An engineering model for adsorption of gases onto various media

We present an engineering model to describe physical adsorption of pure gases and binary mixtures from sub- to supercritical conditions on flat walls, slits and pores using a single temperature-independent parameter for fluid-solid interactions. The fluid-solid potential is superimposed on the Peng-Robinson equation of state, and the configurational energy integral in the inhomogeneous fluid phase is simplified with a local density approximation. This model is capable of quantitative fits over wide pressure and temperature ranges. Model predictions for physical adsorption of pure gases on flat walls are compared with experimental surface excess, amount adsorbed and composition data.