A Correlation Method in Studying Chemisorption Processes on Uniformly Inhomogeneous Surfaces

Abstract

Chemisorption processes taking place on uniformly inhomogeneous surfaces in the presence of entropic inhomogeneity are examined. A new form of linearity relationship connecting the current rate and the equilibrium constant at definite degrees of surface coverage is derived. The relationship can be applied to complex chemisorption processes when determination of the rate constant is impossible. Linear correlations between the activation energy and the adsorption enthalpy, as well as between the entropy characteristics and pre-exponential factors, are obtained. The complex effect of the energy and entropy factors on the kinetics and the equilibrium is discussed theoretically and verified experimentally. These factors operate through a thermodynamic and a kinetic compensation effect. The present paper illustrates the correlation methods employing experimental results derived from the study of the chemisorption of the optical brighteners Leucophor AP and Tinopal UP onto pulp, of Fe 3+ and Cu 2+ ions onto fibrous polyampholyte and of hydrolysis-modified polyacrylonitrile (HMP) onto pulp.