Recent developments in Monte Carlo (MC) simulation techniques have enabled the accurate calculation of sorption isotherms of a variety of molecules in zeolites. Using the example of separation of isomers of hexane we demonstrate the power of MC simulations for screening of zeolite adsorbents for maximum separation selectivity. The simulations underline the exploitation of entropy effects during mixture sorption (c) 2006 Elsevier B.V. All rights reserved.