512 - Evaluating the stability of nano-sized hematite in the presence of dicarboxylic acids
John J. Lenhart1, email@example.com, Steven E. Mylon2, Rachel Heyler2, Eric M. Walton2, Yu Sik Hwang3. (1) Department of Civil and Environmental Engineering and Geodetic Science, The Ohio State University, Columbus, Ohio 43210, United States, (2) Department of Chemistry, Lafayette College, Easton, PA 18042, United States, (3) Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, United States
Low molecular weight organic acids are a ubiquitous component of aquatic systems. This important pool of reactive ligands binds to mineral surfaces and thus significantly influences their physicochemical behavior. Predicting the impact of the adsorbed organic acids on the properties of the underlying mineral hinges upon integrating molecular-level understanding of the controlling surface complexation mechanisms with macro-scale observations of mineral behavior. We are examining the aggregation kinetics of nano-sized hematite in the presence of a suite of dicarboxylic acids of similar size and structure. Results indicate the structure of the adsorbed acid as determined from attenuated total reflectance Fourier-transform infrared spectroscopy, not the mode of adsorption, defines the resulting effect. For example, maleic acid, which directs both carboxyl groups to the surface when it binds enhances stability as defined by the critical coagulation concentration, whereas fumaric acid which binds with just one group appears to only marginally influence particle stability.
Thursday, March 25, 2010 09:25 AM
Influence of Natural Organic Matter on the Fate and Transport of Metals, Colloids and Nanoparticles in the Aquatic Systems (08:30 AM - 11:50 AM)
Location: Parc 55
Room: Cyril Magnin III