Gas Liquid Equilibrium Method Permporometry

Permporometry is the only method suitable for the determination of the size distribution of the active pores with diameters ranging from about 1.5 nm to 0.1 pm in porous media, particularly those with an asymmetric (and/or composite) structure. Permporometry, a relatively new technique, is based on the controlled blocking of the pores by capillary condensation and simultaneous measurement of the gas diffusional flux through the remaining open pores [86]. There are two different approaches of the method. 

This method is commonly used to determine pore sizes and the pore size distributions of a membrane because it is close to UP filtration practice dead-end pores are not evaluated. The membrane is characterized in wet conditions. In this technique, the pressure is kept as low as possible and thus no alteration of the membrane occurs. 

With this technique, the permeation rate is measured at various transmembrane pressures and used to calculate pore-size distribution. Thus, this technique is the extension of the bubble point method. 

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