Ono-Kondo equation

Numerous efforts have been made to explain the abnormal behavior of supercritical adsorption isotherms and several theories were proposed. Overheated liquid [9] or quasi-hquid [10] conceptions were used to model the supercritical adsorption isotherms on the basis of the theory available for vapors. However, isotherms with maximum cannot be described in this way. The model based on the Ono-Kondo equation [11] was able to predict an isotherm with maximum, but its parameters were found to be unrealistic from the physical viewpoint [12]. Models based on the equation of state [13] and density functional theory [14] can satisfactorily describe the experimental adsorption isotherms. However, the number of parameters in such models is much larger than 3, the usual number of parameters in conventional isotherm equations. In fact, the multiple model parameters cannot provide the required information about adsorbents regarding their specific surface area, pore-volume and pore size distribution as it was usually done with conventional isotherm models. 

The definition of surface tension y for a spherical interface can be defined by the Bakker equation (after Ono Kondo 1960 and Buff 1955)... 

So far the arguments of this section have been mechanical or quasi-thermodynamic in the sense of 2.5. They lead to statistical mechanical results when we insert into these equations one of the expressions of 4.3 for the pressure tensor. Ono and Kondo choose the form due to Irving and Kirkwood, (4.99), and extract pr(r) from (4.203)... 

The individual variants of the lattice model differ fi om each other in the way the spatial distribution of the molecules of the individual components is taken into account. The simplest solution is the Bragg-Williams (B-W) approach which assumes a random distribution of molecules within the bulk phase. The thermodynamical meaning of this assumption is that the mixture is regular. In the adsorption layer, however, it is only in two dimensions (i.e., within the individual sublayers that a statistical distribution of molecules is assumed). Pioneering work in this field was published by Ono [92-94] and Ono and Kondo [95,96]. The method was later applied to the description of L/G interfaces by Lane and Johnson [97] and later taken up by Altenberger and Stecki [98]. Analytic isotherm equations have also been derived from the above... 

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