Chemical Engineering Commons^™

Atmospheric Mercury Chemistry: Detection, Kinetics, And Mechanism, Na Mao

Dissertations

The presence of mercury in the environment is of global concern due to its toxicity. The atmosphere is an important transient reservoir for mercury released by human activities and natural sources. The knowledge of atmospheric mercury chemistry is critical for understanding the global biogeochemical cycle. In the atmosphere, mercury primarily exists in three forms: gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particulate-bound mercury (PBM). Over the last decade, the existing knowledge of mercury cycle has dramatically changed: (1) There has been increasing evidence that current detection methods do not accurately quantify gaseous oxidized mercury and a technique which …

A Detailed Parameter Study Into The Dermal Absorption Of Chemical Warfare Agents And The Effects Of Pharmacokinetics, Koko Lear

Theses

Chemical warfare agents (CWAs) are substances of varying toxicity profiles. These chemicals exhibit complex dynamics and pose a serious health risk when released into the environment. A mathematical model based on Fick’s second law of diffusion was developed to comprehend how these compounds were absorbed into the skin. The analysis applied to both small and large doses and, successfully, predicted experimental results. This work also includes the effects of CWA physicochemical properties on evaporation and dermal absorption through the stratum corneum. A sensitivity analysis was conducted to assess the impacts of small variations in the initial dose, environmental conditions, and …

Electrochemical Synthesis Of Acetylpyrazine, Lin Mao, Dong-Fang Niu, Shuo-Zhen Hu, Xin-Sheng Zhang

Journal of Electrochemistry

Acetylpyrazine is naturally presented in hazelnuts, peanuts, and sesame seeds. As an important food additive, it is widely used in baked foods, meat, sesame and tobacco. At the same time, acetylpyrazine is also an important pharmaceutical intermediate, which is used in the syntheses of anti-tuberculosis drugs, anti-tumor, anti-malaria, anti-viral, antibacterial and treatments of epilepsy, pain and Parkinson’s drugs. At present, the synthesis methods of acetylpyrazine include oxidation method, multi-step method and Grignard reagent method, which have the disadvantages of low yield, cumbersome process, severe reaction conditions and high cost. In this study, acetylation of pyrazine was used to synthesize acetylpyrazine …

Electrocatalytic "Volcano-Type" Effect Of Nano-Tio2 (A)/(R) Phase Content In Pt/Tio2-CnX Catalyst, Ai-Lin Cui, Yang Bai, Hong-Ying Yu, Hui-Min Meng

Journal of Electrochemistry

The relationship between the electrochemical activity of fuel cell catalysts and Pt particle size, as well as the catalyst support and co-catalyst is still unclear. In this work, FESEM, XRD, BET, TEM and CV techniques were adopted to investigate the effects of TiO₂ anatase (A)/rutile (R) phases content on the electrochemical activity of Pt electrocatalyst. The results showed that the anatase-rutile phase transformation occurred during the heat treatment of TiO₂ at 700 ~ 900 ^oC accompanied by the growth of two-phase crystalline size, and anatase was completely transformed into rutile at 900 ^oC. TEM results revealed …

Electroanalytical Measurements Of Lanthanum (Iii) Chloride In Molten Calcium Chloride And Molten Calcium Chloride And Lithium Chloride, Mark H. Schvaneveldt, Ranon Fuller, Devin Rappleye

Faculty Publications

Cyclic voltammetry (CV), square wave voltammetry (SWV) and other electroanalytical methods have been applied to molten chloride salts to study metal ion behavior. These studies have been useful for understanding and optimizing the electrowinning of metals. Notable ions that have been studied are rare earth and actinide metal ions in LiCl-KCl salts. However, the behavior of lanthanum (La³⁺) ions in some molten chlorides or chloride mixtures (e.g., CaCl₂) has not been studied. CV experiments were conducted to evaluate La³⁺ behavior in CaCl₂-LiCl and CaCl₂ and were compared to La³⁺ behavior in …

Study And Improvement On Expansion Property Of Silicon Oxide, Wei-Chuan Qiao, Fang-Ru Li, Jin-Lin Xiao, Li-Juan Qu, Xiao Zhao, Meng Zhang, Chun-Lei Pang, Zi-Kun Li, Jian-Guo Ren, Xue-Qin He

Journal of Electrochemistry

The silicon-based anode materials have the potential to meet the ever-increasing demand for energy density in lithium-ion batteries market owing to their high theoretical specific capacity. Unfortunately, their commercialization was hindered by the continuous volume expansion. Herein, the expansion characteristics and corresponding mechanism of the silicon oxide and graphite-silicon oxide composites were investigated by in-situ displacement detection systematically. The results showed that the expansion property was improved by material process modifications. During the de/lithiation processes of graphite, the expansion ratio in 30% ~ 50% SOC changed little because of the small interlayer spacing variation of the intercalated graphite. …

Preparation And Properties Of Gcp-Supported Palladium Particles Composite Towards Electrochemical Ammonia Synthesis, Ying-Chao Wang, Zi-Zai Ma, Yi-Fan Wu, Xiao-Guang Wang

Journal of Electrochemistry

Ammonia (NH₃) plays an essential role in agriculture and modern industries. Electrochemical fixation of nitrogen (N₂) to ammonia (NRR) under ambient conditions with renewable electricity is a promising strategy to replace the industrial Haber-Bosch method. However, it usually suffers from extremely poor ammonia yield and low Faraday efficiency due to the poor electrocatalysts. Therefore, intensive studies have been devoted to developing efficient NRR catalysts till now. Among them, palladium (Pd) can capture protons in the aqueous phase to form stable α-PdH, which balances the competitive adsorption between nitrogen and protons as well as reduces the …

Optimum Biodiesel Production Using Ductile Cast Iron As A Heterogeneous Catalyst, Nada Amr El-Khashab, Marwa Mohamed Naeem, Mai H. Roushdy

Chemical Engineering

Biofuels production become a target for many researchers nowadays. Biodiesel is one the most important biofuels that are produced from biomass using economics and modern techniques. The ductile cast iron solid waste dust is one of the wastes produced by the cast iron industry which has a bad effect on the environment. This paper investigates the possibility of reusing ductile cast iron solid waste as a biodiesel heterogeneous catalyst used in its production from sunflower waste cooking oil. Four reaction parameters were chosen to determine their effect on the reaction responses. The reaction parameters are M:O ratio, reaction time and …

Characterization Of Gas Hydrate Formation And Its Impact On Slope Stability In Offshore Environments, Sulav Dhakal

LSU Doctoral Dissertations

Natural gas hydrates (NGH) are predominantly methane hydrates formed at high pressure and low temperature conditions typically in submarine sediments and permafrost. This dissertation is focused on the submarine methane hydrates formed by upward migration of free and dissolved gas. The methane gas stored within natural hydrates has more energy potential than all the combined oil and gas resources around the world. Numerical simulation of fluid flow, heat transport, and geomechanical stresses is used to characterize and evaluate the saturation, distribution, reservoir quality, and geohazards associated with hydrate-bearing sediments. Coupled thermo-hydro-mechanical (THM) simulation of hydrate formation, dissociation, and slope stability …

Virucidal N95 Respirator Face Masks Via Ultrathin Surface-Grafted Quaternary Ammonium Polymer Coatings, Mirco Sorci, Tanner D. Fink, Vaishali Sharma, Sneha Singh, Ruiwen Chen, Brigitte L. Arduini, Katharine Dovidenko, Caryn L. Heldt, Edmund F. Palermo, R Helen Zha

Michigan Tech Publications, Part 1

N95 respirator face masks serve as effective physical barriers against airborne virus transmission, especially in a hospital setting. However, conventional filtration materials, such as nonwoven polypropylene fibers, have no inherent virucidal activity, and thus, the risk of surface contamination increases with wear time. The ability of face masks to protect against infection can be likely improved by incorporating components that deactivate viruses on contact. We present a facile method for covalently attaching antiviral quaternary ammonium polymers to the fiber surfaces of nonwoven polypropylene fabrics that are commonly used as filtration materials in N95 respirators via ultraviolet (UV)-initiated grafting of biocidal …

Aerosol Capture And Coronavirus Spike Protein Deactivation By Enzyme Functionalized Antiviral Membranes, Rollie Mills, Ronald J. Vogler, Matthew Bernard, Jacob Concolino, Louis B. Hersh, Yinan Wei, Jeffrey Todd Hastings, Thomas D. Dziubla, Kevin C. Baldridge, Dibakar Bhattacharyya

Chemical and Materials Engineering Faculty Publications

The airborne nature of coronavirus transmission makes it critical to develop new barrier technologies that can simultaneously reduce aerosol and viral spread. Here, we report nanostructured membranes with tunable thickness and porosity for filtering coronavirus-sized aerosols, combined with antiviral enzyme functionalization that can denature spike glycoproteins of the SARS-CoV-2 virus in low-hydration environments. Thin, asymmetric membranes with subtilisin enzyme and methacrylic functionalization show more than 98.90% filtration efficiency for 100-nm unfunctionalized and protein-functionalized polystyrene latex aerosol particles. Unfunctionalized membranes provided a protection factor of 540 ± 380 for coronavirus-sized particle, above the Occupational Safety and Health Administration’s standard of 10 …

The Role Of Nickel And Brønsted Sites On Ethylene Oligomerization With Ni-H-Beta Catalysts, Gabriel V.S. Seufitelli, Jason J.W. Park, Phuong N. Tran, Anthony Dichiara, Fernando L.P. Resende, Rick Gustafson

Jasper Department of Chemical Engineering Faculty Publications and Presentations

The present work studies the adsorption of ethylene on Ni-H-Beta particles to unravel the roles of nickel and Brønsted sites in the catalytic oligomerization of ethylene. Three models (i.e., two based on the Cossee-Arlman mechanism and one based on the metallacycle mechanism) are examined in terms of the nature of the active sites and the adsorption mechanism involved in the ethylene coordination step. The results are consistent with the participation of two active sites in the formation of [Ni(II)-H]+ Cossee-Arlman centers and also suggest that ethylene dissociates upon adsorption on [Ni(II)-H]+ sites. Further characterization of Ni-H-Beta catalysts prepared at different …

A Circular Economy Approach To Improve E-Waste Recycling In California: Economic Potential And Policy Options, Kripa Shah

Master's Projects and Capstones

The higher consumption rates of electronic devices along with their short life cycles and few repair options poses a huge challenge for E-waste industries to manage them effectively. E-waste comprises of hazardous materials and toxic constituents that can affect the environment and public health through improper disposal. However, they also contain few valuable materials that, if recovered, can reduce the dependence on virgin raw materials. Circular economy has the potential to utilize these valuable materials and gain environment and socio-economic benefits. The research explains how the adoption of a circular economy approach can help improve the E-waste recycling in California …

Shape Memory Polymer Foaming With Tunable Interconnectivity Using Off-The-Shelf Foaming Components, Natalie Marie Petryk

Theses - ALL

The ability to tune pore structures of gas-blown polyurethane shape memory polymer (SMP) foams easily and safely could improve their outcomes as hemostatic dressings or tissue engineering scaffolds and overall commercialization efforts. Incorporating physical blowing agents into the polymer mix can be used to tune pore size and interconnectivity without altering foam chemistry. Enovate (HFC-254fa) is a commonly used physical blowing agent in gas-blown foams, but the Environmental Protection Agency (EPA) considers its use unacceptable because it is a hydrofluorocarbon that contributes to global warming. Here, off-the-shelf solvents accepted for use by the EPA, acetone, dimethyoxymethane (methylal), and methyl formate, …

Hybrid Double Network Cryogels Scaffold For Repair Of Local Cartilage Defect, Kaixiang Zhang

Theses - ALL

Trauma or repeated injury to the joint can result in focal cartilage defects, which significantly increase the risk of osteoarthritis. Cartilage being avascular has limited self-healing capacity. The current method for treating cartilage defects at early stages involves implantation of autologous chondrocytes with or without a scaffold through invasive surgery; however, invasive surgery can bring pain to patients and post-operative infection risks. Therefore, injectable and biodegradable biomaterials have piqued people's interest. In the current research, we designed a hybrid double network (DN) cryogel by combining multi-arm PEG acrylate and alginate as two networks and crosslinking them at -20°C. Through different …

Engineering Metal-Oxide Interface By Depositing Zro2 Overcoating On Ni/Al2o3 For Dry Reforming Of Methane, Baitang Jin, Shiguang Li, Yuzi Liu, Xinhua Liang

Chemical and Biochemical Engineering Faculty Research & Creative Works

Zirconium oxide (ZrO₂) was deposited onto Ni/Al₂O₃ catalyst as overcoating by atomic layer deposition (ALD) for dry reforming of methane (DRM). High-temperature heating during H₂-reduction could transform the ALD-prepared ZrO₂ thin film to tetragonal phase and crack the encapsulating layer on Ni sites, which constructed a beneficial Ni-ZrO_x interface. Interfacial surface oxygen vacancies on ZrO₂ overcoating were induced by the partial reduction of ZrO₂ surface during high-temperature H₂ reduction, with the assistance of Ni. During DRM, the interfacial oxygen vacancies enhanced CO₂ activation by dissociating CO_{2 …}

Controlling The Emission Of Volatile Platinum Oxides To The Vapor Phase In Diesel Oxidation Catalysts, Arnab Ghosh

Nanoscience and Microsystems ETDs

Pt-based catalysts are used for the treatment of emissions from vehicles, particularly in Diesel oxidation catalysts (DOCs). Three-way catalysts are treated at temperatures ranging from 950℃-1050℃ while DOCs are aged at 800℃ for 50 hrs. At 800°C, Pt reacts with O₂ to form PtO₂ which has a high vapor pressure and can be transported through the vapor phase. These accelerated aging conditions lead to the formation of large Pt particles causing a loss of catalytic activity. In this thesis, we used model thin-film catalysts that made it possible to quantify the emission of Pt to the vapor phase …

Particle Formation And Thermal Radiation In Laminar Diffusion Flames With Applications To Energy And Materials, Phillip Irace

McKelvey School of Engineering Graduate Student Theses & Dissertations

Fossil fuels supply over 80% of the world’s primary energy, and if current policy and technology trends continue, global energy and energy-related carbon dioxide (CO2) emissions are predicted to increase for at least several decades owing to population and economic growth, leading to serious concerns regarding global warming. Natural gas releases less CO2 than other fossil fuels (e.g., coal and oil) and can help meet future CO2 emission targets. Natural gas combustion, however, has poor radiation heat transfer when compared to other fossil fuels owing to its low propensity for soot formation, making it difficult to use as a drop-in …

A Drift-Flux Model For Upward Two-Phase In Pipes With High Velocity Flows, Woochan Lee

LSU Doctoral Dissertations

This study proposes the evaluation and development of a drift-flux model for upward two-phase high-velocity flow in large diameter pipes. A case where the proposed model is applicable is WCD (Worst-Case-Discharge) calculations for offshore wells. WCD assumes relatively larger pipe diameters and higher flow rates than the flow experiments at laboratory conditions utilized to validate and develop most of the flow models available in the literature.

Most of the two-phase flow models describe flow regime transitions as discrete processes by assigning the required void fraction or velocity for each flow regime transition. Therefore, for each flow regime, flow-regime-dependent correlations or …

Photocatalytic Degradation Of Organic Contaminants By Titania Particles Produced By Flame Spray Pyrolysis, Noah Babik

Theses and Dissertations

Advanced oxidation of organic pollutants with TiO2 photocatalysts is limited due to the wide bandgap of TiO2, 3.2 eV, which requires ultraviolet (UV) radiation. When nanosized TiO2 is modified by carbon doping, charge recombination is inhibited and the bandgap is narrowed, allowing for efficient photodegradation under visible light. Here, we propose a flame spray pyrolysis (FSP) technique to create TiO2. The facile process of FSP has been successful in preparing highly crystalline TiO2 nanoparticles. Using the same procedure to deposit TiO2 onto biochar, the photocatalyst was doped by the carbonaceous material. The morphology, crystalline and electronic structure of the FSP …