Student Abstracts: Materials Sciences at INEEL

Experimentation on the Uptake and Release of Sodium Lactate by Silica - based Mesoporous Colloids. DAWN DECHAND (Kansas State University, Topeka, KS 66614) GLENN MOORE (Idaho National Engineering and Environmental Laboratory, Idaho Falls, ID 83415) .
In sites contaminated with trichloroethylene (TCE), native microbial cultures can degrade TCE if provided with the proper nutrients, such as lactate. The research focuses on developing silica-based colloids and characterizing their ability to transport and release lactate through the subsurface. Specifically, this paper discusses the analysis of colloids synthesized with F127 surfactant and tetra methyl ortho-silicate (TMOS) and the quantification of their uptake and release of lactate. This synthesis produces hexagonally templated, mesoporous colloids with mobility and zeta potential less than that of soil colloids. Due to the mutual negative charges associated with both lactate and silicon oxide tetrahedrals, forcing the colloids to uptake lactate required experimentation with multiple physical methods and chemical environments. It was found that mixing the colloids with lactate together, then immersing in hexane, and finally oven-drying at 100°C while using methanol as a rinse and transfer agent was the best method of preparation; these colloids slowly released lactate for more than one week. However, further studies are being completed to better quantify this release, perfect the method of colloid synthesis, model the transport of these particles through the subsurface, and analyze the ability of microbes to consume the lactate contained in the colloids.