2006 NCSU Summer UGRS NSF Sustainability, Energy, and Engineering REU

The 5^th Annual

NC State University

Undergraduate Summer Research Symposium

NSF Sustainability, Energy, and Engineering

REU - Chemical Engineering

Abstracts are listed in alphabetical order by the last name of the corresponding author.

Student Author(s):	Bolivar, Ana I.
Home Institution:	The City College of New York
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Wood and Paper Science
Research Mentor(s):	Richard A. Venditti/ Wood and Paper Science Joel J. Pawlak/ Wood and Paper Science
Title of Presentation:	Development and Characterization of Novel Starch Microcellular Foam Particles for Paper Coatings and Plastic Applications

There is interest in replacing inorganic fillers in paper, coatings and plastics with organic renewable fillers to improve the economics, performance and environmental aspects of products. Starch Microcellular Foam Particles (SMCFP) is a promising material in this regard. This research was undertaken to develop and characterize SMCFP with high light-scattering properties and water resistance. SMCFP were produced using corn starch; which was solubilized in water. The foam structure was created by using ethanol in a solvent exchange technique. The starch was also reacted with Alkyl Ketene Dimer (AKD) wax at different levels in order to develop water resistance. Two methods were used to incorporate AKD: (1) the AKD was coated onto foam particles after formation, and (2) the AKD was mixed with the starch before particle formation. Hexane extraction was used to purify a portion of each of the samples to determine if unreacted AKD existed. It was determined that a minimum amount of AKD was needed in the coating method to develop high contact angle (hydrophobicity) and decrease the water solubility. Brightness of the particles was significantly higher than that of the uncooked starch, presumably due to the development of a porous structure. This was not significantly affected by the levels of AKD. Elemental analysis of purified and unpurified particles indicated that the AKD content increased with AKD charge level but that the reacted AKD was constant with respect to AKD charge level for the coated particles. It is presumed that this is due to the AKD being able to react with the starch surface and so only a small amount of AKD (less than 0.5% of the starch by weight) is needed to cover the surface. In conclusion, a novel method to develop particles with important properties has been developed and the effect of AKD level on properties determined.

Student Author(s):	Campbell, Candice C. Verruto, Vincent J.
Home Institution:	New Mexico State University North Carolina State University
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Chemistry Chemical and Biomolecular Engineering
Research Mentor(s):	Peter K. Kilpatrick/Chemical and Biomolecular Engineering
Title of Presentation:	Stability of Asphaltene-Stabilized W/O Emulsions as Gauged by Critical Electric Field: The Role of Organic Acids

Stable emulsions are of great importance and are often favorable in the food, pharmaceutical, and specialty chemical industries. In the crude oil and petroleum industry, however, stable water-in-oil emulsions are undesirable and lead to costly shutdowns and cleanups, decreased processability, and poisoning of downstream catalysts. Asphaltenes reside in the heaviest crude oil fraction and are largely credited as the culprits in such W/O emulsions. Their ability to self-assemble into an elastic, solid-like third-phase film at the oil water interface allows for some very sophisticated investigations about the stability of these emulsions. This particular investigation uses the critical electric field (CEF) technique, a benchtop apparatus which bears some resemblance to industrial desalting and electrical demulsification technology, to investigate water in model oil and crude oil emulsion stability. Model oils included HOW asphaltenes in 40:60 heptol doped with 9-anthracene carboxylic acid (ACA), a three-ring fused aromatic molecule functionalized with a –COOH group. Doping asphaltenes with ACA typically enhanced the emulsion stability. However, reproducibility was an issue which perhaps stems from the low solubility and slow dissolution kinetics of ACA in the solvents used. Several emulsions made with different crudes were also tested to further assess the robustness of a soon-to-be-published correlation.

Student Author(s):	Conrad, Zachary Nathan
Home Institution:	North Carolina State University
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Chemical Engineering Research Triangle Institute
Research Mentor(s):	Gregory N. Parsons/Chemical Engineering Michael Stewart/Chemical Engineering Jeong-Seok Na/Chemical Engineering Jay Lewis/Research Triangle Institute Jonathan McDaniel/Research Triangle Institute
Title of Presentation:	Composition and Electrical Characterization of Organic Solar Cells

Solar cell technologies may become an economical energy substitute if photovoltaic devices (PVDs) become cost competitive with current power sources. The advancement of inorganic solar cells is hindered by high production costs for efficient energy output as compared to more traditional energy systems in use. Organic PVDs may provide solar industries with more efficient, cost comparative devices. In conjunction with Research Triangle Institute, an organic PV device was constructed using thin film depositions of ITO, TiO₂, photosensitive polymer, and metal electrode. Using a light source that approximated the irradiance of the sun, current (I) through the device was measured as a function of applied voltage (V) supplied to the sample. The I-V measurements were taken under bright and dark conditions in order to determine electrical properties based on the respective plotted I-V data. These results are providing insight regarding electrical characterization techniques needed to fully assess PVD operation and performance for further laboratory experiments.

Student Author(s):	Gilliam, Jennifer K.
Home Institution:	North Carolina State University
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Chemical and Biomolecular Engineering
Research Mentor(s):	Steven W. Peretti/Chemical and Biomolecular Engineering
Title of Presentation:	Computer Simulation of the Structure of Efflux Pumps to Increase Whole-Cell Biocatalytic Efficiency for Reactions Involving Aromatic Compounds

The overall goal of this project was to characterize root-nodulation division (RND) efflux pumps. This was done by empirically defining the efflux pump Ttg, as it has a low selectivity making it easier to characterize. Characterization of this pump will elucidate how structural modification can vary selectivity to create an industrially viable product such as p-hydroxybenzoate (PHBA) from toluene through cellular metabolism. Computer simulations were first conducted to predict structure, then to simulate specific mutations in order to predict how structure affects efflux rates and antibiotic resistance. By making simple modifications, such as adding positive charges to select residues, the pump should be more selective toward negatively charged compounds. This should allow for more efficient production of PHBA and a more effective diffusion of toluene through the membrane. Large concentrations of toluene have been shown to inhibit the formation of PHBA, therefore a Ttg mutant must have lower selectivity for toluene. By changing the selectivity of Ttg, product recovery will be easier. Since efflux pumps have also been shown to affect antibiotic resistance, it was also important to characterize them to potentially deactivate their structural ability to resist antibiotics. Thus, it was necessary to see how these mutants reacted on antibiotic plates, then to characterize the pumps’ structure-activity relationships. This will become useful in both enhancing whole-cell conversion of toluene as well as for subsequently deactivating efflux pumps for antibiotic efficiency.

Student Author(s):	Gutierrez, Erika R.
Home Institution:	North Carolina State University
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Chemical and Biomolecular Engineering
Research Mentor(s):	Saad Khan/Chemical and Biomolecular Engineering Sachin Talwar/Chemical and Biomolecular Engineering
Title of Presentation:	Molecular Interactions between Comb-like Associative Polymer and Silica Nanoparticles

Hydrophobically modified associative polymers are a new class of environmentally benign water soluble polymers with exciting potential applications as viscosity modifiers in industrial applications including aircraft anti-icing fluids, oil drills, drug delivery, coatings and personal care products. The polymer contains pendant hydrophobes that form a network of inter- and intramolecular hydrophobic associations in an aqueous media. The properties that the hydrophobic associations exhibit can be further tailored by adding silica nanoparticles (fumed silica). The motivation for using fumed silica is its flexibility in surface group modification. Rheology, or flow behavior, was used to examine the molecular interactions and microstructure of these solutions. In particular, the interest is to explore the effects of hydrophobic vs. hydrophilic functional groups of silica nanoparticles on solution rheology and to examine the dominant interaction mechanism between associative polymer and silica nanoparticles. The studied effects are a) silica nanoparticle surface area, b) silica nanoparticle concentration, c) capped hydrophobes, and d) temperature. This study will further facilitate the development of polymeric systems with tailored nanoparticulate functional properties for different applications.

Student Author(s):	Hoffman, Catherine M.
Home Institution:	North Carolina State University
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Civil, Construction, and Environmental Engineering
Research Mentor(s):	Joel J. Ducoste/Civil, Construction, and Environmental Engineering Detlef R. Knappe/Civil, Construction, and Environmental Engineering
Title of Presentation:	UV Initiated Advanced Oxidation Processes for the Degradation of Phenol

The use of ultraviolet (UV) initiated advanced oxidation processes (AOPs) is becoming a very attractive option for degrading organic contaminants, such as phenol, in the water treatment industry. The main objective of this research is to confirm the reaction pathway and quantify the reaction kinetics of the photochemical degradation of phenol in UV initiated AOPs using hydrogen peroxide (H₂O₂) as the source of hydroxyl radicals. Using deionized water spiked with phenol and four of its oxidation intermediates (benzoquinone, catechol, hydroquinone, and resorcinol), a method for separating and measuring the concentrations of these chemicals in aqueous solution was developed using high performance liquid chromatography (HPLC). After exposing samples of phenol to varying concentrations of H₂O₂ and UV doses in a collimated beam apparatus and quenching any remaining H₂O₂, the concentrations of the five compounds will be measured by HPLC. We expect that our results will allow us to optimize the UV/ H₂O₂ AOPs. These results will be used in combination with further research to model these processes using Computational Fluid Dynamics and to provide a detailed design process for evaluating and designing photoreactor systems for the degradation of contaminant species.

Student Author(s):	Kelley, Dana K. Yoo, Caroline K.
Home Institution:	Oberlin College
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Wood and Paper Science Biomedical Engineering
Research Mentor(s):	Lucian A. Lucia/Wood and Paper Science Elizabeth Loboa/Biomedical Engineering
Title of Presentation:	Novel Fibrous Biomaterial Scaffolds for Tissue Engineering Using Human Adipose-Derived Adult Stem Cells

Carboxymethyl cellulose (CMC) is an anionic, water-soluble, natural polysaccharide. This material is non-toxic, biocompatible, hydrophilic and can be chemically and physically modified. Because of the aforementioned positive traits it is believed that CMC can be used as a scaffolding material to support the adhesion and viability of human mesenchymal stem cells (hMSCs) for future tissue engineering constructs. CMC scaffolds were manufactured using by treating bleached pulp with sodium hydroxide and chloracetic acid, and then formed under 1 PSI for 3 and 9 hours. Their surface characteristics, average pore size and porosity were measured. Human MSCs were seeded on CMC scaffolds and evaluated for adhesion and viability. It was hypothesized that because of the hydrophilic nature of the material, as well as the large pore size and porosity, cells would be able to adhere to and retain viability on these scaffolds.

Student Author(s):	Kubinski, Susan R.
Home Institution:	Arizona State University
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Chemical Engineering
Research Mentor(s):	Mari Chinn/Biological and Agricultural Engineering
Title of Presentation:	Converison of Hardwood Paper Pulp into Ethanol by Separate Enzymatic Hydrolysis/Fermentation and Simultaneous Saccharification and Fermentation

Lignocellulosic substrates such as corn stover, switchgrass and wood chips, hold great potential to serve as renewable feedstocks for fuel ethanol production. Cellulase enzymes and conversion process parameters are key to the hydrolysis of substrates to sugars and downstream fermentation. The overall goal of this work was to evaluate the key conditions and techniques for effective separate enzymatic hydrolysis/fermentation (SHF) and simultaneous saccharification and fermentation (SSF). Specific objectives were to 1) Examine the effects of substrate loading (2.5, 5 and 7.5% w/v), liquid medium (acetate buffer and yeast/peptone medium), temperature (37ºC and 50ºC), and time (0-120 hours) on saccharification efficiency of cellulase and glucosidase enzymes during conversion of hardwood paper pulp and 2) Measure the growth capabilities and ethanol yields of Ethanol Red yeast on sacharified hardwood paper pulp in SHF and SSF. Reducing sugars were measured as estimates of substrate conversion and ethanol concentrations were measured using an enzyme linked assay. It was determined that a substrate loading of 7.5% w/v in yeast peptone medium (10 g/L yeast extract and 20 g/L proteose peptone) hydrolyzed at 50ºC for 48 hours produced the greatest amount of reducing sugars. SHF was accomplished by adding a 2.5% v/v inoculum (~2 OD) of Ethanol Red yeast to yeast peptone medium and supernatant produced by hydrolysis (~20 g/L of reducing sugars). For SSF, Ethanol Red yeast inoculum (2.5% v/v) was added during hydrolysis at 37ºC. At this time, further analyses of both SHF and SSF are required before sugar conversion and ethanol yields may be reported.

Student Author(s):	McArthur, Timothy H. Cornelius, Carrie
Home Institution:	North Carolina A&T State University
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Textiles
Research Mentor(s):	Marian McCord/Textiles
Title of Presentation:	The Use of Atmospheric Plasma Desizing on Cotton Fabrics

Polyvinyl Alcohol (PVA) is used as a size to reduce yarn breakage during the weaving process. Using traditional wet processing methods, size is removed after the weaving process by a series of hot water baths containing oxidizing agents such as hydrogen peroxide. While PVA size can be partially recovered and reused, wastewater treatment can be costly. Recently, there have been numerous efforts to find ways to reduce the energy consumption associated with the desizing process, including the use of atmospheric pressure plasma treatment as an aid in the desizing process, to improve desizing efficiency and reduce the number of wash cycles or wash temperature. In previous studies, some atmospheric plasma treatments have been shown to decrease the molecular weight of PVA, thus enhancing the solubility of the PVA in water. In this project, atmospheric pressure plasma pretreatment was compared with hydrogen peroxide pretreatment of 14% PVA sized woven PET/cotton blend fabrics for desizing efficiency. The amount of size removed was determined immediately after the plasma treatment, after a subsequent room temperature wash, and again after a hot water wash. The gas types used in the plasma include: 100% He, 99% He 1%O2, 98% He 2% O2, 99% He 1% CF4, and 98% He 2% CF4, and the exposure time varied from thirty seconds to ten minutes. Scanning electron microscopy was used to compare the surface changes due to desizing treatments. Tensile testing was conducted to analyze changes in fabric modulus. An analysis of the cost of conventional vs. plasma-aided desizing was performed.

Student Author(s):	McLaughlin, Stephen Chin, Paul
Home Institution:	North Carolina State University
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Chemical Engineering
Research Mentor(s):	David Ollis/Chemical Engineering
Title of Presentation:	Photocatalytic Decolorization of Reactive Black 5 Using Thin Films of Titanium Dioxide

Photocatalytic oxidation has the potential for “self-cleaning” applications ranging from outdoor statues to window glass. These “self-cleaning” surfaces are produced from thin layers of photoactive materials which can break down organic and inorganic pollutants. The photocatalyst titanium dioxide (TiO2) is widely used because prior research has shown it to be most effective and non-toxic. Filter paper and Reactive Black 5 dye were chosen as model compounds to test the “self-cleaning” properties of TiO2 and to determine an effective way to deposit thin TiO2 layers. The photocatalytic decolorization of Reactive Black 5 on filter paper was examined. Round filter paper, 37 mm in diameter, was sequentially dipped into a 10 weight percent Degussa P25 TiO2 and 0.001 M (1mM) Reactive Black 5 solutions. The average TiO2 thickness was calculated as 0.3-0.7 mm. The dye-TiO2 coated filters were illuminated for a period of 1-4 hours in a photoreactor containing eight General Electric 20W UVA blacklight-blue fluorescent lamps with a peak emission of 365 nm. Decolorization of dye was observed visually and photographically using a Canon Powershot a520 digital camera. Generally, the more TiO2 deposited on the filter paper or the higher the incident UVA irradiance on the dye-TiO2 coated filters, the faster the decolorization occurred. Therefore the rate of photo-oxidation by TiO2 is proportional to light intensity and to the thickness of the TiO2 layer.

Student Author(s):	Montañez, Gabriela
Home Institution:	Arizona State University
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Chemical Engineering
Research Mentor(s):	Peter K. Kilpatrick/Chemical & Biomolecular Engineering
Title of Presentation:	Extraction and Fractionation of Sclareol from Green Clary Sage Concrete using Generally Recognized as Safe (GRAS) Ester Solvents

Sclareol extracted from the Clary sage plant (Salvia sclarea) offers a variety of health benefits. Not only is it an antioxidant, it is antimicrobial and anti-inflammatory. It is also shown to have cytotoxic effects on cells affected by leukemia. Our primary goal in this research was to optimize the yield and purity of extracting sclareol into the ester solvent ethyl lactate. Ethyl lactate is a generally recognized as safe (GRAS) ester solvent and therefore is much safer than hexane, which is used currently. A green Clary sage extract containing 50% w/w sclareol was dissolved in ethyl lactate in different concentrations. The starting concentrations were above the solubility limit of pure sclareol (95%) in ethyl lactate. Our results indicate that yield and purity of sclareol are enhanced as temperature and time of extraction are increased. We also measured the impurities upon extraction and filtration and the ability to reduce these impurity levels by fractionating the extracted material by Gas AntiSolvent precipitation with carbon dioxide. We report on the results of these experiments.

Student Author(s):	Panczyk, Mark M.
Home Institution:	New Jersey Institute of Technology
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Chemical Engineering
Research Mentor(s):	Martin A. Hubbe/Wood and Paper Science
Title of Presentation:	Saving Energy by Using Aqueous Chemistry and Reducing the Water Content of Paper Before It is Dried

Approximately 2000 megajoules of energy are required to evaporate water during the production of one ton of paper. Though there is potential to save some of this energy by the use of chemical additives, it is only recently that there has been a test method suitable for rapid and reliable estimation of such effects in the laboratory. A modified water retention value (WRV) test, using centrifugation, has been utilized to estimate how much water can be pressed from papermaking fibers. The hypothesis for the present work is that the ability of fibers to hold onto water following various treatments ought to depend on the charged nature of cellulosic surfaces. Results of WRV tests, supplemented by dewatering rate tests (freeness tests) and zeta potential measurements showed significant effects even at very low levels of addition of soluble chemicals, including acid, poly-aluminum chloride, poly-diallyldimethylammonium chloride, cationic acrylamide copolymer, and sequential combinations of cationic polymers and colloidal silica. In some cases, the WRV and dewatering results could be explained in terms of surface charge phenomena, which are expected to cause cellulosic materials either to

repel each other or to stick together.

Student Author(s):	Paul, Evan M.
Home Institution:	NC A&T
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Chemical Engineering
Research Mentor(s):	Peter Fedkiw/Chemical Engineering
Title of Presentation:	Methanol Permeability in Direct Methanol Fuel Cell Membranes

For measuring the permeability of methanol through Direct Methanol Fuel Cell (DMFC) membranes calibration curves of methanol concentration versus their refractive index were measured. The morality range was from 0 to 1 molar and all the refractive indices were taken at 20 Celsius and 589 nanometers. Samples were then taken from a diffusion-cell apparatus, refractive indices measured, and introduced back into the equation from the calibration curve to find the exact concentration at the recorded time. The methanol permeability was then calculated for each membrane and compared to the standard and most widely used membrane Nafion.

Student Author(s):	Petschke, Eric
Home Institution:	North Carolina State University
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Chemical and Biomolecular Engineering
Research Mentor(s):	Gregory N. Parsons/Chemical and Biomolecular Engineering
Title of Presentation:	Fabrication of a Grätzel Cell for Testing New Porphyrin-based Photovoltaics

With oil prices regularly increasing, the exploitation of clean, renewable energy resources has become important as an alternative to fossil fuels. Photovoltaics can be used to convert energy from the sun into electric current by absorbing photons of light to generate excitons – electron-hole pairs – and then separating those charge carriers at a conductive contact or bulk interface. In order to develop a method to test new porphyrin-based photovoltaic materials, a known process was adapted to produce a working Grätzel cell. Grätzel cells are promising photovoltaic devices because they use low cost raw materials and do not require elaborate manufacturing techniques. To produce these Grätzel cells, a titanium dioxide paste was stamped onto an indium tin oxide-glass substrate. The sample was sintered and then porphyrin was deposited onto the titanium dioxide through a solution process. Iodine-containing electrolyte solution! was then added as a charge carrier to move charges from the porphyrin film to a metal contact. A key problem to date has been methodologies to control adhesion between the indium tin oxide and the titanium dioxide. However, physical vapor deposition and solution-based deposition prior to application of the titanium dioxide paste may produce a titania underlayer that will increase adhesion between the titanium dioxide and indium tin oxide.

ent Author(s):	Teran, Alexander A.
Home Institution:	Johns Hopkins University
Program:	NSF Sustainability, Energy, and Engineering REU – Chemical Engineering
Department(s):	Chemical and Biomolecular Engineering
Research Mentor(s):	Hasan Jameel/Wood & Paper Science
Title of Presentation:	Effect of Filler/Additives on Enzyme Recycle in Conversion of Waste Paper to Ethanol

Ethanol is a source of renewable energy produced by the fermentation of sugars from various sources of biomass. Currently, much of the ethanol produced in the U.S. is from the starch fraction of corn. Corn is not an ideal feedstock because it is an energy intensive food crop which leads to an unfavorable energy balance for the ethanol it yields. There is a need to find better feedstocks to produce ethanol. Waste paper is an abundant cellulosic commodity that could serve as a feedstock to produce ethanol. One way to convert cellulosic material into ethanol is through enzymatic hydrolysis, however the cost of the enzymes often makes this method economically unattractive. By increasing the recycle of the enzyme, the overall process costs are reduced. This research was undertaken to examine the effects of the additives/contaminants in waste paper such as chemicals and fillers on enzyme recovery after hydrolysis and explore the practicality of waste paper as a feedstock for ethanol production. Enzymatic hydrolysis was done using an enzyme system with a 9:1 ratio of cellulase (ACE P150) to cellobiase (Novozyme 188). The optimum conditions were 1500 units/ g OD pulp with 5% consistency at 55 C for 24 hours. Several different recycle methods were tested to find the highest enzyme activity recovery including filtrate only, residual solids only, both filtrate and residual solids, as well as recycling both with supplemental cellulase. Recycling of both the filtrate and the residual solids proved most effective. Initial activity levels could be re-attained by the addition of supplemental enzyme upon recycling at levels of ½ the initial enzyme charge. Plain copy paper and cellulosic pulp with calcium carbonate were tested because they are the most common additives in mixed office waste. Data from these experiments will be presented.

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