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Carmen L. Huffman
Assistant Professor, Physical Chemistry

Research Interests:

Our research focuses on the analysis of molecular interactions and distribution in complex systems containing a solid/liquid interface. Our solid of choice is silica in the form of silica gel.

One project involves the examination of the distribution of solute molecules in a solution containing both surfactant molecules and a silica gel surface. The surfactant that we're currently using, cetylpyridinium chloride, readily adsorbs to the silica surface but can also form micelles in solution. When these micelles adhere to the surface, they're referred to as admicelles. Naturally, both micelles and admicelles can solubilize nonpolar solutes that would ordinarily be insoluble in water. Adsolubilization is when such a solute resides in an admicelle, and this phenomenon is particularly interesting because of its impact in drug delivery. We're interested in understanding what drives/influences the distribution of nonpolar solute molecules between the aqueous solution, free micelles, admicelles and the silica surface. In particular, we're studying the effects of ionic strength on this distribution. Both the solute and the surfactant are UV-active, so solute and surfactant concentrations can easily be monitored with UV/vis spectroscopy.

Another project of our group is the investigation of the use of silica gel as both a remediation and analysis tool for water contaminated with heavy metals. Arsenic is a common soil contaminant in nearby Barber Orchard due to the past use of aresenic-laden pesticides and fertilizers. Although arsenic is certainly toxic to humans, different species of arsenic, like inorganic forms, are more dangerous than others. Current methods for distinguishing one species from another (called speciation) include chromatography, which can involve complex method development, and ICP-OES-MS, which is quite expensive. Our goal is to develop a novel method of speciation through the analysis of the binding of various arsenic species to a modified silica surface. Binding will occur at the silica/aqueous interface. Then the silica will be dried and analyzed using thermogravimetric and differential thermal analyses. We hope to identify unique binding signatures for different species that can then be used as a library for speciation. The method will be a simple and inexpensive alternative to those currently in use.


  
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