Research On The Adsorption Performance Of Uranyl Ion By Three New Kinds Of Styrene-divinyl Benzene Ion-exchange Resin

The nuclear fuel cycle is an important part of the development of nuclear energy.In this cycle system,the post-treatment of spent fuel is a key factor to ensure the sustainable development of nuclear energy in China.It is well known that post-treatment can effectively improve the utilization rate of uranium resources,make full use of the current limited uranium resources,and make the radioactive toxicity of the ultimate waste be greatly reduced,so that the uranium can play a greater role in the development and utilization of nuclear energy.As a common enrichment and separation method of low-concentration uranium,the ion exchange method has a more general application value,and the synthesis and application of a novel high-efficiency adsorption material has become a booster for the rapid development of the method.In this paper,the influence of three kinds of ion-exchange resin＿D231YT ion-exchange resin,U400B resin and CLP204-extraction ion-exchange resin on the adsorption performance of low-concentration uranium by using styrene-divinylbenzene as a framework matrix and different functional groups is discussed.The following conclusions are obtained:（1）The optimum p H of the D231YT resin for uranium is 6.0,the adsorption amount is increased with the increase of the concentration of uranium in the solution and the adsorption capacity can reach 72.4 mg/g at 360 min,and the dynamic experiment shows that the adsorption capacity can reach 72.4 mg/g.When the standard solution of uranium reaches 75 times the volume of the resin bed,the adsorption tends to be balanced;in a plurality of eluates,the elution effect of the solution of 0.9 mol/L Na Cl+0.2 mol/L H₂SO₄ is the best,and the elution is completed when the volume of the eluted liquid reaches the volume of the resin bed of 20 times.The results show that the adsorption of D231YT ion-exchange resin to uranium is in accordance with the quasi-second-order kinetic model and the Langmuir-adsorption isotherm equation.The results of the thermodynamic study show that the adsorption process can increase the entropy and the spontaneous endothermic reaction in the temperature range of the experiment.（2）The adsorption of U（Ⅵ）by U400B resin showed that the optimum adsorption p H of U400B resin for U 400B resin was 8.0.the adsorption capacity increased with the prolongation of adsorption time and reached the adsorption equilibrium at 300 min.The adsorption capacity also increased with the increase of uranyl ion concentration in solution,and the adsorption capacity increased with the increase of temperature.In the dynamic experiment,when the standard solution of U reaches 90 times of the volume of resin bed,in a plurality of eluates,the elution effect of the solution of 60.0 g/L Na Cl+5.0 g/L H₂SO₄ is the best,and the elution is completed when the volume of the eluted liquid reaches the volume of the resin bed of 20 times.The results of kinetic study show that the adsorption of U400B ion exchange resin for U is in accordance with the quasi-second order kinetic model and Langmuir adsorption isotherm equation,which indicates that the adsorption of U（Ⅵ）by U400B ion exchange resin is mainly chemical adsorption and monolayer adsorption,and the thermodynamic results show that the adsorption process is entropy increasing and spontaneous endothermic reaction in the range of experimental temperature.（3）The adsorption of U（Ⅵ）by CLP204 extraction resin shows that the optimum p H for adsorption of U by CLP204 extraction resin is 5.0,and the adsorption capacity increases with the increase of adsorption time,and reaches the adsorption equilibrium at 240 min,and the saturated adsorption capacity is 92.4mg/g.The adsorption capacity increases with the increase of uranyl ion concentration in solution,and the adsorption capacity increases with the increase of temperature.The results of kinetic study show that the adsorption of uranium by CLP204 extraction resin accords with the quasi-second-order kinetic model and Langmuir adsorption isotherm equation,which indicates that the adsorption of（Ⅵ）by this resin is mainly chemical adsorption and monolayer adsorption,and the thermodynamic results show that the adsorption process is entropy increasing and spontaneous endothermic reaction in the range of experimental temperature.In summary,the adsorbents of D231YT ion exchange resin,U400B resin and CLP204 extraction resin for uranium（Ⅵ）have the advantages of good adsorption effect and good stability,and have good application value for the separation and recovery of uranium in low concentration system.However,compared with the other two resins,CLP204 extraction resin has the best adsorption effect on（Ⅵ）,which has the advantages of high saturated adsorption capacity,fast adsorption rate,little influence by temperature and high application value.