Potential Research Projects for REU Participants
Research projects are available in the following areas:
·
A Novel Approach to
Design of Clean, Efficient Diffusion Flames
·
Carbon Nanotubes for
Environmental Applications
·
Nanostructured
Thin Films for Hydrogen Production by Photosplitting Water
·
Transition to
Hydrogen Economy: Judicious Use of Fossil Fuels
·
A SXC System for
Capture of Fine Particles and Inactivation of Bioagents
·
Nanoparticle Separation and
Filtration
·
Comparison of Cathodic
Electrode Materials in Microbial Fuel Cells to Boost Electrical Power
·
Novel Processes for
Wastewater Treatment
·
Fluorescent In-Situ
Hybridization (FISH) in Anaerobic Digesters for Animal Waste
·
Remediation of Lead
Contaminated Soils
·
Metal Adsorption to
Nanoparticles
· Effects of Nutrients on Bioremediation of Crude Oil
· Remediation of Crude Oil Spills by Chemical Dispersion
A Novel Approach to Design of Clean, Efficient Diffusion Flames
(Richard Axelbaum)
Most
practical combustion processes involve non-premixed combustion of
hydrocarbons. To ensure that these processes are efficient and to
minimize undesirable emissions, combustion should be complete and the flame
temperature should be low so that NOx emissions are low. Soot
production, which can adversely affect efficiency, emissions, and equipment
lifetime, must be controlled, and flame extinction must be avoided. Many
methods have been considered to reduce soot, but these tend to weaken the flame,
leading to extinction and reducing combustion efficiency. In this
research a novel approach, called flame design, is used to design flames that
best optimize efficiency and minimize pollutants, specifically soot and NOx.
Flame design attempts to affect the basic structure of the flame by varying the
temperature-concentration relationship such that the peak temperature of the
flame is coincident with the location of peak radical production and the
oxidizing species extend deep into the fuel side of the flame to minimize the
potential for formation of soot particles. Recent studies have shown that
it is possible to produce a flame that is both strong and soot-free, using a
method involving exchange of nitrogen from the oxidizer stream to the fuel
stream. This approach, which is of significant fundamental interest, is
also of practical importance, but a lack of sufficient fundamental
understanding limits our ability to fully exploit this promising
technology. For example, it is not known whether the effect of nitrogen-exchange
is due to a change in the direction of convection across the flame or to a
change in the detailed structure of the flame. These issues are being
resolved by studying the flames under controlled conditions, where the
direction of convection at the flame front can be reversed at constant
stoichiometric mixture fraction.
REU Project: Effects
of Nitrogen Exchange on Soot Inception and Flame Extinction Under Turbulent
Conditions
An
undergraduate researcher will perform experiments studying the effects of
nitrogen exchange on soot inception and flame extinction. Experiments
will involve gaseous hydrocarbons burning in a turbulent jet diffusion
flame. Soot inception and flame extinction limits will be obtained as
functions of stoichiometric mixture fraction and flame temperature. The
experimental investigation will be supported by extensive analytical and
computational modeling. This project will involve interaction with
researchers at the NASA Glenn Research Center.
The student will perform experiments with a DMA and a furnace reactor to studying the effects of size and composition of the catalyst particles on growth and morphology of carbon nanotubes. Experiments will involve controlling flows and temperatures as well as monitoring and controlling particle size with the DMA. Some scanning electron microscope work may also be warranted.
Nanostructured Thin Films for Hydrogen Production by Photosplitting
Water (Pratim Biswas)
The holy grail of the energy scenario is to move to a hydrogen based economy - relying ideally on solar light, water and photocatalysts for production of hydrogen. There are many challenges that need to be overcome, one of the foremost being the production of hydrogen using completely renewable means.
REU Project: The project will focus on the synthesis and characterization of nanostructured films of widegap semiconductors by gas phase processes. The REU student will work on construction of a photocell for splitting water to produce hydrogen. Hands on experience in use of novel aerosol instrumentation, gas phase reactors for nanoparticle synthesis and a variety of characterization instruments will be obtained.
Transition to Hydrogen Economy: Judicious Use of Fossil Fuels (Pratim
Biswas and Richard Axelbaum)
As the transition to new energy carriers and sources is expected to occur over a period of at least 30 years, it is critical that we ensure that current methods are as less taxing to the environment as possible. Control of problematic pollutants such as oxides of nitrogen, fine particles, mercury and carbon dioxide need to be addressed.
REU Project: The student will work on new designs of coal combustion systems - in oxygen-carbon dioxide combustion environments wherein CO2 control is more feasible. The student will evaluate the fine particle formation characteristics in such modified systems, and the impact of nanostructured sorbents for mercury control. Hands on experience in use of novel aerosol instrumentation, gas phase reactors for nanoparticle syntheis and a variety of characterization instruments will be obtained.
A SXC System for Capture of Fine Particles and Inactivation of
Bioagents (Pratim Biswas)
Novel SXC (soft xray enhanced corona) systems have been developed in AAQRL for control of fine particles. Work in our Lab has also demonstrated that bioagents can be inactivated very effectively in such systems. The SXC system has application in many different areas related to indoor air quality (residential homes, aircraft cabins, homeland security, etc).
REU Project: The student will work on testing the capture efficiency of the SXC device for a range of particles - both inorganic and biological. Mechanistic details of charging of nanoparticles will be determined in these systems. Studies to aerosolize, measure and inactivate bioaerosols will also be conducted. Hands on experience in use of novel aerosol instrumentation and a variety of characterization instruments will be obtained.
Nanoparticle
Separation and Filtration (Da-Ren Chen)
Particulate filtration using filtration media plays an important role in industrial hygiene for the protection of workers in working places. With the increase of the usage of advanced technologies, especially for Nanotechnology, workers are often exposed to environments in which ultrafine particles will be generated in the processes of manufacture, material synthesis and material property improvement. For example, thin film coating processes for having better material thermal resistance, reducing the material corrosion or increasing the material surface hardness usually involve the evaporation and condensation of special metals or alloys. Particles produced from these processes are normally in the nanometer size range. In order to protect workers in these working places, removal of these nanometer particles by filtration becomes an important issue. Meanwhile, recent evidence shows that nanometer particles could cause more damage to human body. It is well known that inhaled particles in submicron size range can easily penetrate through extrathoracic and tracheobronchial regions of human lung and deposit on the lung wall in the alveolar region (due to very low air velocity, long residence of particles and small alveolar sacs). For particles depositing in the alveolar region, the clearance process takes place by the scavenging and engulfment of particles by free alveolar macrophage cells. Once engulfed by free alveolar macrophages, they will be carried towards the mucocillary escalator by chemotaxis, on to the gastrointestinal tract, and eventually be removed from human lung. However, particles in the sizes of nanometer may be deposited in places where they cannot be removed by macrophage cells. The deposited particles may be accumulated there or redistributed to other parts of human body through human circulation systems. Further evidence also shows that macrophage cells are totally immobilized when exposed to nanoparticles. As a result, possible illness can be induced.
In the filtration process, it is known that particle impaction serves as the major mechanism for large particle removal while the diffusion mechanism dominates the process in small particle size range. During the transition from the impaction mechanism to diffusion one, there will be a maximal point in the penetration curve at a certain particle size. Much work has been done on the subject of maximum penetration from both experimental and theoretical aspects. Further recent experimental works have demonstrated that nanoparticles penetrate filter media due to the thermal rebounce or particle reentrainment. The result is very alarming from the viewpoint of industrial hygiene. Therefore, recent focuses of Nanoparticle Research and Technology Laboratory (supervised by Dr. Chen) on the subject of nanoparticle filtration are (1) to develop nano-aerosol generators for testing the penetration efficiency of filtration media; (2) to design and evaluate apparatuses to classify generated nanoparticles into narrow size distributions and to detect the concentration of classified nanoparticles; (3) to develop standard experimental setup and procedure to properly evaluate the performance of filter media at nanometer size range.
REU Project: Experimental
Evaluation of the Filtration Performance of Filter Media for Nanoparticles
Comparison of Cathodic Electrode Materials
in Microbial Fuel Cells to Boost Electrical Power (Lars Angenent)
We have developed a novel, continuously-fed microbial fuel cell (MFC) configuration for simultaneous wastewater treatment and electricity generation: the upflow microbial fuel cell (UMFC). We measured a high internal resistance of 84 W in the UMFC, which prevented power outputs beyond 3.25 W/m3, because of a drop in operating potential (He, Minteer, Angenent 2005). In general, the internal resistance is high whenever a low current is registered in a MFC with a large redox potential difference. Typically, a high internal resistance is caused for MFCs by one of two reasons: (i) high ionic resistance of electrolytes, such as the anode and cathode solutions and the proton-exchange membrane (i.e., Ohmic limitations) and (ii) slow reduction rates for the cathode reaction. We reduced the internal resistance of the UMFC from 84 to 41 W by using Platinum (Pt) coated electrodes instead of ferricyanide as the catholyte in the cathode chamber, which increased the power output to 5.07 W/m3. This showed that the slow reduction rate in the cathode was an important limiting factor of the UMFC. To further reduce the internal resistance you will experiment with novel cathodic electrode materials in a microbial fuel cell.
He, Z., S. D. Minteer and Angenent, L. T. (2005). "Electricity generation from artificial wastewater with an upflow microbial fuel cell." Environmental Science & Technology 39(14): 5262-5267.
Novel
Processes for Wastewater Treatment (Muthanna Al-Dahhan)
REU Project #1: Evaluation of Different Configuration of Anaerobic Digesters for Animal/Farm Wastes Treatment.
In this project the performance of different reactor designs in which different reactor geometry, internals and way of mixing gas recirculation, slurry recirculation, mechanical agitation, etc. will be evaluated.
REU Project #2: Treatment of the Anaerobically Digested Animal Wastes by Micro Algae
In this project the resulting nutrients (i.e., nitrogen and phosphorous present effluent) from the anaerobic digestion process will be treated using micro algae where grown algae can be harvested and converted to high value products.
REU Project #3: Wastewater Treatment Via Catalytic Wet Oxidation.
In this project the concentrated waste water are treated catalytically using a newly developed pillared clay catalyst in packed bed reactor. The performance of such catalyst using different oxidants such as air, pure oxygen, hydrogen peroxide will be studied and the needed models will be developed.
Biomass to Hydrogen (Mike Dudukovic)
Project
description to follow.
Corn to Ethanol (Mike Dudukovic)
Project
description to follow.
Remediation of Lead
Contaminated Soils (Daniel Giammar)
Missouri is the
largest lead producing state in the United States. Lead mining and smelting have resulted in the
contamination of soils and sediments.
The mobility of lead in soils and sediments influences lead
bioavailability and has implications for the quality of groundwater and surface
water resources.
REU Project #1:
Phosphate Addition for In Situ
Lead Immobilization
Phosphate can be added to lead-contaminated soils to immobilize the lead in situ through the formation of insoluble lead phosphates. The project will investigate the use of different phosphate sources, including the calcium phosphate in fish bones, for reaction with dissolved lead. Dissolution rates of calcium phosphates and precipitation of lead phosphates will be determined in batch reactors. The precipitated solids will be investigated to determine their chemical structures and long-term stabilities.
REU Project #2: Lead Adsorption to Mineral Surfaces in the Environment
Lead adsorption to naturally occurring minerals, including iron oxides and clay minerals, can affect its mobility in contaminated soils and sediments. Work in this project will investigate the adsorption of lead onto different mineral surfaces at different solution compositions. Equilibrium adsorption will be determined in a series of batch experiments, and evaluation of adsorption rates will be determined in flow-through experiments using packed columns.
Metal
Adsorption to Nanoparticles (Daniel Giammar)
The high surface area to mass ratios of nanoparticles can greatly enhance the adsorption capacities of sorbent materials. In addition to having high specific surface areas, nanoparticles also have unique adsorption properties due to different distributions of reactive surface sites and disordered surface regions. The effect of particle size on the adsorption of dissolved heavy metals to iron oxide and titanium dioxide nanoparticles will be studied in laboratory-scale experiments. Iron oxide and titanium dioxide are good sorbents for metal contaminants. The project will involve conducting bench-scale experiments, using instruments for trace element analysis, and modeling adsorption equilibrium.
Effects of Nutrients on Bioremediation of
Crude Oil (Brian Wrenn)
Biodegradation of oil on contaminated shorelines is often limited by nutrients, especially nitrogen and phosphorus. As such, shoreline oil-spill bioremediation can be effected by providing sufficient quantities of nutrients to the shoreline. Because shorelines are open environments, where washout due to the action of waves and tides can occur, several fertilizer formulations (e.g., slow-release, oleophilic) have been developed as long-term nutrient sources. Stimulation of oil biodegradation by fertilization depends on the competition between microbial uptake and washout of nutrients from the contaminated sediments, but most research on the effects of nutrients on oil biodegradation has been performed in closed systems where the kinetic and stoichiometric effects of nutrients are difficult to distinguish. Nutrient washout from intertidal zones can be simulated in continuous-flow beach microcosms in which oil is retained by adsorption to sand particles but nutrients are removed by water flow. Experiments with these microcosms have shown that, whereas nutrient availability limits the rate of oil biodegradation early in the bioremediation process, another factor (e.g., intrinsic biodegradability or bioavailability of residual hydrocarbons) becomes limiting after a short period (2-3 weeks) of biological weathering. The goal of this research is to develop mechanistic models, based on the principals of reactive transport of nutrients, to guide spill responders in choosing efficient and effective procedures for applying nutrients and other bioremediation amendments during shoreline cleanup operations. In addition, the characteristics that should be considered in the design and selection of slow-release or oleophilic fertilizers will be determined.
REU Project #1: Measurement of Nutrient Uptake Kinetics During Crude Oil Biodegradation
An undergraduate researcher will use continuous-flow beach microcosm reactors to investigate the relationships between the rates of microbial growth, nutrient uptake, and oil mineralization as the composition of the oil changes due to biodegradation. The rates of these processes will be correlated with oil composition to identify characteristics that cause the system to switch from nutrient limitation to limitation by biodegradability or bioavailability.
REU Project #2: Effects of Slow-Release and Oleophilic Fertilizers on Oil Biodegradation
The rates of nutrient release from commercial slow-release or oleophilic fertilizers will be measured in sterile continuous-flow beach microcosms. A reactor model incorporating nutrient release, microbial uptake, and washout will be developed to predict oil mineralization rate. The model predictions will be tested in biologically active microcosms.
Remediation of Crude Oil Spills by Chemical
Dispersion (Brian Wrenn)
The primary response for crude oil spills to coastal and surface freshwater in U.S. is based on mechanical containment and recovery (i.e., booming and skimming), which is labor intensive, slow, and recovers a relatively low percentage (<30%) of the spilled oil. Chemical dispersion, which promotes entrainment of the oil into the water column as small droplets by addition of surfactants to the floating oil, may provide an effective response alternative in some cases. Unfortunately, many uncertainties remain regarding the effectiveness of chemical dispersion and the ecological effects of the dispersed oil, making it difficult for spill responders to evaluate the relative benefits and potential impacts of various response alternatives. For example, because chemical dispersion removes oil from the water surface but not from the environment, it may protect water surface and shoreline resources at the expense of water column and benthic ecosystems. Since the ultimate fate of chemically dispersed oil depends on its biodegradability, this research will investigate factors that control the rate and extent of microbial biodegradation of dispersed crude oil.
REU Project: Biodegradation Kinetics of Chemically Dispersed Crude Oil
The relationship between the biodegradation rate of crude oil, as measured by the rates of carbon dioxide production and depletion of specific oil components (e.g., normal alkanes), and the oil-water interfacial area of dispersed oil suspension will be investigated. Suspensions of dispersed crude oil with different oil-water interfacial areas will be prepared by varying the dispersant-oil ratio or the chemical characteristics of the dispersant. Effects of surfactants on attachment of hydrocarbon-degrading bacteria to the dispersed oil droplets will be investigated by microscopic examination of the dispersed oil.