Molecular Simulation Studies of Adsorption and Diffusion of Complex Molecules in Zeolites

Zeolites are very important materials both in the industrial world and to our everyday life. Numerous studies have probed the adsorption mechanisms of zeolites with the goal of designing sorbents with higher capacity and selectivity, and computer simulations have traditionally been applied to gain molecular-level insights for these adsorption systems. However, most simulation studies are limited to small guest molecules without strongly directional interactions, such as short alkanes or CO₂,  while more complex molecules are challenging because of a lack of transferable force fields and efficient algorithms. We present here the development of the TraPPE-zeo force field, that enables the accurate modeling of the adsorption of any type of molecule in all-silica zeolites, and the use of various configurational-bias Monte Carlo moves for enhanced sampling.  These methodological advances allow one to tackle problems of practical interest, such as the adsorption of alcohols, polyols, and furfurals from aqueous solution and of long-chain alkanes from liquid mixtures.