Chemistry & Biochemistry Seminar: "Imaging Nanoporous Particles for Chemical Separations"

Presenter: Dr. Max Lei Geng - University of Iowa

Abstract

Chromatography separations involve chemical and physical processes that cover a wide range of time scales, from molecular diffusion and adsorption at microsecond time scale, to the gradual structural, chemical and physical changes in the chromatography materials at a time scale of hours. These changes result in a degradation in separation capacity, selectivity and throughput over time, but the molecular origins of these changes are not understood.

We have developed multiscale imaging methods, from microsecond time resolution up to hours, to visualize chromatography separation and to investigate these fundamental processes. Molecular diffusion and adsorption are studied through imaging fluorescence correlation spectroscopy to generate images of diffusion rates and adsorption kinetics inside the stationary phase particles. To investigate the fundamental origins for the changes in the particles over time after hundreds of separations have been performed by the column, we imaged the free energy of interactions over equivalent of 1,000 injections through the packing. These imaging methods provide direct information on the fundamental molecular processes central to chromatography separations.

Free