Synthesis and Characterization of Sugar-Imprinted Titanosilicate Materials Prepared by Surfactant Co-Templating

Tuesday, November 9, 2010: 10:10 AM
Grand Ballroom I (Salt Palace Convention Center)
Suvid Joshi1, Navaladian Subramanian1, Gifty Osei-Prempeh2, Barbara L. Knutson3, Hans-Joachim Lehmler4 and Stephen E. Rankin3, (1)Department of Chemical and Materials engineering, University of Kentucky, Lexington, KY, (2)Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, (3)Chemical and Materials Engineering, University of Kentucky, Lexington, KY, (4)University of Iowa, Iowa City, IA

Templated silica materials synthesized and developed during the past two decades have found a large number of potential applications in the fields of catalysis, sensing, optics and separations. Recently, our group began investigating using mixed surfactant templating for preparation of selective adsorbent materials for saccharide separations. The immediate targets are C5/C6 sugar separations to allow better utilization of the different types of sugars generated during hydrolysis of lignocellulosic biomass. Our approach utilizes interactions between specific surfactant headgroups and precursors to allow the surfactant not only to act as a passive space-filling pore-template, but also to actively direct the formation of complementary sites for separation of target compounds. Silica is a wonderfully versatile matrix for mesoporous materials, but it does not necessarily exhibit strong binding to sugars. Titania is known to provide high affinity for biomolecules, and incorporation of titania in the silica framework to form a hybrid material would be expected to help in obtaining materials better suited for binding and separation of target saccharides. In this work, the synthesis of templated silica and silica/titania hybrid materials will be demonstrated and discussed. Alkyl maltosides and glucosides will initially be used to provide imprinting in the material. The saccharide surfactants are expected to bind strongly and selectively with titanium during synthesis. A cationic surfactant (CTAB) is also added to the mixtures to provide micelle stability and to strengthen interactions with the silica matrix. These materials are characterized using nitrogen adsorption, X-ray diffraction and transmission electron microscopy. Diffuse reflectance uv-vis spectroscopy is used to characterize the coordination state of titania in response to complexation to saccharide surfactants and other process variables. Tetracoordinated, isolated titanium sites are thought to be active sites for epoxidation reactions, but it is unknown what coordination is required for binding of saccharides. Novel, newly synthesized alkyl xyloside surfactants will also be used for some samples to understand how a C5 saccharide headgroup influences the efficacy of pore templating and saccharide imprinting at the pore surface.

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