An Extended Langmuir Model for Adsorption of Gas Mixtures on Heterogeneous Surfaces

A model is presented for calculating the adsorption from gas mixtures on energetically heterogeneous adsorbents. It assumes a uniform distribution of adsorption energies and the applicability of the extended Langmuir model for adsorption from gas mixtures on each patch of surface of uniform energy. The model can be used directly to calculate mixed gas adsorption with only pure gas data at, at least, two temperatures. However, a special case of the model is derived which allows for an analytical solution and which requires pure gas data only at one temperature. The analytical form of the model is tested against considerable mixed gas adsorption data with satisfactory results. The model also compares well with other models. Moreover, it is explicit with respect to the component amount adsorbed from a gas mixture, is noniterative, and provides savings in computation.