Jim Kubicki
As the world population continues to grow and the space afforded to each human being continues to shrink, water quality will be one of the most significant issues we face. Generally, we think of water pollution as originating from industrial byproducts or accidents such as chemical spills, however, nature plays a major role in water pollution. Water carries and transmits many bacteria, and how those bacteria move through water sources is just one of the research foci of Jim Kubicki, Assistant Professor of Geosciences.
Using the now mature fields of Molecular Dynamics (MD) and Quantum Mechanical (QM) computer simulations along with various spectroscopic techniques, water quality is one of the geochemical systems studied by Kubicki. Kubicki and his colleagues use MD, QM, Atomic Force Microscopy (AFM) and Infrared (IR) spectroscopy to study the interactions of the cell-surface biopolymers of E. coli, natural organic matter, and mineral surfaces typical of those found in aquifers. By modeling the polymer conformations at the surface of bacteria and natural organic matter found on mineral surfaces, Kubicki is working to explain the attachment and release mechanism of bacteria with mineral particles in water supplies.
Another area of research with which Kubicki has dealt with is the modeling of soot, a product of combustion, and the manner in which soot interacts with other environmental pollutants. Others have demonstrated that soot will sequester polycyclic aromatic hydrocarbon (PAH) molecules. By modeling the complexation of pyrene with soot derived from n-hexane (see image below), Kubicki has suggested how PAH molecules may associate with soot via van der Waal's forces, similar to that of soot-soot bonding. As the PAH molecules become tied up in soot, the ability of PAH to biodegrade diminishes.
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Returning to research topics from his Ph.D. thesis, Kubicki recently completed some modeling of glass systems in collaboration with faculty from the Materials Science and Engineering Department. The purpose of this collaboration centered on the investigation of dissolution rates of three glasses of varying Al/Si ratios in an effort to better understand the weathering of plagioclase, the most common mineral in the Earth's crust. Kubicki's ab initio calculations for the structural units of the three glasses showed that as the Al/Si ratio increased, some Si-O bonds increased in length providing an energetically favorable situation for hydrolysis, and therefore dissolution.
Kubicki received his Ph.D. in Geochemistry from Yale in 1989 after which he held postdoctoral positions with the Geophysical Laboratory at The Carnegie Institution of Washington (Washington, DC), Caltech, and the Remediation Research Laboratory in San Diego, CA. In 1998, Kubicki arrived at Penn State in the Geosciences Department. To learn more about Kubicki's research, please visit his web site at http://www.geosc.psu.edu/People/Faculty/FacultyPages/Kubicki/index.html.
