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 1340.    HALSEY, G. D.  Physical Adsorption on Nonuniform Surfaces.  Jour. Chem. Phys., vol. 16, 1948, pp. 931-937; Chem. Abs., vol. 42, 1948, p. 8,573.

       Analysis of adsorption on a uniform surface by using the quasichemical theory of interaction shows that the hypotheses of the Brunauer-Emmett-Teller theory lead to substantially no adsorption beyond the first layer if E₂=E_L, and stepwise isotherms if E₁>E₂>E₃ · · · >E_L.  For the monolayer adsorption of gases on Ag, Pt, and steel, the heterogeneous nature of the adsorbing surface is clearly indicated.  Cooperative adsorption on the nonuniform surface is treated and the cooperative analog of the Freundlich equation derived.  The typical multilayer isotherm is shown to be composed of 3 regions:  Noncooperative adsorption on a strongly heterogeneous surface; cooperative adsorption on a still heterogeneous surface; and cooperative multilayer adsorption induced by small van der Waals perturbations some distance from the surface.  The isotherm p/p_o=experiment (-a/O^T) is derived and shown to be a good representation of adsorption data that conform to the Brunauer-Emmett-Teller type I, II, or III shapes.