (BET), field emission scanning electron microscopy (FESEM), Transmission Electron Microscopy (TEM), energy-dispersive X-ray analysis (EDAX), and thermogravimetry analysis were used to study the structure, morphology, composition and thermal stability of the synthesized compounds. The effects of parameters influencing adsorption, such as initial concentration of the solution, temperature, contact time, adsorbent dosage, and pH, were determined. The equilibrium data were fitted into Langmuir, Freundlich, and Temkin isotherm models. In addition, the pseudo-first-order, second-order, Elovich and the intraparticle diffusion model were applied to describe the adsorption kinetics of Cs. The results of the assessments indicated the adsorption experiments reached equilibrium very rapidly in 45 min. Furthermore, a maximum equilibrium adsorption capacity of 206 mgg−1 was obtained. The equilibrium data was fitted well with the Freundlich model, indicating that the Cs adsorption process was multilayered. Moreover, the pseudo-second-order kinetic model suitably described the kinetics of Cs adsorption. Desirable selectivity of Cs in the presence of the other interfering ions was confirmed. In addition, adsorption efficiency by the synthesized nanocomposite after five cycles reached 88% and determination of the thermodynamic parameters showed that the Cs adsorption process was endothermic and spontaneous. In addition, easy synthesis, high adsorption at ambient temperature, and wide ranges of pH are the other factors that make it a promising candidate for cesium removal.