Chemical Engineering Commons^™

Investigation Of Oxygen Reduction Reaction In Carbon-Based Electrocatalysts, Andrew Mason

Honors Program: Senior Projects (Public)

In the modern era, some global challenges are energy storage conversion. To find sustainable solutions to this problem, researchers have turned to renewable energy resources. An example of promising energy generation devices is fuel cell. Fuel cells are electrochemical systems that convert the chemical energy of the fuel to electrochemical potential that can be used as direct current (dc) generators. Although these technologies are very attractive, they are known to be expensive due to high cost of catalysts and concerns regarding their energy densities. Fuel cells composed of two electrodes, namely cathode and anode and electrolyte separating the oxidizing agents …

Fabrication Of Polyvinylidene Fluoride Hollow Fiber Membranes For Membrane Distillation, Abdullah Al Balushi

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Desalination technologies can help humanity tap into the most abundant source of water on earth, seawater; however, desalination is an energy-demanding process. Most of the desalination plants worldwide use conventional energy resources; therefore, desalination leaves a large carbon footprint. Solar energy is an available source of energy that can be harvested and integrated into desalination systems.

Membrane distillation (MD) is an emerging purification technology that many offers many advantages over traditional desalination systems. For starters, it can utilize low-grade thermal energy to drive the separation, therefore, it can be suitably integrated into the solar-thermal energy scheme. Additionally, MD can be …

Modeling The Interplay Between Photosynthesis, Co2 Fixation, And The Quinone Pool In A Purple Non-Sulfur Bacterium, Adil Alsiyabi

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Rhodopseudomonas palustris CGA009 is a purple non-sulfur bacterium (PNSB) that can fix CO₂ and nitrogen or break down organic compounds for its carbon and nitrogen requirements. Light, inorganic, and organic compounds can all be used for its source of energy. Excess electrons produced during its metabolic processes can be exploited to produce hydrogen gas or biodegradable polyesters (polyhydroxybutyrate). A genome-scale metabolic model of the bacterium was reconstructed to study the interactions between photosynthesis, carbon dioxide fixation, and the redox state of the quinone pool. A comparison of model-predicted flux values with published in vivo MFA fluxes resulted in predicted …

Bioproduction Of Adipic Acid Using Engineered Pseudomonas Putida Kt2440 From Lignin-Derived Aromatics, Howard Willett

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Current industrial synthesis of adipic acid is nonrenewable and depends on a carcinogenic starting material, benzene. Biocatalysis with an engineered microorganism could turn a renewable feedstock into a value-added chemical such as adipic acid. Here we engineered P. putida KT2440 to transform lignin-derived aromatics, coumarate and ferulate, into adipic acid. Lignin is a recalcitrant plant biopolymer burned for thermal energy. Conversion of lignin into a value-added chemical will improve the efficiency of lignocellulose processing plants. The best performing engineered KT2440 strain produces 2.52 mM adipate at a 9.5% (mole/mole) yield. This was achieved by the genetic insertion of non-natural biosynthetic …

Fibrinogen, Factor Xiii And Fibronectin: A Biophysical And Kinetic Characterization Of Their Interactions, Frank Fabian

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

The development of recombinant-based liquid fibrin tissue sealants having enhanced hemostatic and wound healing properties will involve understanding as yet not well characterized interactions between fibrinogen, fibrin (Fbn) factor XIII, thrombin and fibronectin. We study these phenomena in the context of comparing plasma derived fibrinogen to recombinant fibrinogen (rFI) produced in the milk of transgenic cows. An abundance of purified γγ and γγ’ FI subspecies enables detailed study of γγ or γγ’ biomonomer and their respective Fbn biopolymer formation as having different substrate behaviors of activated plasma derived factor XIII (pFXIIIa₂b₂). High pressure size exclusion (HPSEC) …

Biomethane Production From Distillery Wastewater, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Distillery wastewater treatment is a great ecological problem, for example, India produces 2.7 billion liters of alcohol that results in 40 billion liters of wastewater. However, this material can be seen as a resource since 11 million cubic meters of biogas at 60% methane could be produced in addition to cleaning the water. The distillery has two options of what to do with the biogas. The first is to use the biogas to fuel the distillery making the production plant more energy efficient and removing some of the need to buy natural gas. The other is to upgrade the biogas …

Improving The Distribution And Use Of Biogas By Conversion To Methanol, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

In this technology review, the process of turning an average biogas into methanol will be presented. The purpose is to find a better method of transporting the energy contained within biogas so that it may be used in industry as a value added product. The first step is removal of hydrogen sulfide, a corrosive chemical that can breakdown mechanical parts. The second step is carbon capture and conversion of the biogas into hydrogen. The final step is the hydrogenation of carbon dioxide into methanol using a copper catalyst and an alcohol co-catalyst.

Comparative Kinetic Modeling Of Growth And Molecular Hydrogen Overproduction By Engineered Strains Of Thermotoga Maritima, Raghuveer Singh, Rahul Tevatia, Derrick White, Yaşar Demirel, Paul H. Blum

Department of Chemical and Biomolecular Engineering: Faculty Publications

Thermotoga maritima is an anaerobic hyperthermophilic bacterium known for its high amounts of hydrogen (H₂) production. In the current study, the kinetic modeling was applied on the engineered strains of T. maritima that surpassed the natural H₂ production limit. The study generated a kinetic model explaining H₂ overproduction and predicted a continuous fermentation system. A Leudking-Piret equation-based model predicted that H₂ production by Tma200 (0.217 mol-H₂ g^–1-biomass) and Tma100 (0.147 mol-H₂ g^–1-biomass) were higher than wild type (0.096 mol-H₂ g^–1 -biomass) with reduced rates of maltose utilization. …

Extraction Of Astaxanthin From Engineered Camelina Sativa Seed Using Ethanol-Modified Supercritical Carbon Dioxide, Liyang Xie, Edgar B. Cahoon, Yue Zhang, Ozan Ciftci

Department of Food Science and Technology: Faculty Publications

Natural astaxanthin, a high-value carotenoid that is currently extracted mainly from marine organisms, was extracted from engineered camelina seed using ethanol-modified supercritical carbon dioxide (SC-CO₂) for the first time, and compared with hexane and accelerated solvent extraction using hexane and ethanol. Response surface methodology (RSM) based on central composite rotatable design was employed to investigate the effect of pressure (30–45 MPa), temperature (40–60 °C), and ethanol concentration (10–35%, w/w). RSM-optimized conditions (41.6 MPa, 36.6 °C and 42.0% ethanol concentration) predicted the astaxanthin concentration as 437 μg/g oil, whereas the actual concentration was 421 ± 14 μg/g oil. Astaxanthin …

Uncoupling Fermentative Synthesis Of Molecular Hydrogen From Biomass Formation In Thermotoga Maritima, Raghuveer Singh, Derrick White, Yaşar Demirel, Robert Kelley, Kenneth Noll, Paul H. Blum

Department of Chemical and Biomolecular Engineering: Faculty Publications

When carbohydrates are fermented by the hyperthermophilic anaerobe Thermotoga maritima, molecular hydrogen (H₂) is formed in strict proportion to substrate availability. Excretion of the organic acids acetate and lactate provide an additional sink for removal of excess reductant. However, mechanisms controlling energy management of these metabolic pathways are largely unexplored. To investigate this topic, transient gene inactivation was used to block lactate production as a strategy to produce spontaneous mutant cell lines that overproduced H₂ through mutation of unpredicted genetic targets. Single-crossover homologous chromosomal recombination was used to disrupt lactate dehydrogenase (encoded by ldh) with …

Title: Investigation Of Oxidative Reduction Reactions In Carbon-Based Electrocatalysts Presentation, Andrew Mason, Siamak Nejati, Shayan Kaviani

UCARE: Research Products

The expense of commonly used electrocatalysts such as Platinum and Palladium, make many battery technologies and electrochemical reactions cost-prohibitive. A new group of promising low-cost catalysts is doped carbon complexes. These materials need further development to reach the same activity as traditional catalysts. But by examining the Oxidative Reduction Reactions (ORR) of various carbon complexes, desirable characteristics and geometries can be identified and enhanced. For this comparative analysis, a series of Carbon Nanotube (CNT) and Graphene Complexes were tested.

Sustainable Waste-To-Energy Technologies: Bioelectrochemical Systems, Rami Ziara, Bruce Dvorak, Jeyamkondan Subbiah

Department of Civil and Environmental Engineering: Faculty Publications

The food industry produces a large amount of waste and wastewater, of which most of the constituents are carbohydrates, proteins, lipids, and organic fibers. Therefore food wastes are highly biodegradable and energy rich. Bioelectrochemical systems (BESs) are systems that use microorganisms to biochemically catalyze complex substrates into useful energy products, in which the catalytic reactions take place on electrodes. Microbial fuel cells (MFCs) are a type of bioelectrochemical systems that oxidize substrates and generate electric current. Microbial electrolysis cells (MECs) are another type of bioelectrochemical systems that use an external power source to catalyze the substrate into by-products such as …

Sustainable Clean Coal Technology With Power And Methanol Production, Xiaomeng Wang

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

The coal-based chemical process is still indispensable in modern society due to the worldwide vast reserves and popular price of coal. Power generation and chemical production from coal still play an important role in the global chemical industrial market. Electricity generation and chemical production from coal is still the trend as long as the coal is plentiful and inexpensive. Modern chemical industry aims at sustainability and hence the development of clean coal technologies is critical.

Coal-based methanol economy, as an attractive liquid transportation fuel as well as an essential intermediate chemical feedstock, can fill a possible gap between declining fossil …

Genetic Code Expansion In Biochemical Investigations And Biomedical Applications, Nanxi Wang

Department of Chemistry: Dissertations, Theses, and Student Research

Genetic code expansion provides a powerful tool for site-specific incorporation of unnatural amino acids (unAAs) with novel biochemical and physiological properties into proteins in live cells and organisms. To achieve this, a nonsense codon suppression system, which consists of an orthogonal aminoacyl-tRNA synthetase (aaRS) and tRNA pair that specifically decodes a nonsense codon (e.g., amber codon and quadruplet codon) with an unAA but do not “cross talk” with their endogenous counterparts, was established. This Ph.D. thesis presents our efforts on evolution and application of nonsense codon suppression systems for biochemical and biomedical investigations.

In Chapter 1, a brief overview of …

Remediating 1,4-Dioxane-Contaminated Water With Slow-Release Persulfate And Zerovalent Iron, Ann Kambhu, Megan Gren, Wei Tang, Steve D. Comfort, Clifford Harris

Nebraska Water Center: Faculty Publications

1,4-dioxane is an emerging contaminant that was used as a corrosion inhibitor with chlorinated solvents. Metal-activated persulfate can degrade dioxane but reaction kinetics have typically been characterized by a rapid decrease during the first 30 min followed by either a slower decrease or no further change (i.e., plateau). Our objective was to identify the factors responsible for this plateau and then determine if slow-release formulations of sodium persulfate and Fe⁰ could provide a more sustainable degradation treatment. We accomplished this by conducting batch experiments where Fe⁰-activated persulfate was used to treat dioxane. Treatment variables included the timing …

Sugar Versus Lipid For Sustainable Biofuels, Yaşar Demirel

Yaşar Demirel Publications

Introduction

First‐generation biofuels, namely, ethanol and biodiesel, have led to far reaching impact on the peoples’ life world‐wide.[1] However, they inter-fere with the food supply chain and may not be sustainable although some of the biomass are converted to biofuels after those biomasses have met the human needs. Still, the first‐generation–based biofuels have proved that sugar and lipid platforms can be an answer to energy security and global warming concerns without the need for new infrastructure for feedstock delivery as well as for biomass‐to‐biofuel conversion tech-nologies. At the same time, we are discovering and assessing the long‐term environmental im-plications on …

Effects Of Post Eviction Resettlement On Land-Use And Cover Change In Uganda’S Oil Exploration Areas, Joseph Ssekandi, John Mburu, Oliver Wasonga, Laban Macopiyo, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

Evaluation of the changes in land use and land cover change (LULCC) in respect to oil exploration across the Albertine region in Uganda has been focused around the exploration areas and protected areas, with no attention to the potential impacts of evictees’ activities on resettled areas. This study used LANDSAT images to analyze the land use and land cover changes (LULCC) among the period before eviction (2002 and 2005) at the climax of eviction and resettlements (2005-2011), and during the post-resettlement period (2011-2015) to quantify the impacts of resettlements on the environment. LANDSAT images were processed using ERDAS IMAGINE software …

Use Of Natural Ores As Oxygen Carriers In Chemical Looping Combustion: A Review, Michael J. Matzen, Jessica Pinkerton, Xiaomeng Wang, Yaşar Demirel

Department of Chemical and Biomolecular Engineering: Faculty Publications

Chemical looping combustion (CLC) has gained considerable ground in energy production due to its inherent carbon capture with a minimal energy penalty. The choice of metal oxide used as an oxygen carrier (OC) in CLC has a substantial weight on the overall efficiency of energy production as well as the ultimate cost per MW. While much work has gone into manufacturing synthetic OCs with high fuel conversions, harsh operating conditions and process limitations cause some unavoidable loss of the oxygen carrier. With low production costs and minimal conditioning required, natural ores have grown in interest as cheap alternative oxygen carriers. …

Characterization Of Molecular Communication Based On Cell Metabolism Through Mutual Information And Flux Balance Analysis, Zahmeeth Sayed Sakkaff

School of Computing: Dissertations, Theses, and Student Research

Synthetic biology is providing novel tools to engineer cells and access the basis of their molecular information processing, including their communication channels based on chemical reactions and molecule exchange. Molecular communication is a discipline in communication engineering that studies these types of communications and ways to exploit them for novel purposes, such as the development of ubiquitous and heterogeneous communication networks to interconnect biological cells with nano and biotechnology-enabled devices, i.e., the Internet of Bio-Nano Things. One major problem in realizing these goals stands in the development of reliable techniques to control the engineered cells and their behavior from the …

Methanol And Dimethyl Ether From Renewable Hydrogen And Carbon Dioxide: Alternative Fuels Production And Life-Cycle Assessment, Michael J. Matzen, Yaşar Demirel

Yaşar Demirel Publications

In this work we investigate two renewably based alternative fuels; methanol and dimethyl ether. The ultimate feedstocks for production are wind-based electrolytic hydrogen and carbon dioxide captured from an ethanol fermentation process. Dimethyl ether production was modeled in ASPEN Plus using a previously simulated methanol production facility. The facilities use 18.6 metric tons (mt) of H₂ and 138.4 mt CO₂ per day. Methanol is produced at a rate 96.7 mt/day (99.5 wt%) and dimethyl ether is produced at a rate of 68.5 mt/day (99.6 wt%). A full comparative life-cycle assessment (cradle-to-grave) of both fuels was conducted to investigate …

Alginate Hydrogels As Three-Dimensional Scaffolds For In Vitro Culture Models Of Growth Plate Cartilage Development And Porcine Embryo Elongation, Taylor D. Laughlin

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

The establishment of in vitro culture models utilizes tissue engineering principles to design functional mimics of in vivo environments in vitro. Advantages for the use of in vitro culture models include ethical alleviation of animal models for therapeutic testing, cost efficiency, and a greater ability to study specific mechanisms via a systematic, ground-up approach to development. In this thesis, alginate hydrogels are utilized in the development of in vitro culture models of porcine embryo elongation and growth plate cartilage development. First, the effect of scaffold and modifications to the scaffold were explored in both projects. In order to modulate …

Sustained Cell Differentiation Of 2d H9 Human Embryonic Stem Cells Into Mesenchymal Stem Cells, Hannah M. Christian

UCARE: Research Products

This experiment consisted of the controlled differentiation of H9 embryonic stem cells to mesenchymal stem cells. Though this experiment was repeated twice and improvement was seen in these repetitions, the cells were only able to be partially differentiated. However, the morphology of the differentiated cells is similar to those of healthy adult mesenchymal stem cells.

The progression of the differentiation can be seen in the microscope slide photos below. Throughout the differentiation, there occurred a decrease in cell survival and reduction of cell growth, but an increase in mesenchymal stem cell morphology. Throughout the last week of the differentiation, very …

Optimizing Chemical & Rheological Properties Of Rejuvenated Bitumen, Dominic Nguyen, Hamzeh Haghshenas Fatmehsari, Santosh Kommidi, Yong-Rak Kim

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Bitumen has long been a material used in the construction of roadways, yet new pavement only consists of low fractions of recycled materials due to poor compatibility of aged bitumen and new materials. Thus, rejuvenators, chemical additives, have been used in an attempt to re-balance the chemical composition and restore the physical properties of aged bitumen back to its virgin state. A fundamental understanding of how one particular rejuvenator, soybean oil, revitalizes bitumen was investigated using a multi-scale approach.

Fourier-transform infrared spectroscopy (FTIR) was used to determine the changes in chemical properties of pure and rejuvenated virgin and aged samples. …

Brain Tumor In A Dish: Glioma/Astrocyte Co-Cultures As A Model For In Vitro Studies, Erin Eickman, Christina Wilson, Srivatsan Kidambi

UCARE: Research Products

This study seeks to engineer an in vitro co-culture model to elucidate the role of glioma-astrocyte interactions on molecular changes in the tumor microenvironment. The use of patterned co-cultures created with polyelectrolyte multilayers and micromolding in capillaries will allow tthe investigation of cell-cell communication. This study will lead to better understanding of the role of healthy cells in cancer progression and potential treatment options.

Novel Nitroxyl Radical Synthesis, Max Meier

UCARE: Research Products

The purpose of this research is to synthesize a novel compound, 2,2,6,6-dispirocyclobutylpiperidine- 4-one (P), for use as an oxidation reactant to form the corresponding nitroxyl radical. This is to be conducted using a reliable method for a variety of 2,2,6,6-tetrasubstituted piperidine-4-one compounds as detailed by Sakai et al. [3]. Sakai uses a variety of 6-member cyclic ketones, which are quite stable. It was attempted to use 4-member cyclic ketones to research the effectiveness of 2,6-substitution using a less stable carbonyl compound. Cyclobutanone and 3-oxycetanone were used as candidates for this reaction. Both are delicate, expensive ketones.

Investigation Of A Nanoparticle Delivery System For Micronutrients In Corn, Zully Perez Sierra, Zachary P. Stewart, Hendrik J. Viljoen

UCARE: Research Products

Pheroid Nanoparticle Delivery System1 • Cost effective for plant applications • Safe – multi-lamellar lipid system derived mostly from soybeans • Versatile – payloads delivered range from micronutrients to antibiotics Micronutrient Deficiency • Caused by the immobility of micronutrients through the plant. • Leads to malnutrition children in poor countries2 • As fertilizers deliver nutrients, only small percentage obtained by plant. Purpose of Nanoparticle Delivery System • Increase plant micronutrient content and yield • Reduces the effects of run-of, overuse and pollution Other Nano-Fertilizer Trials • Desert plant results – in a foliar application versus irrigation application, the foliar nano-fertilizer …

Ionic Driven Embedment Of Hyaluronic Acid Coated Liposomes In Polyelectrolyte Multilayer Films For Local Therapeutic Delivery, Stephen Lawrence Hayward, David Francis, Matthew J. Sis, Srivatsan Kidambi

UCARE: Research Products

The ability to control the spatial distribution and temporal release of a therapeutic remains a central challenge for biomedical research. Here, we report the development and optimization of a novel substrate mediated therapeutic delivery system comprising of hyaluronic acid covalently functionalized liposomes (HALNPs) embedded into polyelectrolyte multilayer (PEM) platform via ionic stabilization. The PEM platform was constructed from sequential deposition of Poly-LLysine (PLL) and Poly(Sodium styrene sulfonate) (SPS) “(PLL/SPS)4.5” followed by adsorption of anionic HALNPs. An adsorption affinity assay and saturation curve illustrated the preferential HALNP deposition density for precise therapeutic loading. (PLL/SPS)2.5 capping layer on top of the deposited …

Protein-Targeted Corona Phase Molecular Recognition, Gili Bisker, Juyao Dong, Hoyoung D. Park, Nicole M. Iverson, Jiyoung Ahn, Justin T. Nelson, Markita P. Landry, Sebastian Kruss, Michael S. Strano

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Corona phase molecular recognition (CoPhMoRe) uses a heteropolymer adsorbed onto and templated by a nanoparticle surface to recognize a specific target analyte. This method has not yet been extended to macromolecular analytes, including proteins. Herein we develop a variant of a CoPhMoRe screening procedure of single-walled carbon nanotubes (SWCNT) and use it against a panel of human blood proteins, revealing a specific corona phase that recognizes fibrinogen with high selectivity. In response to fibrinogen binding, SWCNT fluorescence decreases by >80% at saturation. Sequential binding of the three fibrinogen nodules is suggested by selective fluorescence quenching by isolated sub-domains and validated …

Noninvasive Measurement Of Electrical Events Associated With A Single Chlorovirus Infection Of A Microalgal Cell, Seung-Woo Lee, Eun-Hee Lee, Gerhard Thiel, James L. Van Etten, Ravi Saraf

Department of Chemical and Biomolecular Engineering: Faculty Publications

Chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1) contains a viral-encoded K⁺ channel imbedded in its internal membrane, which triggers host plasma membrane depolarization during virus infection. This early stage of infection was monitored at high resolution by recording the cell membrane depolarization of a single Chlorella cell during infection by a single PBCV-1 particle. The measurement was achieved by depositing the cells onto a network of one-dimensional necklaces of Au nanoparticles, which spanned two electrodes 70 μm apart. The nanoparticle necklace array has been shown to behave as a single-electron device at room temperature. The resulting electrochemical field-effect transistor …

Sustainability Assessment For Energy Systems And Chemical Process Industries, Michael J. Matzen

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Sustainability has become an important factor in the chemical process and energy industries with a strong drive for process improvements towards more environmentally conscious solutions. However, there are many ways of defining sustainability and even more ways of trying to determine how sustainable a process is. This work looks into applying a conjunction of tools including; process simulation, multi-criteria decision matrices and life-cycle assessment to more quantitatively determine sustainability metrics. We have applied these tools for the production of electricity, methanol and dimethyl ether. A novel method of electricity production, in chemical looping combustion (CLC), was used that inherently involves …