Monte Carlo lattice dynamics studies of binary adsorption in silicalite

A highly flexible and efficient Monte Carlo lattice dynamics (MCLD) code ha s been developed which takes as input data characterising the microdynamics of the adsorbate molecule within the zeolite framework. Molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations are used to determ ine a physically realistic distribution of adsorption sites within the zeol ite and their relative energies of interaction with the adsorbate of intere st, these sites are then identified with the lattice sites used in the MCLD simulation. In this paper the method is applied to ethane and ethene adsor bed in silicalite. Variable temperature NMR relaxometry experiments are per formed to provide and constrain the input data for the MCLD simulations. Ex cellent agreement between simulated and measured single- and binary-compone nt adsorption isotherms is obtained and the results are interpreted in term s of the relative rate of site desorption of the two species within the zeo lite framework. (C) 1999 Elsevier Science S.A. All rights reserved.