Porous materials, such as activated carbons, zedites, silicas and metal oxides, are widely used in industry for purification, separation and chemical reaction processes. The choice and design of these materials is empirical of present, and the materials are not optimal. Classical methods for interpreting gas behavior in porous solids rely on equations derived in the late 19th and early 20th centuries, and are inaccurate for small pores. The aim of this projects is to provide more powerful methods based in molecular theory, for predicting adsorbed fluid behavior. Modern statistical mechanical methods -- nonlocal density functional theory, percolation theory, kinetic theory and molecular simulation -- will be used to make a systematic study of the role of pore characteristics (size, shape, interconnectedness, etc.) temperature, and intermolecular forces (fluid-fluid and solid- fluid) on the adsorption isotherm, heat of adsorption, solvation force, diffusion and selectivity for fluids and fluid mixtures in model porous materials. Initially, Lennard- Jones fluids will be studied in model materials with (a) independent pores of simple cylindrical or slit geometry, and (b) nonuniform and networked pores, in which pore blocking can occur. The range of independent variables, and the key features that yield each of the observed classes and subclasses of isotherm, will be determined, and the results will be arranged in a form that is easy to use by experimentalists interested in characterizing porous materials. The theory will be developed as a new means for determining pore-size distributions.
