赋能动力学色谱法快速海水提铀研究

Energy-endowed kinetic chromatographic columns for rapid uranium extraction from seawater

作为重要的分离和分析手段,液相色谱法主要应用在分析化学领域,而在核素分离工作中报道十分罕见。本项目基于动力学色谱理论基础,研发出一种脉冲式进样-赋能动力学色谱柱,色谱柱的填料采用粒径为0.2 mm的惰性二氧化硅,柱长为5 m,色谱分离单元约3.06万个。通过改变色谱柱外界条件,分析铀酰离子在色谱柱内的运动情况;通过水浴加热、超声波和外加磁场对色谱柱进行赋能,以提高离子相互分离的效果;在不同进样流速和温度下,研究混合核素的分离情况,得到最佳分离条件及色谱柱的动力学特性。结果表明,样品流速为4.109 mL·min^(−1),色谱柱加热温度为50℃,此时铀酰离子和钠离子的分离因数为1.1854。以最佳分离条件进行海水提铀,得到铀和钠离子的分离因数为α=1.575,实现海水中铀和钠离子分离理论上需要20级。脉冲式进样-赋能动力学色谱柱能够高效快速地实现海水中铀的分离提取。文中采用的创新性方法,还可应用于其他核素的分离研究。

[Background]With the continuous development of society and economy,nuclear energy has emerged as a crucial solution to address global energy shortages.However,uranium reserves on land have diminished after nearly half a century of extraction,resulting in irreversible harm to the natural environment.Consequently,seawater uranium extraction has become a more eco-friendly and abundant source of uranium resources,compared to terrestrial uranium mining.And extracting uranium from seawater emerges as a prudent strategy.[Purpose]This study aims to use kinetic chromatography to extract uranium from seawater and investigate the separation mechanism.[Methods]Leveraging the concepts of dynamic chromatography,a pulsed-injection energy-endowed kinetic chromatography column was developed.The column utilized spherical SiO2 with a diameter of 0.2 mm and a length of 5 m as the filler.After filling,it encompassed approximately 30600 chromatographic separation units.A peristaltic pump for pulse injection was applied to the kinetic chromatography system,and a switching pulse injection device was equipped to enable time control splitting.Subsequently,a self-developed on-line spectrophotometric detector was utilized to monitor the concentration of target components in the solution in real-time so as to avoid human control errors during multistage separation experiments.Additionally,the behavior of uranyl ions in kinetic chromatography under varying conditions and determine the best separation conditions was investigated by experiments using different mobile phase carriers,pH values,injection flow rates,energy-endowed modes,and energy-endowed series,and various energy-endowed methods,including water bath heating,ultrasonic,and external magnetic fields,were employed to achieve optimal separation conditions.Finally,the separation factor of uranium and sodium ions in actual seawater uranium extraction was calculated to explore the separation mechanism by separate studies of uranium,europium,and sodium ions,as well as an actual seawater uranium extraction.[Result]Results of this series of studies demonstrates that the best separation effect is achieved when using hydrochloric acid as the mobile phase carrier in dynamic chromatography,with a pH of 2,a sample flow rate of 4.109 mL·min^(−1),water bath heating as the energy-endowed mode,a heating temperature of 50℃,and a heating series of 4.Under these optimal conditions,the separation factor between uranium and sodium ions can reach 1.1854 in the separation studies of uranium,europium and sodium ions.In the real seawater uranium extraction study,the separation factor between uranium and sodium ions can reach 1.575.After simulation and calculation,the theoretical separation of uranium and sodium ions in seawater requires a minimum of 20 levels.[Conclusions]The efficient and rapid extraction and separation of uranium from seawater is facilitated in this study using a pulsed-injection energy-endowed kinetic chromatography column.This separation strategy allows for the efficient separation of light and heavy particles without interaction of the mobile and stationary,resulting in a high sample recovery rate and no need for column regeneration.This technique has potential for the separation of other nuclides,making it a versatile tool for nuclear chemistry research.