Adsorption and separation behavior of uranium(VI) by 4-vinylpyridine-grafted-vinyltriethoxysilane-cellulose ion imprinted polymer

• A novel adsorbent, U(VI)-IIP, was synthesized by ion imprinting technique.
• 4-vinyl pyridine is used as functional monomer and uranyl ion as template.
• Adsorption characteristics of U(VI) onto U(VI)-IIP were investigated.
• Utility and regeneration studies of U(VI)-IIP were carried out.
• U(VI)-IIP is effective for the removal of U(VI) from aqueous solutions.

The current paper presents the synthesis of a novel ion imprinted polymer [U(VI)−IIP], by bulk polymerization method using 4-vinylpyridine as a functional monomer, ethylene glycol dimethacrylate as a crosslinker and 2,2′-azobisisobutyronitrile as an initiator, and its application for the selective adsorption of uranium(VI) ions from aqueous solutions. A non imprinted polymer (NIP) was also prepared under identical experimental conditions without using UO22+ ions. All the synthesized polymers were characterized using Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. U(VI)-IIP showed higher capacity and selectivity for U(VI) than the NIP. Various parameters such as solution pH, initial concentration, sorbent dosage and rate of adsorption were investigated using batch adsorption experiments. The optimum pH was found to be 7.0. Kinetic studies indicated that pseudo-second-order kinetic model best describes the adsorption behavior. The adsorption isotherms were found to be consistent with Langmuir adsorption isotherm and the equilibrium sorption capacity was estimated to be 133.95 mg/g at 30 °C. The thermodynamic parameters calculated from the adsorption data suggested that the adsorption of U(VI) onto U(VI)-IIP was a spontaneous and endothermic nature of process. The prepared U(VI)-IIP was successfully used to extract U(VI) from simulated nuclear industry effluents with an adsorbent dosage of 2.5 g/L. The distribution ratio and selectivity coefficients of UO22+ ions and other selected metal ions on U(VI)-IIP were also evaluated. Adsorbed U(VI) ions were effectively desorbed using 0.1 M HCl. The present investigation revealed that U(VI)-IIP is a promising adsorbent for the removal and recovery of U(VI) from aqueous solutions.

Figure optionsDownload as PowerPoint slideA novel ion imprinted polymer, U(VI)-IIP for the selective separation of U(VI) from aqueous solutions.