Transport mechanisms of water and organic solvents through microporous silica in the pervaporation of binary liquids
Transport mechanisms of water and organic solvents through microporous silica in the pervaporation of binary liquids
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DOI：
10.1016/j.micromeso.2003.08.010
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发表时间：
2003-11
影响因子：
5.2
通讯作者：
J. E. Elshof;Cristina Rubio Abadal;J. Sekulić;S. R. Chowdhury;D. Blank
中科院分区：
文献类型：
--
作者：
J. E. Elshof;Cristina Rubio Abadal;J. Sekulić;S. R. Chowdhury;D. Blank
渗透蒸发实验在30-80 °C的温度范围内使用含有5-22重量%的二进制液体在微孔二氧化硅膜上进行。水使用的有机溶剂是甲醇、N，N-二甲基甲酰胺（DMF）和1，4-二氧六环。考察了温度和进料组成对通量和选择性的影响。根据Maxwell-Stefan理论解释了结果，并估计了60 °C下的Maxwell-Stefan扩散系数。水，甲醇和DMF被发现通过表面扩散机制扩散通过二氧化硅，而1，4-二氧六环主要是通过粘滞流通过介孔或小缺陷传输。DMF抑制了水的运输，这可能是由于强吸附的DMF分子阻碍了水的运输。甲醇的通量似乎是由较大的水通量的拖曳效应占主导地位。
Pervaporation experiments were performed on microporous silica membranes in the temperature range 30–80 °C using binary liquids containing 5–22 wt.% water. The organic solvents used were methanol, N,N-dimethylformamide (DMF) and 1,4-dioxane. The dependency of flux and selectivity on temperature and feed composition were investigated. The results were interpreted in terms of the Maxwell–Stefan theory, and Maxwell–Stefan diffusion coefficients at 60 °C were estimated. Water, methanol and DMF were found to diffuse through silica by a surface diffusion mechanism, while 1,4-dioxane was transported mainly by viscous flow through mesopores or small defects. DMF inhibited the transport of water, which may be explained by micropore blocking by strongly adsorbed DMF molecules. The flux of methanol appears to be dominated by a dragging effect by the larger water flux.