Molecular Simulation of Pervaporation of a Lennard-Jones Mixture Using a Crystalline Membrane

Numeric simulation of the pervaporation process is carried out using molecular dynamics. Various conditions of the separation of an ideal binary Lennard-Jones mixture using a crystalline membrane are considered. Components of separated mixtures differ in regards to the energy of interaction with molecules of the membrane. As a result of simulation, fields of concentrations and densities along the cell, as well as flux values of components, are obtained. In addition, coefficients of the diffusion of components in the membrane are computed. It is shown that the correspondence of numeric simulation data to macroscopic mass transfer equations are observed in all cases. It can be concluded that the behavior of molecules in a nonequilibrium system with a scale of several dozens of molecule diameters corresponds to transfer equations of linear nonequilibrium thermodynamics. Results of numeric simulation show the selectivity of a membrane in regard to the component with a larger interaction energy. It is shown that molecular simulation is able to predict the main characteristics of membrane separation (fluxes, selectivity, adsorption, and diffusion coefficients).