He jishu (Feb 2024)
Energy-endowed kinetic chromatographic columns for rapid uranium extraction from seawater
Abstract
BackgroundWith 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.PurposeThis study aims to use kinetic chromatography to extract uranium from seawater and investigate the separation mechanism.MethodsLeveraging 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 30 600 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.ResultResults 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 1.185 4 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.ConclusionsThe 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.
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