Adsorption and the structure of a hard sphere fluid in disordered quenched microporous matrices of permeable species

Abstract

We have studied the structure and adsorption of a hard sphere fluid in a rigidly fixed array of permeable matrix species. The surface of each matrix particle is represented by a barrier of finite height and width, such that the entire model describes partitioning of a fluid in a set of permeable membranes. We have applied the grand canonical Monte Carlo (GCMC) simulations and replica Ornstein—Zernike (ROZ) equations for partly quenched systems complemented by the Percus—Yevick (PY) closure as our theoretical tools. The pair distribution functions of species and the adsorption isotherms are discussed dependent on the parameters of the model. It is shown that the theory provides adequate description of the behaviour of fluid species in the interior of the matrix particles, inside the barriers, and close to the interface. On the other hand, the coordination numbers for a fluid in the matrix interior and the adsorption isotherms from the ROZ-PY theory are in excellent agreement with computer simulation data.