"Tropospheric Trace Gas
Cycles in East Asia"
Gregory R.
Carmichael
(Professor,
Chemical and
Biochemical Engineering)
A detailed understanding of the
relationships between the emissions and the resulting distribution of primary
and secondary species in the atmosphere is a requisite to designing actions for
the maintenance of a healthly environment.
To better understand the transport and fate of trace gases and
pollutants in the atmosphere, comprehensive atmospheric transport-chemistry
models have been developed. These
models treat transport, chemical transformations, emissions and deposition
processes in an integrated framework, and serve as representations of our
current understanding of the complex atmospheric processes. One of the fastest
economically growing regions of the world is Asia. The potential for pollution problems in this region can be
anticipated based on present and projected growth in the emissions from the
region, and the close geographical proximity of many of the major industrial
and urban centers (e.g., Tokyo, Seoul, Taipei, Shanghai, Hong Kong, etc.). In this project, the long-range transport of
pollutants in Asia is studied using a three-dimensional transport/chemistry
model. An REU student working on this
project will learn that chemical engineering is an excellent discipline for
analyzing the complex transport and chemistry issues at the heart of
environmental analysis. The student
will run atmospheric chemistry models that include potentially important
heterogeneous reactions to simulate different chemical environments including
rural, urban, and remote. This will
lead to an understanding of how partical emissions affect key atmospheric
species. They will also develop an
appreciation for the relationships between anthropogenic activity, air quality
and climate. In addition they will be
introduced to high speed computing and computer visualization.
"Air Pollution Control and Optical Remote Sensing"
William
Eichinger (Associate Professor, Civil and Environmental
Engineering)
A research assistant is desired to participate in a series of field experiments during the summer of 2002 in Montana and Iowa. These experiments will use laser radars and conventional meteorological instruments to measure particulate emissions from forest fires and to estimate evaporation over large areas. These instruments measure the concentration of various atmospheric contaminants in three dimensions. The experiment in Iowa is part of a much larger scale effort to validate satellite estimates of surface properties, so that the student will be exposed to a wide range of measurement types and platforms. The student would be expected to work as part of a team, operating the equipment as well as taking and analyzing the data from them. Previous experience is not expected, a willingness to learn is.
"
Heterogeneous Atmospheric Chemistry of Trace Gases on Oxide Particles and Mineral Dust"
Vicki H.
Grassian (Associate Professor, Chemistry and Chemical and
Biochemical Engineering)
Undergraduate students working in
the Grassian group will have the opportunity to do laboratory studies in the
area of heterogeneous atmospheric chemistry, i.e. reactions involving gases and
aerosols. In the stratosphere, chemical
reactions of chlorine reservoir species that take place on the surface of ice
crystals play a critical role in the formation of the Antarctic ozone
hole. Although it is has become
increasingly clear that particles in the troposphere including ice, dust, soot
and salt particles - play a role in the chemical balance of the troposphere,
there are few studies that quantify these reactions. Undergraduates will
utilize the techniques of infrared spectroscopy and mass spectrometry to
unravel and quantify the chemistry that takes place between trace atmospheric
gases and the surface of oxide particles and mineral dust. The research projects in the Grassian lab
provide undergraduate students with the opportunity to learn about atmospheric
chemistry as well as surface analysis and surface science. Initially, students will work closely with
senior graduate students and postdoctoral associates. During the first few weeks, students are exposed to a wide
variety of new laboratory techniques.
The students eventually become familiar enough with the techniques so
that they can perform their own experiments.
Undergraduate students will also participate in data processing and data
analysis as well as weekly research group meetings and individual
meetings.
"The Fate and Transport of Semi-Volatile Organics in Environmental
Systems"
Keri Hornbuckle (Assistant Professor, Civil and Environmental
Engineering)
Dr. Hornbuckle's research concerns the exchange of semi-volatile organic compounds (SOCs) across atmospheric interfaces. She is interested in the behavior of SOCs at interfaces as it affects fate and transport of these compounds. The rate and overall tendency of a compound to cross atmospheric boundaries influences long-range chemical atmospheric transport, ecosystem and human exposure, and eventual fate of the compound. The compounds Dr. Hornbuckle studies degrade slowly under normal environmental conditions, are widely produced as a result of human activity, and tend to bioaccumulate. These compounds include DDT, its derivatives and other chlorinated pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). These compounds have been distributed globally and have been found in virtually all environmental compartments. Undergraduate researchers have been involved in two of Dr. Hornbuckle's current federally-funded research projects. One student completed a computer-assisted design (MicroStation) of a climate chamber. Another student designed, edited, and published a web page describing the climate chamber project. A third student had responsibilities for the analysis of samples collected during a resuspension plume event in Lake Michigan.
"Spectroscopic
Investigations of NOx Catalysts"
Sarah C. Larsen
(Assistant Professor, Chemistry)
Environmental
catalysis refers to the use of catalysts to solve problems related to
pollution. Cation-exchanged zeolites are effective environmental catalysts for
applications, such as emission abatement and environmentally benign synthesis.
Currently, we are interested in the two applications of environmental catalysis
listed below.
(1) Remediation of nitrogen oxides and volatile organic
compounds (VOC’s)
· EPR studies (experimental and computational) of transition metal-exchanged zeolites, which are active catalysts for the decomposition of nitrogen oxides.
· Solid state NMR studies (15N and 13C) of proposed reaction intermediates for the selective catalytic reduction (SCR) of NOx on CuZSM-5, HZSM-5 and FeZSM-5.
(2) Selective oxidation reactions for environmentally benign synthesis
· Selective hydrocarbon thermal and photooxidation in cation-exchanged zeolites using spectroscopic techniques, such as in situ NMR, in situ FTIR, and UV/Vis and ex situ chromatographic methods for product analysis.
An undergraduate (REU) student working in my group would prepare zeolite samples. After characterization of the zeolite samples by X-ray diffraction and elemental analysis (to determine the extent of exchange), the undergraduate student would screen the zeolite for catalytic activity using gas chromatography. The REU student would then undertake spectroscopic studies of the catalyst samples with the assistance of a graduate student. The estimated timetable for this project involves approximately 4 weeks of catalyst preparation and evaluation and 4 weeks of spectroscopic studies and data analysis.
"Cretaceous
Paleoclimatology"
Greg Ludvigson
(Associate Professor, Geoscience)
The mid-Cretaceous, an interval of geologic time lasting
from about 110 to 90 million years ago, represents what is perhaps the warmest
climatic episode of Earth History that readily lends itself to detailed
environmental reconstruction. This time period has been of special interest to
the community of climate modelers charged with responsibility for developing
reliable computer models to forecast the results of expected future global
greenhouse warming. In order to retune existing climate models for conditions
very different from those of today, modelers are performing calibration
experiments through hindcasting of well-studied past "greenhouse
worlds". The mid-Cretaceous is
also a very important time in the history of life on this planet. The organisms
that dominate our modern terrestrial ecosystems, the flowering plants, birds,
and mammals, underwent explosive growth in genetic diversity in the
mid-Cretaceous hothouse. A team of
geologists from The University of Iowa and the Geological Survey Bureau is
engaged in a project to develop quantitative paleohydrologic and paleoclimatologic
data that will be used for validation of computer climate model simulations of
the Cretaceous interior of North America.
This project is being supported by grants from the U.S. National Science
Foundation, the Petroleum Research Fund of the American Chemical Society, The
University of Iowa Carver Scientific Research Initiative, and The University of
Iowa Center for Global & Regional Environmental Research. Earlier funding
support came from the Iowa Science Foundation and the National Geographic Society. Some related websites:
http://www.igsb.uiowa.edu/inforsch/greenhse/grnhouse.htm
http://www.igsb.uiowa.edu/inforsch/greenhse/grnhouse.htm
"Green Chemistry and Solid-State Synthesis”
Leonard MacGillivray
(Assistant Professor, Department of Chemistry)
Whereas more traditional approaches to chemical synthesis have focused upon atoms and molecules individually, research in my group encompasses understanding principles that govern the effects of intermolecular interactions (e.g. hydrogen bonds) on the structure and properties of assemblies of atoms and molecules in the field of supramolecular chemistry. The structure of DNA and ability of enzymes to catalyze chemical reactions are examples from biochemistry that are regulated by such interactions and we address whether such forces may be used to confront long-standing problems with new perspectives or design new molecules and materials with unique properties. Specifically, my group is currently developing the solvent-free environment of the solid-state as a medium for controlling chemical reactivity. To this end, we are utilizing molecules that function, in a similar way to the structure of DNA, as linear templates that direct reactions in solids by way of hydrogen bonds. We have, for example, demonstrated the ability of 1,3-dihydroxybenzene, and derivatives, to induce alignment of C=C double bonds in the solid-state such that the two reactive sites undergo a photoinduced [2+2] addition reaction, forming two C-C single bonds. This method has, notably, enabled us to conduct molecular synthesis by design, a concept central to the development of liquid phase synthesis (e.g. natural product synthesis). We are currently applying this approach to: 1) traditional problems of synthetic chemistry and 2) a prospect of constructing molecules unavailable in the liquid phase.
"The role of
Green Rust Minerals in the Fate and Remediation of Groundwater"
Michelle Scherer
(Assistant Professor, Civil and Environmental Engineering)
Green rusts are greenish-blue iron minerals containing naturally occurring anions such as chloride, sulfate, or carbonate. The inclusion of anions in the iron mineral matrix create a highly reactive compound, capable of reducing a host of redox-active pollutants The reduction of both PCE and TNT by synthetic green rusts will be explored in controlled, anoxic batch systems. The student will prepare the green rust compound in an anaerobic chamber following an already developed synthesis technique. The synthesis itself can be quite fascinating, as the precipitate goes through a series of dramatic color changes (orange to brown to bright green-blue). When a stable compound has been prepared, individual vials will be spiked with the contaminant and monitored over time. The student will be exposed to a variety of analytical techniques, including gas chromatography (GC), high-performance liquid chromatography (HPLC), and UV-VIS spectrophotometry. The student will observe the disappearance of the contaminant with time and quantify the rate of reaction with available kinetic models. Once the student is comfortable with the protocol, several treatments will be designed to explore the factors controlling the rate of transformation in the presence of green rust.
"A Novel Approach to Environmental Remediation: Development of Outer-Sphere
Ligands for Uranyl Carbonate"
Jason R. Telford
(Assistant Professor,Department of Chemistry)
We are working to develop ligands which bind small inorganic complexes by outer-sphere recognition. These ligands take advantage of unique geometric features in the inorganic complexes (such as uranyl carbonate), incorporating recognition of guest topology, van der Waals interactions, and hydrogen bonding. Using outer-sphere coordination (interaction with the metal's pre-existing ligands rather than bonding directly to the metal) imparts selectivity toward a specific metal-complex, and thus provides a directed approach to environmental remediation. This research represents a novel approach toward the design of small-molecule metal-complexing agents, using the same strategy that Nature has taken with metal-binding proteins.
"Environmental Chemical Processes in the Air and
Water"
Mark Young (Assistant Professor,Department of Chemistry)
Students working with our group will have the opportunity to participate in studies of heterogeneous atmospheric chemistry and environmental photochemistry in surface waters. The atmospheric chemistry studies are directed toward an understanding of heterogeneous reactions involving aerosol dust particles, particularly mineral oxides and soot. The photochemical reactions of water samples containing dissolved and suspended organic matter are also being investigated. We are developing new laboratory techniques to obtain relevant data that can be utilized in detailed computer models of the atmosphere. The research involves a variety of experimental methods and utilizes modern spectroscopic instrumentation. The research projects are directed at an exciting, interesting and relevant area of environmental science and will offer an excellent experience for undergraduates interested in environmental chemistry.