Decommissioning Technology Research Division, Korea Atomic Energy Research Institute, 989-111 Daedukdaero, Yuseong, Daejeon, 34057, Republic of Korea; Quantum Energy Chemical Engineering, University of Science and Technology (UST), 217, Gajeong-ro, Daejeon, 34113, Republic of Korea.
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
Chemosphere. 2022 Jul;299:134309. doi: 10.1016/j.chemosphere.2022.134309. Epub 2022 Mar 23.
Selective removal of radioactive strontium (Sr) from the environment is important, and selective adsorption/ion exchange is appropriate for removal of trace amounts of Sr from large volumes of Sr-contaminated water. Although various inorganic ion-exchange materials, including zeolites, have been investigated intensively for removal of Sr due to their excellent resistance to radiation and high ion-exchange capacity, their ion-exchange selectivity for Sr is poor in the presence of competing ions such as Ca and Mg. Here, sulfur-modified NaA zeolite (S-NaA) was prepared for low-cost, selective Sr removal because the elemental sulfur encapsulated in micropores provides additional Lewis acid-base interactions with Sr during the Sr ion-exchange. Our ion-exchange experiments revealed that S-NaA with 3 wt% sulfur (3 S-NaA) showed the highest Sr selectivity among various S-NaAs containing up to 10 wt% sulfur because ion exchange involving bulky hydrated Sr depends on the reduced micropore volume of S-NaA after sulfur loading. Most importantly, 3 S-NaA effectively and efficiently (>99.4%) removed Sr from groundwater containing 8.4 ppt Sr, demonstrating its excellent potential for practical application in the treatment of Sr-contaminated water.
从环境中选择性地去除放射性锶（Sr）很重要，而选择性的吸附/离子交换适合于从大量含有 Sr 的污染水中去除痕量的 Sr。尽管各种无机离子交换材料，包括沸石，由于其对辐射的优异抗性和高离子交换容量，已经被广泛研究用于去除 Sr，但在存在竞争离子如 Ca 和 Mg 的情况下，它们对 Sr 的离子交换选择性很差。在这里，硫改性的 NaA 沸石（S-NaA）被制备用于低成本、选择性地去除 Sr，因为包裹在微孔中的元素硫在 Sr 离子交换过程中提供了与 Sr 的额外的路易斯酸碱相互作用。我们的离子交换实验表明，含有 3wt%硫的 S-NaA（3S-NaA）在含有高达 10wt%硫的各种 S-NaA 中表现出最高的 Sr 选择性，因为涉及大体积水合 Sr 的离子交换取决于硫负载后 S-NaA 的减少的微孔体积。最重要的是，3S-NaA 有效地、高效地（>99.4%）从含有 8.4ppt Sr 的地下水去除 Sr，证明了其在处理 Sr 污染水方面的实际应用的巨大潜力。
