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首页> 外文期刊>Separation and Purification Technology >Development of a model surface flow membrane by modification of porous #gamma#-alumina with octadecyltrichlorosilane
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Development of a model surface flow membrane by modification of porous #gamma#-alumina with octadecyltrichlorosilane

机译：通过用十八烷基三氯硅烷改性多孔＃γ＃氧化铝来开发模型表面流膜

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Novel organic/inorganic gas-separation membranes were fabricated by modification of mesoporous #gamma#-alumina ultrafilters with octadecyltrichlorosilane (ODS). bawed on ellipsometry measurements and XPS analysis, our hypothesis is that the membranes were composed of a very thin, approximately 11 nm, layer of ODS oligimers grafted to the surface of the mesoporous substrate. However, the microstructure of the silane layer is not well understood. Pure gas permeance of the alumina membrane decreased by 2 to 3 orders of magnitude after modification with ODS. Permeance was flowing N_2 with a pressure drop across the membrane of approximately 34.5 kPa. Folowing silane modification the membrane exhibited reverse selectivity, or selectivity for heavier gases such as CO_2 and n-C_4H_(10), over lighter gases such as H_2, N_2 CH_4 and C_2H_6. Reverse selectivities were measured as high as 48 for n-C_4H_(10)/N_2 and 24 for n-C_4H_(10)/CH_4. The pure gas permeance of various gases fit an exponential relationship with critical temperature that was consistent with transport based on preferential sorption and solution diffusion often observed in rubbery polymers. A model for surface diffusion enhanced permeation provided a parametric fit to the pure gas permeance of the ODS membrane. A maximum in permeance as a function of pressure and temperature, and a change in sign for the apparent activation energy of diffusion, distinguished the sporption and surface flow of n-C_4H_(10) from the transport of non-condensable gases and CO_2.
机译：新型有机/无机气体分离膜是通过用十八烷基三氯硅烷（ODS）改性介孔＃gamma＃-氧化铝超滤膜制成的。在椭圆偏振光测量和XPS分析的基础上，我们的假设是膜是由非常薄的大约11 nm的ODS低聚物层组成的，该层接枝到中孔基质的表面上。但是，硅烷层的微观结构还没有被很好地理解。用ODS改性后，氧化铝膜的纯净气体渗透率降低了2-3个数量级。渗透液流过N_2，整个膜的压降约为34.5 kPa。进行硅烷改性之后，该膜相对于较轻的气体（如H_2，N_2 CH_4和C_2H_6）表现出反向选择性，或对较重的气体（如CO_2和n-C_4H_（10））的选择性。对n-C_4H_（10）/ N_2测得的反向选择性高达48，对于n-C_4H_（10）/ CH_4则高达24。各种气体的纯气体渗透率与临界温度之间呈指数关系，这与基于橡胶状聚合物中经常观察到的优先吸附和溶液扩散引起的传输一致。表面扩散增强渗透的模型为ODS膜的纯气体渗透提供了参数拟合。渗透率的最大值与压力和温度的函数关系以及表观扩散活化能的符号变化将n-C_4H_（10）的吸收和表面流与不可冷凝气体和CO_2的传输区分开来。

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