ADSORPTION IN PORES WITH HETEROGENEOUS SURFACES

Adsorption in porous sorbents is described by a lattice-gas model cons idering lateral interactions between adsorbed molecules and using a qu asichemical approximation. Chemical and structural imperfections of po re walls are taken into account. Surface composition and the occurrenc e of different adsorption centers are included by introducing certain distribution functions. Homogeneous, stepped, and rough walls of pores are considered. The self-consistent description of equilibrium (the l ocal occupations of the different adsorption centers, isotherms, and i sosteric heats of adsorption) and kinetic characteristics (the diffusi on coefficients of the adsorbed molecules) can be performed with the p resent model. Isotherms as well as a dependence of the isosteric heat of adsorption and the diffusion coefficient on concentration are inves tigated, and a relation between these generated theoretical curves and the corresponding experimental data is briefly discussed. In addition , qualitative description of SF6 isotherms on controlled-pore glasses is presented.