Synthesis, Characterization Of Carbon-based Supramolecular Hybrid Materials And Their Adsorption Properties Of Cs(?)

Separation and enrichment of radionuclide cesium in high-level liquid waste?HLLW?is an one of the key problems to be solved urgently in treatment of radioactive waste.In this paper,a column chromatography extraction method based on carbon-based supramolecular hybrid materials was proposed based on the shortcomings of solvent extraction method.In this method,the millimeter macro-mesoporous carbon spheres?MMCs?are utilized as the carrier for the extractant,then styrene and a alkenylCalix[4]Crown6 were co-polymerized after impregnated into pore of MMCs.TwoalkylCalix[4]Crown6derivatives?i.e.,propenyCalix[4]Crown6and butenylCalix[4]Crown6?were designed and synthesized by nucleophilic substitution,Williamson etherification and Inverse Friedel-Crafts reaction.The intermediate and final products in each step of synthetic route were characterized by ¹H NMR and elemental analysis to determine their structure.MMCs were prepared by reverse emulsion dispersion method and solvent evaporation self-assembly method with m-diphenol and furfural.The surface morphology and pore structure was characterized by SEM and N₂-BET method,respectively.AlkylCalix[4]Crown6 and styrene were loaded into carbon spheres by vacuum solvent evaporation and then in situ polymerized.Structural characterization of carbon-based supramolecular hybrid material p-Calix[4]Crown6/MMCs was carried out by means of SEM,¹H NMR and N₂-BET method.The results showed that the alkenylCalix[4]Crown6and styrene were successfully polymerized and loaded into MMCs's hole wall.The effects of nitric acid concentration,contact time,temperature,coexistence ion and Cs?I?concentration on the adsorption of Cs?I?on p-Calix[4]Crown6/MMCs were investgated by batch experiments.The adsorption kinetic were analysed by pseudo-first-order and second-order kinetic and intraparticle diffusion model.The adsorptive isotherms were analysed by Langmuir and Freundlich equations.The entropy change??S^o?,enthalpy change??H^o?and Gibbs free energy change??G^o?were calculated by the fitting curve of thermodynamic functions.The optimal nitric acid concentration is determined to be 3 mol/L for both p-Calix[4]Crown6/MMCs.The equilibrium time for p-propenyCalix[4]Crown6/MMCs and p-butenylCalix[4]Crown6/MMCs is 160 min and140 min respectively.The adsorption isotherm conformed to Langmuir isotherm adsorption model for both p-Calix[4]Crown6/MMCs.The adsorption process is an exothermic and spontaneous process for both pCalix[4]Crown6/MMCs.The above results showed that the p-propenyCalix[4]Crown6/MMCs and p-butenylCalix[4]Crown6/MMCs can effectively and remove cesium from solution selectively.This study can provide theoretical and experimental support for the removal of cesium from high-level liquid waste.