Transport in ideal systems

Graham smdied the transport of gases through rubber membranes in 1861 and postulated the existence of a soludon-difiiision mechanism. The same approach is followed here where it is assumed that ideal sorption and diffusion behaviour occur. 

The solubility of a gas in a membrane can be described by Henry s law which indicates that a linear relationship exists between the external pressure p and the concentration c inside the membrane, i.e. 

The pressure is p i on the feed side (x = 0) and the penetrant concentration in the polymer is C, whereas on the permeate side (x = 6) the pressure is pi and the penetrant concentrarion is C2- Substitution of eq. V - 104 into Pick s law (eq.V - 84) and integrating across the membrane leads to  

Critical temperature Tg ami the solubility coefficient S of various gases in natural rubber [17] 

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