Polanyi potential theory characteristic curve

The experimental verification of the Polanyi potential theory can be carried out by calculating the characteristic curve from one experimental isotherm and in determining from the characteristic curve the adsorption isotherms at any other temperature. It is essential that the basic isotherm used for obtaining the characteristic adsorption curve should cover the whole range of values and followed with great accuracy. 

Having calculated the curve characteristic for a given temperature it is possible to determine adsorption isotherms at other temperatures. The Polanyi potential theory does not give a definite equation of adsorption isotherm which, to some extent, replaces the characteristic adsorption equation. 

Dubinin was the pioneer of the concept of micropore filling. His approach was based on the early potential theory of Polanyi, in which the physisorption isotherm data were expressed in the form of a temperature-invariant characteristic curve . 

Experimental verification of the Polanyi theory deals with the calculation of the characteristic adsorption curve by means of an experimental isotherm and hence determination of the isotherms at different temperatures. The first practical examinations of the potential theory of adsorption carried out by Titoff [137] and Berenyi [138] showed the good agreement with experiment. 

Correlation of the experimental isotherms by a generalized one is encouraged by the possibility that if the generalized isotherm for a given adsorbate is known, the adsorption values at any temperature and pressure can be predicted. Such a representative generalized isotherm is the Dubinin-Polanyi characteristic curve. According to the potential theory, the plot of adsorbed volume versus adsorption potential is temperature independent and, hence, characteristic. The adsorbed volume is determined by [55]... 

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