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Figure 1: 2 x 2 x 2 unit cells of zeolite Rho structure. |
Molecular sieving by microporous materials - such as zeolite Rho, shown in Figure 1 - is a method of separation with many industrial applications, such as in air and hydrocarbon separation, as well as in catalytic processing. When based on equilibrium conditions, molecular sieving relies on the exclusion of large molecule species due to differences between pore diameter and molecular size. However, when this difference is sufficiently small, kinetic molecular sieving, based on differences between diffusivities of the various components, becomes attractive. Understanding the behaviour of adsorbates in microporous materials is essential to the analysis and development of processes involving kinetic molecular sieving.
Professor Suresh Bhatia of the Department of Chemical Engineering at the University of Queensland is leading a research group studying the transport and adsorption of molecules in nanomaterials, in order to develop a new understanding of how these materials may be used in separation and catalysis technologies. Their research focuses on the characterization of these nanomaterials, as well as the equilibrium and transport properties of fluids confined in their nanostructure.
The pores of these nanomaterials can range in diameter from 5 to 50 ångströms, and since the molecules of interest are typically 3-5 ångströms in size, transport in the pores is heavily dependent on pore size. The group uses home-grown Fortran code to run Monte Carlo and molecular dynamics (MD) simulations to solve the equilibrium states and model the transport of molecules through the pores. These simulations are very memory intensive, as they can involve solving the differential equations of motion for several hundred to over a thousand molecules. A typical simulation, running on QCIF-funded supercomputers at UQ's HPC facility, can take up to 2 weeks to complete.
The Bhatia group is one of the largest users of the UQ HPC supercomputers.
Contacts
Professor Suresh Bhatia and colleagues
Department of Chemical Engineering,
University of Queensland
Publications
A.V. Anil Kumar and S.K. Bhatia. 'Quantum Effect induced Reverse Kinetic Molecular Sieving in Microporous Materials'. Phys. Rev. Lett., 95, 245901 (2005).
Bhatia, S.K., O. Jepps and D. Nicholson, 'Tractable Molecular Theory of Transport of Lennard Jones Fluids in Nanopores', J. Chem. Phys., 120, 4472-4458 (2004).
Jepps, O., S.K. Bhatia and D. Searls, 'Wall Mediated Transport in Confined Spaces: Exact Theory for Lennard Jones Fluids', Phys. Rev. Lett., 91, 0126102 (2003).
Written by T. Curtis, August 2006.