Past Research Accomplishments Characterized the structure and dynamics of H2O and ions at the water/mineral interface of quartz, muscovite, and hectorite using variable temperature solid-state NMR Examined local As structure in oxyanions and at mineral surfaces using 75As NMR, including development of a new ultra-wideline method Applied advanced solid-state NMR techniques to characterize Sr structure and binding in inorganic salts, natural and synthetic clays, homogeneous nucleation products, and titanate sorbants using 87Sr NMR Examined homogeneous nucleation products of colloidal silica reacted with simulated high-level nuclear tank waste leachate using solid-state NMR Formulated, developed, and characterized the structural, thermal, and thermo-mechanical properties of inorganic/organic composite wet friction materials using TGA, TMA, DSC, SEM/EDS, FTIR, GC/MS, Instron tensile analysis, and mechanical dynamometers A brief description of my most recent/current research projects are listed below: Aggregation of Natural Organic Matter Natural organic matter (NOM) and the humic components of NOM (humic acids, fulvic acids, and humus) are the most abundant sources of carbon on Earth and exhibit extraordinary chemical versatility; thus, NOM plays a number of important roles in soil, aquatic, atmospheric, industrial, and even medicinal chemistry. Scientists are beginning to view NOM as aggregates of smaller organic molecules rather than macromolecular polyacids. I would like to determine how alkaline earth cations influence the aggregation of NOM using combined NMR and molecular modeling. Ion-Surface interactions at the mineral/water interface Many environmentally important chemical process take place at the water/mineral interface, such as dissolution, ion sorption, and carbonate nucleation. The influence that pH, temperature, and ionic species exert on the interfacial structure and dynamics are fundamental to our understanding of these processes, and I examine the effects of these properties using solid-state NMR. Research Plans: Once on a tenure track, I intend to implement a research program focusing on socially important issues of environmental and materials chemistry from a physical perspective. Undergraduates working with me will have opportunities to explore structure and dynamics related to the degradation of organic and inorganic materials under environmentally relevant conditions, contaminant-mineral interactions, cement chemistry, the chemistry of natural organic matter, and the role of H2O in these materials/processes using nuclear magnetic resonance (NMR) and a variety of other analytical tools. I also have special interests in low-gamma quadrupolar NMR, geochemistry, and interdisciplinary approaches to solving problems. Please contact Dr. Bowers directly if you wish to learn more about upcoming research opportunities.
Pegmatite Intrustion at the Harding Mine near Santa Fe, NM.
Natural Abundance 43Ca NMR of Inorganic Materials Ca2+ is an important ion in environmental, biological, and industrial systems, including the natural and synthetic materials used frequently in the construction industry. In many cases, Ca2+ is present in amorphous or poorly crystalline materials and little experimental data is available regarding the structural and dynamical behavior of this ion on the molecular scale. NMR can be a particularly powerful method for extracting this type of information, but the NMR active isotope 43Ca has a very low abundance (0.1%), leading to severe sensitivity limitations. Enriching the concentration of 43Ca is expensive and not possible when examining natural or existing Ca-bearing inorganic phases. I am trying to improve our ability to acquire 43Ca NMR spectra and use natural abundance 43Ca NMR results to characterize Ca2+ environments in a variety of poorly crystalline materials of environmental, industrial, and biological interest, particularly cements. (image at right courtesy PNNL)http://www.emsl.pnl.gov/shapeimage_12_link_0
Geoffrey M. Bowers Research Page