Application of integrated computational chemistry system to the design of inorganic membranes

Today inorganic membranes attract a lot of interest as a growing field. Mai n focus of those activities is on the development of membrane materials, wh ich can offer high permselectivities with acceptable high permeances. The n eed for high permselectivity beyond those limited by Knudsen flow requires the estimation of the factors, which determine the permselectivity. Plausib le theoretical models based on physical or chemical reasoning is desirable to guide systematic development efforts for designing next generation inorg anic membranes. Here we reviewed our attempts to generate theoretical model s based on the molecular dynamics method for this purpose. As a first attem pt, simulation was performed at specific conditions where the Knudsen theor y can be applied and can be reproduced well by our simulation methodology. Molecular dynamics simulation at 373 K of the permeation of iso- and n-buta nes through ZSM-5 type silicalite membrane are presented. After 200 ps of s imulation time the permeation of n-butane was observed whereas the permeati on of iso-butane was not observed. The calculated permeability of n-butane, which is close to experimental data, is also presented. A study on the aff inity membrane for the separation of CO2 at high temperature is presented a nd the prospect of permselectivity of CO2 is demonstrated. (C) 1999 Elsevie r Science B.V. All rights reserved.