Adsorption of laterally interacting gas mixtures on homogeneous surfaces

SANCHEZ VARRETTI F. O.; PASINETTI M.; BULNES F. M.; RAMIREZ-PASTOR A. J.

ADSORPTION-JOURNAL OF THE INTERNATIONAL ADSORPTION SOCIETY

SPRINGER

Año: 2017

0929-5607

The adsorption of binary mixtures containing particles A and B on homogeneous substrates is studied by Monte Carlo (MC) simulations, quasi-chemical approximation (QCA), and exact counting of states on finite cells (we call this approach cluster approximation, CA). The energies involved in the adsorption model are five: (1) EA, interaction energy between an A particle and a lattice site; (2) EB, interaction energy between a B particle and a lattice site;(3) wAA, nearest-neighbor interaction energy between two A particles; (4) wAB (=wBA), nearest-neighbor interaction energy between an A particle and a B particle and (5) wBB , nearest-neighbor interaction energy between two B particles. The process is monitored by following the coverage of both species with the simultaneous increasing of the individual chemical potentials of each mixture component. A non-trivial interdependence between the partial adsorptionisotherms was observed and discussed in the context of the lattice-gas theory. The theoretical formalism is used to model experimental data of methane-carbon dioxide mixtures adsorbed on activated carbon. In addition, an excellentagreement was obtained between theoretical and MC simulation results. This finding evidences the usefulness of CA and QCA as a starting point to predict the behavior of a system governed by a large number of parameters.