Separation of Sr-90 and Ca2+ in Enviromental Samples

描述(申请人提供)：该SBIR项目的目标是开发一种对Sr2+具有极高选择性的改进型无机离子交换剂。这种离子交换器将改善从美国和世界各地因事故或核材料处理不当而受到污染的地下水中90锶的提取，其中一些核材料与含水层和用作饮用水供应的水体接触。~(90)Sr是一种放射性同位素，其最大安全暴露限值极低。(饮用水限制为8pci/L)这种材料的开发将为更安全的饮用水做出重大贡献。在这个项目的第一阶段，我们证明了用SnV和SilV取代焦绿石结构的锑酸(Sb2O5 4H2O)中的部分SBV，使该化合物对锶的亲和力和对锶的选择性比对钙的选择性提高了近四倍。(对锶+2的强烈偏好很重要，因为锶总是含有大量过剩的钙。)所产生的材料具有90锶的容量，是目前用于泵和处理系统中收集锶的斜发沸石的200多倍。在第二阶段，我们将改进交换剂的组成并扩大合成规模。该材料将经过详细评估，用作从地下水中提取90锶的柱材料，或用作可渗透反应屏障的活性成分，以阻止地下水中90锶的运动。简单地说：在锑酸中加入锡或硅极大地提高了它在存在非常相似的钙的情况下从水溶液中去除锶的能力。这使得它成为从地下水中去除放射性锶-90的极佳选择，无论是在地表还是在地下。

DESCRIPTION (provided by applicant): The goal of this SBIR project is the development of an improved inorganic ion exchanger with an extremely high selectivity for Sr2+. This ion exchanger will improve the extraction of 90Sr from groundwater at the sites around the US and the world that have become contaminated through mishap or poor handling of nuclear materials, some of which are in contact with aquifers and bodies of water used as drinking water supplies. 90Sr is a ?-emitting isotope with an extremely low maximum safe exposure limit. (The drinking water limit is 8 pCi/L.) Development of this material will make a significant contribution to safer drinking water. In Phase I of this project we demonstrated that the substitution of SnlV and SilV for part of the SbV in the pyrochlore-structured antimonic acid (Sb2O5 4 H2O) increased both the compound's affinity for Sr+2 and its selectivity for strontium over calcium by a factor of nearly four. (A strong preference for Sr+2 is important, because the strontium is always found with a large excess of calcium.) The resulting material has a capacity for 90Sr over 200 times that of the clinoptilotile currently used to collect strontium in pump-and-treat systems. In Phase II we will refine the composition of the exchanger and scale-up the synthesis. The material will be evaluated in complete detail for use as a column material for extracting 90Sr from ground water out of the ground or as the active component in a permeable reactive barrier to block the motion of 90Sr in ground water in the ground. In plain language: Adding tin or silicon to antimonic acid greatly improves its ability to remove strontium from aqueous solutions in the presence of the very similar calcium. This makes it an excellent choice for removing radioactive strontium-90 from ground water either at the surface, or while still in the ground.