Recent advances in the development of amidoxime‐based adsorbents have made it highly promising for seawater uranium extraction. However, there is a great need to understand the influence of temperature on the uranium sequestration performance of the adsorbents in natural seawater. Here the apparent enthalpy and entropy of the sorption of uranium (VI) and vanadium (V) with amidoxime‐based adsorbents were determined in natural seawater tests at 8, 20, and 31 °C that cover a broad range of ambient seawater temperature. The sorption of U was highly endothermic, producing apparent enthalpies of 57 ± 6.0 and 59 ± 11 kJ mol⁻¹ and apparent entropies of 314 ± 21 and 320 ± 36 J K⁻¹ mol⁻¹, respectively, for two adsorbent formulations. In contrast, the sorption of V showed a much smaller temperature sensitivity, producing apparent enthalpies of 6.1 ± 5.9 and −11 ± 5.7 kJ mol⁻¹ and apparent entropies of 164 ± 20 and 103 ± 19 J K⁻¹ mol⁻¹, respectively. This new thermodynamic information suggests that amidoxime‐based adsorbents will deliver significantly increased U adsorption capacities and improved selectivity in warmer waters. A separate field study of seawater uranium adsorption conducted in a warm seawater site (Miami, FL, USA) confirm the observed strong temperature effect on seawater uranium mining. This strong temperature dependence demonstrates that the warmer the seawater where the amidoxime‐based adsorbents are deployed the greater the yield for seawater uranium extraction.

中文翻译：

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天然海水中铀和钒吸附对A胺肟基吸附剂的温度依赖性

基于mid胺肟类吸附剂的最新开发进展使其在海水铀萃取中具有广阔的前景。然而，非常需要了解温度对天然海水中吸附剂的铀螯合性能的影响。在此，在8、20和31°C的天然海水测试中确定了a胺肟基吸附剂对铀（VI）和钒（V）的吸附的表观焓和熵。U的吸附是高度吸热的，产生的表观焓为57±6.0和59±11 kJ mol ^-1，表观熵为314±21和320±36 JK ^-1 mol ^-1分别用于两种吸附剂配方。相反，V的吸附显示出较小的温度敏感性，产生的表观焓为6.1±5.9和-11±5.7 kJ mol ^-1，表观熵为164±20和103±19 JK ^-1 mol ^-1， 分别。这些新的热力学信息表明，基于mid胺肟的吸附剂将在温暖的水中显着提高U吸附能力并提高选择性。在温暖的海水场所（美国佛罗里达州迈阿密）进行的另一项海水铀吸附现场研究证实了观察到的强烈温度效应对海水铀开采的影响。这种强烈的温度依赖性表明，使用基于ox胺肟的吸附剂的海水温度越高，提取海水铀的产量就越高。