| 摘要 |
PURPOSE:To certainly measure the concn. distribution in a separation membrane, by calculating the adsorbing layer corresponding to the vapor pressure of a permeable substance at definite temp. with respect to the separation membrane and detecting the concn. distribution of the permeable substance in the separation membrane on the basis of the relation with the vapor pressure in the separation membrane. CONSTITUTION:For example, a dense uniform membrane having a thickness of 25mum composed of cellulose acetate with an acetylation degree of 54.4% is used as a separation membrane, and water and ethanol are separately used as permeable substances. The transmission flow rate in a steady state to the pressure of 0-150mmHg on a transmission side at 40 deg.C is measured by collecting transmitted gases by a cold trap. In the saturation vapor pressure (water: 55mmHg, ethanol: 130mmHg) of each permeable substance at 40 deg.C, change is confirmed in a transmission mode. Subsequently, this relational curve is inversely transformed and made dimensionless to calculate the vapor pressure distribution of each permeable substance in the cellulose acetate membrane and the respective definite relative vapor pressures of water (A) and ethanol (B) are adjusted and the increase in the wt. of the separation membrane is measured to make it possible to calculate the adsorption isothermal line shown by a drawing and each concn. distribution can be clearly measured.
|
