Sergey Vasenkov - Chemical Engineering at the University of Florida

UF Chemical Engineering > People > Faculty > Sergey Vasenkov

	Sergey Vasenkov Ph.D., 1994, Novosibirsk University,Russia
	Associate Professor
	Ph : 352-392-0315 svasenkov@che.ufl.edu

	Areas
	Transport in Porous Materials with Hierarchy of Pore sizes,
	Dynamics in room temperature ionic liquids,
	Single-file diffusion in nanochannels,
	Separations of greenhouse gases

Molecular diffusion is one of the most basic, and at the same time most fascinating physical phenomena. It plays a large role in applications related to separations and alternative energy production. The main focus of our research is on the following two directions: (i) understanding diffusion and its relation to structure and functionality in complex nanostructured materials on all relevant length scales, including nanoscale, and (ii) developing optimization pathways for transport in these materials. In our research we use unique experimental technique: pulsed field gradient nuclear magnetic resonance (PFG NMR) at high field (17.6 T) and high gradients (up to 30 T/m). This approach allows monitoring molecular diffusion on the nanometer and micrometer length scales. It has been recently introduced by our group here in Gainesville in collaboration with the National Magnet Lab. Combined application of this technique and computer simulations creates new links between the nanosciences and chemical engineering by allowing direct studies of the relationships between structure and translational dynamics in complex systems. A brief description of main research directions of our group is given below.

Towards Transport-Optimized Nanostructured Porous Membranes and Related Materials

Porous membranes fabricated for separations of gas mixtures are usually structurally heterogeneous. In particular, mixed

matrix membranes contain interconnected networks of pores of different sizes, i.e. networks of micropores with pore sizes approaching the sizes of gas molecules and networks of much larger mesopores. Such membranes have great potential for effective separations of small gas molecules such as CO₂, CH₄, and N₂ from methane-rich biogas produced from biomass processing and flue gas produced by coal-fired power plants. Our research focuses on (i) quantifying different types of gas transport on micrometer and submicrometer length scales in such membranes and related materials, and (ii) establishing a quantitative relationship between these types of transport and macroscopic long-range diffusion and related gas fluxes. This research direction is supported by an NSF CAREER award, CBET.

Transport of CO₂ and Other Gases in Confined Room Temperature Ionic Liquids

Molten salts, which are liquid without any water at temperatures around room temperature, are referred to as room temperature ionic liquids (RTILs). Many RTILs show good solubility for CO₂ and some other small gases. Confinement of RTILs in mesoporous channels of porous solids is a promising strategy for the development of a very attractive type of media for gas separations. Our research will uncover fundamentals of the relationship between transport and structural properties of confined RTILs on small length scales. It is supported by a collaborative research award from NSF, CBET (collaborators are Prof. E. J. Maginn, and Prof. J. K Shah, University of Notre Dame)

Single-File Diffusion for Alternative Energy and Separations

The phenomenon of single-file diffusion (SFD) occurs when molecules cannot pass one another in narrow channels. This results in a highly correlated, anomalous type of transport. SFD is of great potential interest for applications in separations and catalysis. This research direction focuses on the first-time experimental observation of single-file diffusion in gas mixtures and on obtaining fundamental knowledge of this type of transport on various length scales of molecular displacements. Studies are performed in collaboration with the group of Prof. C. R. Bowers, University of Florida. This work is supported by a research grant from NSF, Chemistry.

Recent Publications

1.	Hazelbaker, E.D.; Budhathoki, S.; Katihar, A.; Shah, J.K.; Maginn, E.J.; Vasenkov, S. “Combined Application of High Field Diffusion NMR and Molecular Dynamics Simulations to Study Dynamics in a Mixture of Carbon Dioxide and an Imidazolium-Based Ionic Liquid,” J. Phys. Chem. B 116, 2012, 9141–9151.
2.	Dvoyashkin, M.; Zang, J.; Yucelen, G.I.; Katihar, A.; Nair, S.; Sholl, D.S.; Bowers, C.R.; Vasenkov, S. “Diffusion of Tetrafluoromethane in Single-Walled Aluminosilicate Nanotubes: Pulsed Field Gradient NMR and Molecular Dynamics Simulations,” J. Phys. Chem. C 2012, in press (DOI: 10.1021/jp3054247)
3	Mueller, R.; Kanungo, R.; Kiyono-Shimobe, M.; Koros, W.J.; Vasenkov, S. “Diffusion of Methane and Carbon Dioxide in Carbon Molecular Sieve Membranes by Multinuclear Pulsed Field Gradient NMR,” Langmuir 28, 2012, 10296-10303.
4.	Mueller, R.; Kanungo, R.; Menjoge, A.; Kiyono-Shimobe, M.; Koros, W.J.; Bradley, S.A.; Galloway, D.B.; Low, J.J.; Prabhakar, S.; Vasenkov, S. “Sorbate Transport in Carbon Molecular Sieve Membranes and FAU/EMT Intergrowth by Diffusion NMR,” Materials 5, 2012, 302-316.
5.	Saengsawang, O.; Nanok, T.; Vasenkov, S.; Fritzsche, S. “Relationship between Sorbate Transport Inside and at the Margins of Zeolite Crystals,” Soft Materials 10, 2011, 202-215.