Development of bismuth-mordenite adsorbents for iodine capture from off-gas streams
Development of bismuth-mordenite adsorbents for iodine capture from off-gas streams
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DOI：
10.1016/j.cej.2019.123583
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发表时间：
2020-07-01
影响因子：
15.1
通讯作者：
Rezaei, Fateme
中科院分区：
文献类型：
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作者：
Al-Mamoori, Ahmed;Alsalbokh, Mansour;Rezaei, Fateme
寻找高效、廉价和坚固的吸附材料，以有效地从乏燃料后处理设施的废气流中去除碘化合物，仍然具有挑战性。在此，我们报道了铋掺杂丝光沸石的发展，具有不同的负载去除核废料废气流中的碘-129 （I-129）。在所研究的材料中，铋含量为5wt %的铋丝光沸石（Bi-5@Mordenite）在200℃下暴露于碘6小时后表现出最高的捕获能力，碘吸收能力高达538 mg/g，与动力学相对较快的裸丝光沸石相比，其捕获能力高出2.5倍。有趣的是，由于掺入铋过程中丝光沸石的脱铝作用，掺入铋的丝光沸石样品比裸沸石样品具有更高的表面积和孔隙度。此外，还进行了浸出试验，以确定负载碘的Bi-5@Mordenite在与去水接触后的碘浸出程度，结果表明，在暴露24 h后，吸附剂中碘的最大释放量为36%，突出了将负载碘的吸附剂转化为适合永久地质处置的废物形式的必要性。总的来说，铋基沸石对碘的高吸收能力和快速吸收速率揭示了铋基沸石作为碘捕获材料在固化成废物形式进行长期衰变储存时的潜在效用。
The search for efficient, cheap, and robust sorbent materials which can effectively remove iodine compounds from off-gas streams in used nuclear fuel reprocessing facilities is still challenging. Herein, we report the development of bismuth-doped mordenite zeolite with different loadings for removal of iodine-129 (I-129) from nuclear waste off-gas streams. Of the materials investigated, bismuth-mordenite with 5 wt% bismuth content (Bi-5@Mordenite) exhibited the highest capture capacity with an iodine uptake capacity up to 538 mg/g after exposure to iodine for 6 h at 200 degrees C, which was similar to 2.5 times higher than that of the bare mordenite with relatively fast kinetics. Interestingly, the bismuth-doped mordenite sample exhibited higher surface area and porosity than those of the bare zeolite as a result of mordenite dealumination during bismuth incorporation. Moreover, the leach tests were carried out to determine the degree of iodine leaching from the iodine-loaded Bi-5@Mordenite upon coming into contact with DI water and the results revealed a maximum iodine amount of 36% that was released from the adsorbent after 24 h exposure, highlighting the necessity of transforming the iodine-loaded adsorbent into a suitable waste form for permanent geological disposal. Overall, the high uptake capacity and fast uptake rate of iodine reveal the potential utility of bismuth-based zeolites as iodine capture materials when consolidated into a waste form for long-term decay storage.