Molecular-sieving effect of zeolite 3A on adsorption of H2, HD and D2
Molecular-sieving effect of zeolite 3A on adsorption of H2, HD and D2
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DOI：
10.1016/j.fusengdes.2009.01.052
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发表时间：
2009-06-01
影响因子：
1.7
通讯作者：
Nakamura, Y.
中科院分区：
文献类型：
--
作者：
Kotoh, K.;Takashima, S.;Nakamura, Y.
合成沸石3A的晶格骨架中具有标称直径为0.3 nm的分子筛窗，阻碍直径大于0.3 nm的分子的晶体吸附，水、氢和氦除外。然而，窗口的直径随温度略有变化，实验结果证实氢在液氮温度下不能被吸附。作者测量了3A沸石允许氢吸附的温度范围，并揭示了H-2和D-2分子筛出现时几度的温差。这种差异很重要，因为如果在分子筛出现温度之间调节的温度下操作，则可以通过吸附从 H-2-D-2 混合物中分离出一种同位素。我们报道了从分子筛实验中获得的 D-2/H-2 分离因子的大值。在本研究中，使用 H-2-HD-D-2 混合物检查了混合原子同位素 HD 的筛分效果。我们在这里报告了在 D-2/H-2 因子和统一因子之间评估的实验 HD/H-2 分离因子。这个结果很重要，因为其中提出了与筛分机制有关的有效分子直径。根据这些知识，可以预测 HT 和 DT 筛分的同位素效应。 (C) 2009 Elsevier B.V. 保留所有权利。
Synthetic zeolite 3A has the molecular-sieving windows of nominal diameter 0.3 nm in its crystal lattice framework, which obstruct the crystalline adsorption of molecules of diameter larger than 0.3 nm, except water, hydrogen and helium. The window's diameter slightly varies with temperature, however, that is endorsed in experimental results that hydrogen cannot be adsorbed at the liquid-nitrogen temperature. Authors measured the range of temperature where zeolite 3A permits hydrogen adsorption, and revealed the temperature difference of several degrees in appearance of molecular sieving for H-2 and D-2. This difference is important because from a H-2-D-2 mixture one isotope could be isolated by adsorption if operated at a temperature regulated between the molecular-sieving appearance temperatures. We have reported large values of D-2/H-2 separation factor obtained from molecular-sieving experiments. In this study, the effect of sieving for the hybrid-atomic isotope HD is examined using a H-2-HD-D-2 mixture. We here report the experimental HD/H-2 separation factor evaluated between the D-2/H-2 factor and unity. This result is significant because where the effective molecular diameter concerning the sieving mechanism is suggested. From this knowledge, the isotopic effect of sieving for HT and DT can be predicted. (C) 2009 Elsevier B.V. All rights reserved.