Preparations Of Beta-cyclodextrin Derivative And Their Enrichment And Seperation Behaviors For U(?)in Aqueous Phase

With the rapid development of the international economic and the increasing lack of energy resources,nuclear energy being a kind of green and efficient energy plays a significant role in not only civil industry but also military industry.As one of the core raw materials in the nuclear industry,it is important that research and develop new useful functional materials to separate and enrich uranium as well as study the adsorption behavior characteristics during the purification process.In this study,according to the free radical polymerization mechanism four functional beta-cyclodextrin derivative such as amidoxime linear-linked beta-cyclodextrin/acrylo-nitrile/acrylic terpolymer,amidoxime cross-linked beta-cyclodextrin/acrylonitrile/acr-ylic terpolymer,citric acid cross-linked polybeta-cyclodextrin and amidoxime citric acid cross-linked beta-cyclodextrin and acrylonitrile-acrylic block copolymer were synthesized by using the green,cheap and easily modified beta-cyclodextrin.And properties of beta-cyclodextrin derivative were charactered by FT-IR,SEM,NMR,TGA and element analysis.In this paper,by using the instruction method the influences of the solid liquid ratio of the adsorbents,ionic strength,pH,contact time,initial concentration of U(?)and adsorption temperature during the adsorption process were explored.At the same time the selectivity of the four kinds of beta-cyclodextrin derivatives for adsorbing U(?)and the reasonable desorption conditions were studied as well.It was found that the four adsorptions of beta-cyclodextrin derivatives and U(?)were all fast processes submitting to the pseudo-second-order model,which indicated that the four adsorptions were fast chemical processes.The result also indicated that the four beta-cyclodextrin derivative of U(?)adsorptions submitted to the Langmuir model,which proved that the four were homogeneous and unilaminar chemical process meanwhile the beta-cyclodextrin derivative and U(?)formed the surface complexes.In addition,among the four materials,the process of l-CD-AO-AA adsorbing U(?)had the fastest adsorption rate and the largest adsorption capacity,but the process of CD-AO-b-AA adsorbing U(?)had the poorest adsorption effect.The results of the thermodynamic parameters?G~0,?H~0 and?S~0,showed that the adsorption processes of four polymers are all endothermic chemical reactions,which means increasing the temperature can promote the adsorption of U(?).At the same time the four polymers can selectively adsorb the U(?)while there are some co-existing ions with the same initial concentration under pH=4.00±0.05,among which l-CD-AO-AA has the best selectivity while CD-AO-b-AA is the poorest one.In the mean time,the U(?)could be effectively desorbed from the beta-cyclodextrin derivatives under the low acidity.The desorption ratios of l-CD-AO-AA and c-CD-AO-AA could attained95%as well as the derivatives PCD and CD-AO-b-AA could reached 80%.All the above shows that l-CD-AO-AA and c-CD-AO-AA have a much more promising application prospect for seperation of U(?).