用甲基三乙氧基硅烷(MTES)代替部分正硅酸乙酯(TEOS)作为前驱物,通过共水解缩聚反应可制得甲基修饰的二氧化硅膜.通过TGA、FTIR以及气体渗透等测试手段对甲基修饰的SiO2膜进行研究,发现随着MTES/TEOS摩尔比例的增大,二氧化硅膜的憎水性能逐渐增强,当MTES/TEOS达到0.8时,二氧化硅膜的孔表面几乎不再吸附水气.氢气在MTES/TEOS为1的支撑体二氧化硅膜的输运受温度的控制,200℃时H2的渗透率达到6.0×10-7mol·m-2.Pa-1·s-1,H2/CO2分离系数达到6.0,于200℃以及水蒸气压力为3564Pa的环境中陈化近110h后H2渗透率基本保持不变,H2/CO2分离系数有所增大,说明经过甲基修饰的二氧化硅膜比纯二氧化硅膜具有更好的水热稳定性.
Methyl-modified silica membranes were prepared by acid catalysed co-hydrolysis and condensation reaction of
tetra-ethylortho-silicate(TEOS) and methyl-tri-ethoxy-silane(MTES) in ethanol and characterized by TGA,FTIR and gas permeation. The hydrophobicity of
modified silica membranes increases with MTES/TEOS molar ratio and almost no water can be adsorbed on the surface of the membranes with MTES/TEOS
molar ratio higher than 0.8. For the modified silica membranes with METS/TEOS molar ratio of 1, the hydrogen transport is activated by temperature
with a H2 flux of 6.0×10-7mol·m-2·Pa-1·s-1 and H2/CO2 separation factor of 6.0 at 200℃, and the hydrogen
permeance shows little change and the H2/CO2 separation factor increases after aging at 200℃ and a water vapor pressure of 3564Pa
for 110 hours. It’s shown that CH3-modified silica membranes are more hydrothermally stable than the unmodified silica membranes.
参考文献
| [1] | |
| [2] | Imai H, Morimoto H, Tominaga A, et al. J. Sol-gel Sci. & |
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