Nickel-doped silica membranes for separation of helium from organic gas mixtures
Nickel-doped silica membranes for separation of helium from organic gas mixtures
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DOI：
10.1081/ss-200041989
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发表时间：
2005-01-01
影响因子：
2.8
通讯作者：
Asaeda, M
中科院分区：
文献类型：
--
作者：
Kanezashi, M;Fujita, T;Asaeda, M
使用无机二氧化硅膜的问题之一是它们对水或水蒸气的不稳定性，这是由二氧化硅网络的溶解和重排引起的问题。在这项工作中，将Ni(NO3)(.)6H(2)O添加到硅溶胶中，通过溶胶-凝胶技术制备Ni掺杂二氧化硅膜，以防止无定形二氧化硅网络在50-300℃的潮湿气氛中致密化。在 500℃ 下烧制的新鲜 Ni 掺杂二氧化硅膜 (Si/Ni = 2/1) 在 300℃ 下表现出约 2.6 x 10(-5) [m(3) (STP) /(m(2) (.) s (.) kPa)] 的大 He 渗透性，选择性为 600 (He/CH4)。 Ni掺杂二氧化硅膜在潮湿空气（40℃，60％RH）中放置4天后，He渗透率略有下降（5％），300℃时选择性较高，为800（He/CH4）。然而，He 渗透的活化能几乎没有观察到变化，这表明添加到二氧化硅中的镍氧化物可以更好地防止二氧化硅网络的致密化，只有 H-2 和 He 可以渗透。潮湿的 He 和 CH4 显示出比干燥气体更小的渗透率，特别是在低于 150°C 的温度下，这是因为二氧化硅网络和晶界上有冷凝和/或吸附的 H2O 分子。在 300°C 下用新鲜的 Ni 掺杂二氧化硅膜 (Si/Ni = 2/1) 分离 He/CH4 混合物得到了相对较好的结果，并且与理想渗透率比 600 的预测值非常吻合。
One of the problems in the use of inorganic silica membranes is their instability against water or water vapor, a problem that results from the dissolution and rearrangements of silica networks. In this work Ni(NO3)(.)6H(2)O was added to silica sol for fabrication of Ni-doped silica membranes by sol-gel techniques in order to prevent the densification of amorphous silica networks in a humid atmosphere at 50-300degreesC. A fresh Ni-doped silica membrane (Si/Ni = 2/1) fired at 500degreesC showed a large He permeance of about 2.6 x 10(-5) [m(3) (STP) /(m(2) (.) s (.) kPa)] with a selectivity of 600 (He/CH4) at 300degreesC. After the Ni-doped silica membrane was left in humid air (40degreesC, 60% RH) for 4 days, the He permeance decreased slightly (by 5%) with a larger selectivity of 800 (He/CH4) at 300degreesC. However, little change was observed in the activation energy of He permeation, suggesting that nickel oxides added to silica can preferably prevent the densification of silica networks through which only H-2 and He can permeate. Humid He and CH4 showed smaller permeabilities, especially at temperatures below 150degreesC, than those of dry gases because of condensed and/or adsorbed H2O molecules in silica networks and on grain boundaries.Separation of He/CH4 mixtures with the fresh Ni-doped silica membrane (Si/Ni = 2/1) at 300degreesC gave relatively good results and coincided well with the predicted values with the ideal permeance ratio, 600.