Chemical Engineering Commons^™

Corrosion Rate Prediction In Frp-Concrete Repair, Mohammad A. Khawaja

USF Tampa Graduate Theses and Dissertations

Research has proven that wrapping structural elements with fiber-reinforced polymers (FRPs) slows down chloride-induced corrosion rate but does not stop it. Although FRP has been used for corrosion repair for over 40 years, predictive corrosion rate models for FRP-concrete systems are limited in literature. This dissertation presents an oxygen diffusion-based predictive framework to estimate corrosion rate in FRP-concrete systems.

The dissertation has three main components. First, a core framework that is referred to as Khawaja-Sen-Bhethanabotla (KSB) model. In the KSB model, statistical methods were used to extend experimental data on oxygen permeation coefficients. These data were for one and two …

Plasmonic Photocatalysis For Gas-Phase Degradation Of Total Volatile Organic Compounds: Theory, Experimentation, And Catalyst Stability, Amaury P. Betancourt Iii

USF Tampa Graduate Theses and Dissertations

Plasmonic nanomaterials have become a strong contender for improving the efficiency of photocatalytic degradation of air pollutants. This study demonstrates an easy and scalable fabrication method, employing electron beam evaporation and rapid thermal annealing, for producing plasmonic photocatalysts. Samples were made by either coating silver on, or layering silica-protected (i.e., silica-coated) or unprotected (i.e., uncoated) silver beneath, the photocatalyst (either zinc oxide or titanium dioxide). Stability and catalytic performance for gas-phase toluene degradation was assessed by monitoring total volatile organic compound (TVOC) concentration versus ultraviolet-A (UV-A) illumination time in a recirculating batch reactor (plate-type flow-through). Samples were characterized using a …

An Investigation Of Cross-Links On Crystallization And Degradation In A Novel, Photocross-Linkable Poly (Lactic Acid) System, Nicholas Baksh

USF Tampa Graduate Theses and Dissertations

Polymeric molecular structure consists of repeating units bonded together. Mechanicalproperties can be altered without affecting chemical makeup by altering the number of these units. Small molecules can be introduced and/or polymers can be modified to form bonds between molecular chains. Cross-linking, as this is called, also introduces mechanical variation with minimal effects on chemical composition. Lastly, polymer chains reorient themselves in response to intermolecular forces. This temperature dependent response is known as crystallization. Although chemistry is unaltered, mechanical properties can depend highly on the percent of the sample that is crystallized.

Cross-linking is known to enhance the mechanical properties of …

Biogas Upgrading Via Solid Resin-Based Amine Sorbents, Olusola Johnson

USF Tampa Graduate Theses and Dissertations

Biogas is a valuable renewable energy generated from anaerobic digestion of biodegradable organic matter. It is applicable as fuel in vehicles, for the generation of electricity, industrial heating, or as raw material to produce chemicals, liquid fuels, syngas, and compressed natural gas (CNG). Carbon dioxide (CO2) and methane (CH4) are the major components in biogas, with a trace amount of contaminants, including hydrogen sulfide (H2S), water vapor (H2O), nitrogen (N2), ammonia (NH3), oxygen (O2), carbon monoxide (CO), halides, volatile organic compounds (VOCs), siloxanes, and hydrocarbons.

The source of biogas, which is anaerobic digestion of different organic matter or landfill decomposition, …

Low-Grade Kaolin Clay Natural Resource For Use As A Supplementary Cementitious Material In Structural Concrete Elements, Brandon X. Lorentz

USF Tampa Graduate Theses and Dissertations

At the turn of the century, low-grade kaolin clay (LGK) was presented as a widely available and potential natural resource of supplementary cementitious materials (SCM) for producing high performance concretes. In using LGK as an SCM, clinker production is reduced, aiding environmental concerns with associated CO2 emissions. These types of clays have very heterogeneous mineralogy and microstructural characteristics, causing unique influences on concrete structural and flow performance, although these influences are not well understood. This research studies LGK natural to the state of Florida and assesses their potential use as high performance SCM.

Ten kaolin clays were obtained through a …

Cactus-Based Mucilage As A Natural Dispersant For Crude Oil Spills, Fei Guo

USF Tampa Graduate Theses and Dissertations

Oil spills are a critical threat to the marine environment, and the spilled oil as a source of pollution can have long-term adverse effects on the marine ecosystem. Traditional mechanical clean-up operations have apparent advantages for dealing with small and medium-scale oil spills. For large-scale oil spills, dispersants are a practical and minimally influential approach to the environment. As the dispersant components are iteratively updated, dispersants become more efficient and safer. However, the toxicity of the dispersants remains a significant impediment to their application. An efficient and non-toxic dispersant is increasingly becoming a requirement.

The cactus mucilage extracts studied in …

Effects Of Reservoir Conditions And Trace Co-Contaminant Gases On Geological Carbon Sequestration, Ram Kumar

USF Tampa Graduate Theses and Dissertations

Geological carbon sequestration in a saline formation is a promising technology for large-scale carbon dioxide (CO2) mitigation. Several factors such as temperature, pressure, salinity, hydraulic conductivity, and mineralogy of a formation affect the CO2 sequestration in saline formations. These factors can vary widely depending upon the type of formation or the degree of heterogeneity within a formation. In addition to these properties of the repositories, the CO2-rich flue gas streams captured from point sources often contains small amounts of impurities such as sulfur oxides (SOx) and nitrogen oxides (NOx), which may have serious implications on the chemistry of the repositories …

Responsive Coatings And Functional Systems From Pectin Polysaccharides, Zeinab Veisi

USF Tampa Graduate Theses and Dissertations

Pectin polysaccharides provide promising potential as all-natural, non-toxic “green” coatings. Pectin polysaccharides have been drawing growing attention as elements of stimuli-responsive systems and as source materials for functionalized robust coatings. They can be extracted from several natural sources and are intrinsically biocompatible. The majority of the applications of pectin gels require a better understanding of the properties of thin layers of gels at surfaces and interfaces. Despite the prevalence of bulk gels of pectin, coatings of pectin have not been reported. In bulk hydrogels, swelling of polymer networks is controlled by a diffusion limited transport process in which the rate …

Carbon Dioxide Adsorption Using Solid Amine Sorbents, Umadevi Gopalakrishnan

USF Tampa Graduate Theses and Dissertations

Biogas, being rich in methane, can be used as a fuel for various end uses such as electricity generation, compressed natural gas (CNG), production of liquid fuels, industrial heating, etc. CO₂ is the major contaminant in biogas (30–50%) along with other impurities such as NH₃, H₂S, and water. CO₂ in the biogas decreases the heating value of biogas. Natural gas pipelines and vehicle use require high purity (> 95%) CH₄. There are many commercial techniques available for CO₂ removal from biogas such as such water scrubbing (WS), chemical scrubbing (CS) using …

Effect Of Promoter (Mn) On The Performance Of Sba-15 Supported Iron Catalysts For High Temperature Fischer-Tropsch Synthesis, Sreya Mariya Seby

USF Tampa Graduate Theses and Dissertations

Development of an effective High Temperature Fischer-Tropsch Synthesis (HTFTS) catalyst is of interest in process intensification that combines methane reforming with long chain hydrocarbon production. Literature indicates iron catalysts supported on mesoporous silica performed relatively well in high temperature applications. In this work, we investigated the effect of manganese promoter on iron catalysts for FTS at 430 °C as it was known from previous studies that manganese promotion could enhance the CO conversion with higher hydrocarbon yields. Also, the effect of temperature on FTS activity was evaluated by testing the base and promoted Fe/SBA-15 catalysts for temperature ranging from 370 …

Sorption Of Benzene, Tolueneand Ethylbenzeneby Plasticized Pema And Pema/Pmma Sensing Films Using Aquartz Crystal Microbalance (Qcm) At 298.15k, Deekshitha Adapa

USF Tampa Graduate Theses and Dissertations

Detection of volatile organic compounds (VOC’s) in the environment is important for human health and wellness. Long term exposure of certain VOC’s like benzene, toluene, ethylbenzene and xylene (BTEX) has a severe effect on human health. There are techniques such as gas chromatography, photo ionization, and mass spectroscopy that are time consuming, require gas sampling and are ineffective in real time sensing in air. Acoustic wave devices such as surface acoustic wave (SAW) devices can be used for sensing BTEX compounds in both vapor and liquid phase. The quartz crystal microbalance (QCM) is a low-frequency acoustic wave device, which can …

Enhanced Co2 Conversion By The Simultaneous Doping Of Co, Fe, And Mn In The B-Site Of A Lanthanum Perovskite, Adela E. Ramos

USF Tampa Graduate Theses and Dissertations

There is a pressing need for carbon dioxide (CO₂) mitigation technologies as increasing emissions continue to threaten our environment. Carbon capture and storage (CCS) alone would not be able to achieve temperature rise below 2 °C. In addition, CCS cost increases considerably for power generation and other industries where CO₂ separation is necessary. Conversion of CO₂ to usable products is the most economical and feasible solution as it could offset CO₂ separation cost. Liquid fuels are an attractive route since it is a commodity used globally and demand increases with population and economic growth. Conversion …

Sorption Of Benzene, Toluene And Ethylbenzene By Plasticized Poly (Ethyl Methacrylate) Using Quartz Crystal Microbalance At 298.15k, Kiranpreet Kaur

USF Tampa Graduate Theses and Dissertations

Quartz crystal microbalances (QCM) are chemical sensors used for liquid and vapor sensing. In this thesis work, plasticized poly (ethyl methacrylate) (PEMA) coated QCM was used to study sorption behavior of benzene, ethylbenzene and toluene in respective polymer at 298.15K. Poly (ethyl methacrylate) (PEMA) is a promising polymer with solubility parameter close to BTEX compounds, but it's glassy and rigid nature at room temperature make it less sensitive. The addition of plasticizers (Diisononyl cyclohexane-1,2-dicarboxylate (DINCH) and Diisooctyl azelate (DIOA)) lowers the glass transition temperature, provides flexibility and thus increases the free volume of the polymer to enhance analyte sorption. In …

Effect Of Heating On Heat Capacity Of Vegetable Oils Used For Biofuel Production, Sailee Nitin Nagpurkar

USF Tampa Graduate Theses and Dissertations

Biodiesel has become a major renewable fuel for diesel engines particularly from various waste sources. New biodiesel production technologies are emerging with data demands for efficient process design. This project highlights the data requirements, gaps in the thermo-physical property data, and consolidation of experimental and estimation methods for effective process development. Knowing the thermodynamic properties of a substance is important in order to know what process or procedures it has to go under. The aim of this project is to assess the potential of vegetable oils to serve as feedstock for biofuel production by determining their heat capacity (Cp). Such …

Photocatalytic Carbon Dioxide Conversion To Fuel For Earth And Mars, Anne J. Meier

USF Tampa Graduate Theses and Dissertations

As far as we know, we only have one planet to live on, with a delicate atmospheric system providing us safety and life. Global CO2 emissions continue to plague the environment of Earth, primarily due to the processing of fossil fuels, deforestation, and industrialization. There are several avenues of pursuing CO2 reutilization, each having their own benefits and limitations. Direct and indirect thermochemical approaches of CO2 conversion boast of efficient CO2 conversion rates but have limitations associated with the use of renewable hydrogen and high temperatures of operation. The work in this dissertation investigates low temperature photocatalytic CO2 conversion, a …

Defect Laden Metal Oxides And Oxynitrides For Sustainable Low Temperature Carbon Dioxide Conversion To Fuel Feedstocks, Debtanu Maiti

USF Tampa Graduate Theses and Dissertations

The current energy and environmental scenario in the world demands acute attention on sustainable repurposing of waste CO2 to high value hydrocarbons that not only addresses the CO2 mitigation problem, but also provides pathways for a closed loop synthetic carbon cycle. Difference in the scales of global CO2 emissions (about 40 Gtpa, 2017) and the carbon capture and sequestration (CCS) facilities (estimated cumulative 40 Mtpa, 2018) provokes active research on this topic. Solar thermochemical (STC) and visible light photocatalysis are two of the most promising routes that have garnered attention for this purpose. While STC has the advantages of high …

Sustainable Production Of Bio-Based Succinic Acid From Plant Biomass, Enlin Lo

USF Tampa Graduate Theses and Dissertations

Succinic acid is a compound used for manufacturing lacquers, resins, and other coating chemicals. It is also used in the food and beverage industry as a flavor additive. It is predominantly manufactured from petrochemicals, but it can also be produced more sustainably by fermentation of sugars from renewable feedstocks (biomass). Bio-based succinic acid has excellent potential for becoming a platform chemical (building block) for commodity and high-value chemicals.

In this study, we focused on the production of bio-based succinic acid from the fiber of sweet sorghum (SS), which has a high fermentable sugar content and can be cultivated in a …

Dynamic Modeling Of An Advanced Wastewater Treatment Plant, Komal Rathore

USF Tampa Graduate Theses and Dissertations

Advanced wastewater treatment plants have complex biological kinetics, time variant influent rates and long processing times. The modeling and operation control of wastewater treatment plant gets complicated due to these characteristics. However, a robust operational system for a wastewater treatment plant is necessary to increase the efficiency of the plant, reduce energy cost and achieve environmental discharge limits. These discharge limits are set by the National Pollutant Discharge Elimination System (NPDES) for municipal and industrial wastewater treatment plants to limit the amount of nutrients being discharged into the aquatic systems.

This document summarizes the research to develop a supervisory operational …

Promoter Effects On Iron-Based, Sba-15 Supported Ultra-High Temperature Fischer- Tropsch Catalysts, David P. Weber

USF Tampa Graduate Theses and Dissertations

Promoter effects on SBA-15 supported iron Fischer-Tropsch catalysts were investigated for their potential to improve high temperature catalyst performance. FTS catalysts promoted by manganese (0.15%-1.4%), copper (0.15%-1%), and potassium (0.5%-3%), with all percentages stated on the basis of mass percentage of final catalysts, were prepared and tested at 430°C and ambient pressure in a fixed bed reactor. Manganese showed the ability to promote the FT reaction, increasing both the CO conversion and the average chain length of hydrocarbon products. Compared to the unpromoted catalyst composed only of iron supported on SBA-15, 1.4%Mn (mass) promotion of 15% (mass) iron on SBA-15 …

Conversion Of Biomass To Liquid Hydrocarbon Fuels Via Anaerobic Digestion: A Feasibility Study, Ahmad Naqi

USF Tampa Graduate Theses and Dissertations

The use of biomass as a potential feedstock for the production of liquid hydrocarbon fuels has been under investigation in the last few decades. This paper discusses a preliminary design and a feasibility study of producing liquid hydrocarbon fuels from biomass through a combined biochemical and thermochemical route. The process involves anaerobic digestion (AD) of the biodegradable portion of the biomass to produce methane rich gas. The methane rich biogas stream is purified by removing contaminants and upgraded to liquid hydrocarbon fuel in a gas to liquid facility (GTL) via thermochemical conversion route. The biogas conversion involves two major steps: …

Supported Perovskite-Type Oxides: Establishing A Foundation For Co2 Conversion Through Reverse Water-Gas Shift Chemical Looping, Bryan J. Hare

USF Tampa Graduate Theses and Dissertations

Perovskite-type oxides show irrefutable potential for feasible thermochemical solar-driven CO₂ conversion. These materials exhibit the exact characteristics required by the low temperature reverse water-gas shift chemical looping process. These properties include structural endurance and high oxygen redox capacity, which results in the formation of numerous oxygen vacancies, or active sites for CO₂ conversion. A major drawback is the decrease in oxygen self-diffusion with increasing perovskite particle size. In this study, the La_0.75Sr_0.25FeO₃ (LSF) perovskite oxide was combined with various supports including popular redox materials CeO₂ and ZrO₂ along with more abundant …

The Control Of Water Contaminants Assisted By Natural Materials, Wen Zhao

USF Tampa Graduate Theses and Dissertations

Natural materials can be used to remove water contaminants by applying proper physical, chemical, and biological water treatment processes. This study involves using natural materials, as they are considered to be more environmentally benign and cost-effective than synthetic materials. This dissertation concentrates on monitoring five major water quality parameters—ammonia, fluoride, turbidity, pH, and fecal indicator bacteria (FIB) —in two major applications where clean water is needed. The focus is on meeting the water quality requirements for each contaminant. The overall objective of this study is to control the levels of ammonia in aquaculture wastewater, and adjust fluoride, turbidity, pH, and …

Molecular-Size Selective Zeolite Membrane Encapsulated Novel Catalysts For Enhanced Biomass To Liquid (Btl) Processes, Ummuhan Cimenler

USF Tampa Graduate Theses and Dissertations

80% of energy usage in the word comes from fossil fuels (coal, oil, natural gas) and among the fossil fuels, oil is the most consumed energy source especially in transportation. However, due to concerns about energy demand and energy sustainability, global warming and dependency on foreign oil, generation of renewable fuels is crucial for transportation. Biomass to Liquid (BTL) is a promising process available to produce renewable liquid fuels. BTL fuels have great potential to meet the growing demand for liquid fuels, mitigating climate change, and providing value to rural areas. However, there are two major challenges with biofuels produced …

Sorption Of Benzene, Dichloroethane, Chloroform And Dichloromethane By Polyethylene Glycol, Polycaprolactone And Their Copolymers At 298.15 K Using A Quartz Crystal Microbalance, Abhijeet Radhakrishna Iyer

USF Tampa Graduate Theses and Dissertations

Quartz crystal microbalances (QCM) are acoustic wave sensor systems which are used majorly for vapor and liquid sensing. QCM come under the category of thickness shear mode (TSM) sensors. There are several methods to study organic vapor sensing; the QCM method is the one that offers the highest sensitivity and generates the most data. Solubilities of benzene, dichloroethane, chloroform and dichloromethane in polyethylene glycol (PEG), polycaprolactone (PCL), and several di-block PEG/PCL copolymers at 298.15 K are reported. There are literature data available for most of the solvents in the homopolymers PEG and PCL but no literature data is available for …

Light Olefin Production By Cracking Nannochloris Oculata Microalgae Using Aluminosilicate Catalysts, Gaurav Goyal

USF Tampa Graduate Theses and Dissertations

The global demand and sustainability concerns for producing light olefins encouraged researchers to look for an alternative and sustainable feedstock. Alkenes, such as ethene, propene and butene, are known as light olefins. Olefins are the backbone of the chemical industry because they serve as the chemical building blocks for the manufacture of polymers, fibers, and numerous organic chemicals. Feedstocks such as naphtha, natural gas and liquefied petroleum gas (LPG) are currently used for producing light olefins, but they are non-renewable and hence unsustainable. In contrast, biomass as a potential feedstock for the production of fuels and chemicals is renewable. Microalgae, …

Catalytic Upgrading Of Biogas To Fuels: Role Of Reforming Temperature, Oxidation Feeds, And Contaminants, Nada Elsayed

USF Tampa Graduate Theses and Dissertations

Global energy demands are constantly increasing and fossil fuels are a finite resource. The shift towards alternative, more renewable and sustainable fuels is inevitable. Furthermore, the increased emissions of greenhouse gases have forced a pressing need to find cleaner, more environmentally friendly sources of fuel. Biomass energy is a promising alternative fuel because it offers several important advantages. It is a renewable energy form, it comes from many sources and produces biogas (CH₄ and CO₂). Furthermore, it can have a zero carbon footprint; this is due to the fact that the carbon produced is from the same …

Photocatalytic Reduction Of Co2 With Tunable Bandgap And Bandedge Materials, Thuhuong T. Ngo

USF Tampa Graduate Theses and Dissertations

Solar energy is a sustainable resource which has substantial potential to meet the increasing demand for renewable energy. Though there has been some success in harvesting solar energy for electricity production, converting solar energy to chemical energy as fuels is still a challenge due to low efficiency.

Since the discovery of TiO₂ photocatalysts for splitting water (4) and reducing CO₂ (5) to form useful chemical feedstock such as H₂, CO and CH₄, much research has been done to increase the efficiency of photocatalysts. However, the current conversion efficiency of photocatalysts remains low (~5%) (6, …

Biomarker Detection At Risk Forecasting Level Using Metal-Enhanced Fluorescence Combined With Surface Acoustic Wave, Jun Liu

USF Tampa Graduate Theses and Dissertations

In this paper, metal-enhanced fluorescence (MEF) technique is used to lower the detection limit of carcinoembryonic antigen (CEA) which is able to be utilized in forecasting the risk of having certain kinds of cancers, especially colon and rectal cancer. By incubating silver nanocubes (Ag NCs) on the surface of the chips, the detection limit goes down to below 1ng/mL of CEA. Also, when combining MEF with surface acoustic wave (SAW) devices, the incubation time between antigen and antibody will decrease significantly with the fluorescence signal keeping similar or higher level.

The Design And Testing Of A Novel Batch Photocatalytic Reactor And Photocatalyst, Shawn Sasser

USF Tampa Graduate Theses and Dissertations

With an ever-increasing human population, the importance in having sustainable energy resources is becoming increasingly evident, as the current energy habits have brought about massive atmospheric pollution in the form of CO₂ emissions, resulting in a rise in the average global temperature. To battle the effects of climate change, many alternative energy resources have been investigated. Among these, photocatalytic conversion of CO₂ to renewable hydrocarbon fuels such as methane and methanol is one of the most desirable, as it provides the opportunity to utilize the sun’s energy to convert CO₂ to renewable fuels. The work in this …

Nano-Photonic Waveguides For Chemical And Biomedical Sensing, Surya Venkatasekhar Cheemalapati

USF Tampa Graduate Theses and Dissertations

In this dissertation, advances in the fields of Photonics, and Plasmonics, and specifically, single cell analysis and waveguide sensing will be addressed. The first part of the dissertation is on Finite Difference Time Domain (FDTD) optimization and experimental demonstration of a nano-scale instrument that allows sensing at the cellular and subcellular levels. A new design of plasmonic coupler into a nanoscale waveguide is proposed and optimized using FDTD simulations. Following this, a subcellular nanoendoscope that can locally excite fluorescence in labelled cell organelles and collect the emitted fluorescent light for detailed spectrum analysis is fabricated and tested. The nanoendoscope has …