Tunable Nanocomposite Membranes For Water Remediation And Separations, 2017 University of Kentucky
Tunable Nanocomposite Membranes For Water Remediation And Separations, Sebastián Hernández Sierra
Theses and Dissertations--Chemical and Materials Engineering
Nano-structured material fabrication using functionalized membranes with polyelectrolytes is a promising research field for water pollution, catalytic and mining applications. These responsive polymers react to external stimuli like temperature, pH, radiation, ionic strength or chemical composition. Such nanomaterials provide novel hybrid properties and can also be self-supported in addition to the membranes.
Polyelectrolytes (as hydrogels) have pH responsiveness. The hydrogel moieties gain or lose protons based on the pH, displaying swelling properties. These responsive materials can be exploited to synthesize metal nanoparticles in situ using their functional groups, or to immobilize other polyelectrolytes and biomolecules. Due to their properties, these …
Pore-Confined Carriers And Biomolecules In Mesoporous Silica For Biomimetic Separation And Targeting, 2017 University of Kentucky
Pore-Confined Carriers And Biomolecules In Mesoporous Silica For Biomimetic Separation And Targeting, Shanshan Zhou
Theses and Dissertations--Chemical and Materials Engineering
Selectively permeable biological membranes composed of lipophilic barriers inspire the design of biomimetic carrier-mediated membranes for aqueous solute separation. This work imparts selective permeability to lipid-filled pores of silica thin film composite membranes using carrier molecules that reside in the lipophilic self-assemblies. The lipids confined inside the pores of silica are proven to be a more effective barrier than bilayers formed on the porous surface through vesicle fusion, which is critical for quantifying the function of an immobilized carrier. The ability of a lipophilic carrier embedded in the lipid bilayer to reversibly bind the target solute and transport it through …
Photocatalytic Decomposition Of Phenol Under Visible And Uv Light Utilizing Titanium Dioxide Based Catalysts, 2017 University of New Hampshire
Photocatalytic Decomposition Of Phenol Under Visible And Uv Light Utilizing Titanium Dioxide Based Catalysts, Marjorie G. Steiner
Honors Theses and Capstones
Pollution in wastewater effluvia from phenol and phenolic compounds is a common occurrence in many industrial manufacturing plants. Phenol is toxic to human beings as well as a contaminant to the environment, meanwhile, it is difficult to remove from wastewater due to its non-biodegradable nature. To boost the rate of decomposition, various catalytic approaches have been developed. With the interest of decreasing operation cost, titanium dioxide (TiO2) based catalysts have emerged as good candidates for the photocatalytic process.
In this honors project, a series of TiO2 based catalysts, including TiO2, N-TiO2, Cu-TiO2 …
Optimising The Performance Of Cement-Based Batteries, 2017 Technological University Dublin
Optimising The Performance Of Cement-Based Batteries, Aimee Byrne, Shane Barry, Niall Holmes Dr., Brian Norton
Articles
The development of a battery using different cement-based electrolytes to provide a low but potentially sustainable source of electricity is described. The current, voltage, and lifespan of batteries produced using different electrolyte additives, copper plate cathodes, and (usually) aluminium plate anodes were compared to identify the optimum design, components, and proportions to increase power output and longevity. Parameters examined include water/cement ratio, anode to cathode surface area ratio, electrode material, electrode spacing, and the effect of sand, aggregate, salts, carbon black, silica fume, and sodium silicate on the electrolyte. The results indicate that the greatest and longest lasting power can …
Fractionation And Characterization Of Lignin Streams From Genetically Engineered Switchgrass, 2017 University of Kentucky
Fractionation And Characterization Of Lignin Streams From Genetically Engineered Switchgrass, Enshi Liu
Theses and Dissertations--Biosystems and Agricultural Engineering
Development of biomass feedstocks with desirable traits for cost-effective conversion is one of the main focus areas in biofuels research. As suggested by techno-economic analyses, the success of a lignocellulose-based biorefinery largely relies on the utilization of lignin to generate value-added products, i.e. fuels and chemicals. The fate of lignin and its structural/compositional changes during pretreatment have received increasing attention; however, the effect of genetic modification on the fractionation, depolymerization and catalytic upgrading of lignin from genetically engineered plants is not well understood. This study aims to fractionate and characterize the lignin streams from a wild-type and two genetically engineered …
Investigating A Sequentially Assembled Mnox/Pt Nanocatalyst As A Potential Anode For Ethylene Glycol Fuel Cells, 2017 The British University in Egypt
Investigating A Sequentially Assembled Mnox/Pt Nanocatalyst As A Potential Anode For Ethylene Glycol Fuel Cells, Ghada El-Nowihy
Chemical Engineering
Aiming at a better electrocatalytic enhancement of ethylene glycol (EG) electrooxidation (EGO) in an alkaline medium for EG fuel cells (EGFCs), a MnOx/Pt anode was developed. A sequential layer-by-layer electrodeposition technique was employed to assemble first platinum nanoparticles (nano-Pt) directly onto the surface of a glassy carbon (GC) electrode then manganese oxide nanoparticles (nano-MnOx) were next immobilized. Field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS) were employed to evaluate the surface morphology and the bulk composition of the proposed catalyst in addition to the relative ratio of the catalyst’s ingredients. On the other hand, the catalyst …
Enzyme-Catalyzed Reactions Using Enzymes Immobilized On Non-Spherical Particles, 2017 University of New Hampshire, Durham
Enzyme-Catalyzed Reactions Using Enzymes Immobilized On Non-Spherical Particles, Alexander D. Redfearn
Honors Theses and Capstones
Modern and industrial chemical reactions often utilize enzyme-catalyzed reactions to increase product yields. Given the high cost of enzymes it is desirable to preserve the activity of the enzymes and reuse them several times. In this study, I explored the possibility of immobilizing enzymes on custom-made non-spherical SU-8 microparticles to conduct enzyme-catalyzed reactions in flow reactors. The decomposition of hydrogen peroxide using bovine liver catalase was studied due to its well-understood enzyme kinetics. Soft lithography techniques were used to synthesize prismatic SU-8 microparticles. I will discuss the progress that has been made in immobilizing the enzyme on the particle surface …
Synthesis Of Copper Oxide Nanoparticles In Droplet Flow Reactors, 2017 University of New Hampshire, Durham
Synthesis Of Copper Oxide Nanoparticles In Droplet Flow Reactors, Christopher Reilly
Honors Theses and Capstones
Synthesis of metal oxide nanoparticles within droplet flow reactors is advantageous over batch synthesis due to the elimination of concentration and temperature gradients inside the reactor and prevention of reactor fouling. We present results on the synthesis of copper oxide nanoparticles using aqueous droplets of copper acetate and acetic acid inside a bulk stream of sodium hydroxide in 1-octanol. Varying the copper acetate, acetic acid, and sodium hydroxide concentration resulted in needle-like and plate-like nanoparticles of varying sizes. The rate of mass transfer from the bulk to the droplet phase was found to increase with flow rate and addition of …
Platinum-Rhodium Alloy Electrocatalyst Activities In The Methanol Oxidation Reaction, 2017 The University of Akron
Platinum-Rhodium Alloy Electrocatalyst Activities In The Methanol Oxidation Reaction, William R. Sandorf
Williams Honors College, Honors Research Projects
This study evaluates the electrochemical activity of several compositions of platinum-rhodium alloys on carbon support to identify potential replacements for the expensive platinum electrocatalysts currently used in direct methanol fuel cells (DMFCs). The electrochemical active surface areas (ECSAs) of each sample were determined using cyclic voltammetry (CV) in a 0.5 M H2SO4 solution to normalize CV currents generated in the methanol oxidation reaction (MOR). The activity of five compositions was tested; Pt3Rh, Pt2Rh, PtRh, Pt2Rh, and Pt3Rh. 100 mg of each catalyst was synthesized at 10% by weight platinum …
A Study On The Oxidation Of Hydrogen Peroxide At Au(111) And Au(100) Electrodes, 2016 Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, 230026, China;
A Study On The Oxidation Of Hydrogen Peroxide At Au(111) And Au(100) Electrodes, Yong-Li Zheng, Jie Wei, Yan-Xia Chen
Journal of Electrochemistry
The oxidation reactions of hydrogen peroxide (H2O2) at Au(111) and Au(100) electrodes in 0.1 mol·L-1 HClO4 were investigated by using rotating disk electrode system. It was found that H2O2 could be readily oxidized to O2 at both Au(100) and Au(111) surfaces with the onset potential close to its equilibrium potential. In contrast, the onset overpotential for H2O2 reduction was above 0.4 V, while the onset overpotential for H2O2 oxidation at Au(100) was ca. 0.1 V more negative than that at Au(111), this is probably …
Chitosan/Nonahydrate Gel Derived Fe-N-Doped Porous Carbon Sheet As High-Efficient Orr Electrocatalyst, 2016 Key Laboratory of Automobile Materials, Ministry of Education and College of Materials Science and Engineering, Jilin University, Changchun 130012, China;State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130012, China);
Chitosan/Nonahydrate Gel Derived Fe-N-Doped Porous Carbon Sheet As High-Efficient Orr Electrocatalyst, Fan-Lu Meng, Xin-Bo Zhang, Jun-Min Yan
Journal of Electrochemistry
The chitosan/nonahydrate gel was used as a precursor to realize the uniform mixture of N-polymer and metal salt. After lyophilization treatment, the gel went through heat treatment and acid etch. Accordingly, the Fe-N-doped porous carbon sheet with homogenous composition and microstructure was prepared. Compared with the commercial Pt/C catalyst, the Fe-N-doped porous carbon sheet exhibited more positive onset potential and half-wave potential, higher current density, and especially, excellent durability. The power density of 318 mW·cm-2 was obtained in alkaline fuel cell with the Fe-N-doped porous carbon sheet as a cathode catalyst, which is higher than 267 mW·cm-2 with …
Synthesis Of Ultrathin Co3O4 Nanoflakes Film Material For Electrochemical Sensing, 2016 College of Electrical Engineering, Yanshan University, Qinhuangdao 066004, Hebei, China;Hebei Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004, Hebei, China.;
Synthesis Of Ultrathin Co3O4 Nanoflakes Film Material For Electrochemical Sensing, Hui-Juan Wang
Journal of Electrochemistry
Ultrathin cobalt oxide (Co3O4 ) nanoflakes film material was synthesized by using an electro-deposited cobalt layer as a raw material through a simple oxidation method and followed by a heat treatment at 350 oC. The physical characterizations of the Co3O4 nanoflakes film were performed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) technologies, and the electrochemical activity was measured by cyclic voltammetry (CV). As a promising material for electrochemical sensing, the as-synthesized ultrathin Co3O4 nanoflakes film material exhibited excellent electrochemical activity for H2O …
Stm Investigation Of Oxygen Reduction Reaction On Solid Interface In Fuel Cell, 2016 CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China;University of Chinese Academy of Sciences, Beijing 100049, China;
Stm Investigation Of Oxygen Reduction Reaction On Solid Interface In Fuel Cell, Zhen-Feng Cai, Bing Sun, Wen-Jie Jiang, Ting Chen, Dong Wang, Li-Jun Wan
Journal of Electrochemistry
An electrocatalyst for oxygen reduction reaction (ORR) is an important component for fuel cells. An investigation at interfacial electrochemical reactions toward ORR at a molecular scale benefits mechanistic understanding as well as rational design of catalysts. Scanning tunneling microscopy (STM) has been proven to be a powerful tool to monitor chemical reactions and to provide in-situ information about the interfacial electrochemical reactions at a molecular level. This review summarizes the recent STM studies in monitoring the interface processes such as morphological changes, molecular changes, reaction intermediates, and oxidation products. The prospects of future development in this field are outlined.
Syntheses Of Ag@Pd@Pt Nanoparticles With Tunable Shell Thickness For Electrochemical Oxidation Of Formic Acid, 2016 State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;
Syntheses Of Ag@Pd@Pt Nanoparticles With Tunable Shell Thickness For Electrochemical Oxidation Of Formic Acid, Xiao-Dong Lin, Du-Hong Chen, Zhong-Qun Tian
Journal of Electrochemistry
In an effort to lower cost of a catalyst, the silver (Ag) core with palladium (Pd) layer then platinum (Pt) island (Ag@Pd@Pt) nanoparticles were synthesized and the electrocatalytic activity of Ag@Pd@Pt nanoparticles on formic acid was compared with that of Au@Pd@Pt nanoparticles reported previously. The results showed that the existence of a small amount of Pt could significantly improve the activity of the catalyst. When the surface coverage of Pt approached 0.5 monolayers, the activity of Ag@Pd@Pt nanoparticles reached the maximum. Though the onset potential of the electro-oxidation was slightly more positive (about 50 mV), the overall electrocatalytic activity of …
Innovative Electrode Nanocomposites For Energy Storage And Conversion Systems, 2016 University of Tennessee, Knoxville
Innovative Electrode Nanocomposites For Energy Storage And Conversion Systems, Yiran Wang
Doctoral Dissertations
Nanocomposites emerged as suitable alternatives for electrode materials, are defined as “two or more materials with different properties remain separate and distinct on a macroscopic level within one unity and with any dimension in any phase less than 100 nm”. Recently, polymer/carbon based nanocomposites have attracted significant research interests for energy applications due to their multi-functionalities, improved structure stability and ease of production. This dissertation work focusing on the development of innovative electrode nanocomposites for proton exchange membrane fuel cell, supercapacitor and electrochromic applications.
Chapter 1 is an introduction. Chapter 2 & 3 focus on the synthesis of Pd-based nanocatalysts …
Impedance-Resolved Performance And Durability In Redox Flow Batteries, 2016 University of Tennessee, Knoxville
Impedance-Resolved Performance And Durability In Redox Flow Batteries, Alan Michael Pezeshki
Doctoral Dissertations
The realization of redox flow batteries (RFBs) as a grid-scale energy solution depends on improving the performance and lifetime of the technology to decrease the high capital costs. The electrodes are a key component in the RFB; performance enhancement is often achieved through chemical or thermal treatments of commercially available porous carbon materials.
This dissertation uses impedance spectroscopy-based methods to gain insight into performance and durability in RFBs, enabling intelligent cell design. Initial work focused on understanding the impact of improved electrode and membrane properties on system performance. An accelerated stress test was then developed that can be used to …
Effects Of Ultrasonic Transducers On Heat Transfer In Packed Particle Beds, 2016 University of Tennessee, Knoxville
Effects Of Ultrasonic Transducers On Heat Transfer In Packed Particle Beds, David Patrick Moseley
Masters Theses
The objective of this study was to determine the effects of ultrasonic transducers on heat transfer in a packed particle bed heat exchanger. Although substantial research has been devoted to ultrasound, and the associated improvements in heat transfer, data regarding the effects on packed particle beds is non-existent. This is of particular interest given the potential to improve heat transfer in a wide variety of packed particle bed systems. A 42.9% increase in the heat transfer rate was demonstrated as the result of improved fluid convection throughout the packed particle bed. Secondary effects, including acoustic cavitation, acoustic streaming and local …
Characterization Of Molecular Communication Based On Cell Metabolism Through Mutual Information And Flux Balance Analysis, 2016 University of Nebraska - Lincoln
Characterization Of Molecular Communication Based On Cell Metabolism Through Mutual Information And Flux Balance Analysis, Zahmeeth Sayed Sakkaff
Department of Computer Science and Engineering: 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 …
Lignin Maximization: Analyzing The Impact Of Different Feedstocks And Feedstock Ratios Using Organosolv Fractionation, 2016 University of Tennessee, Knoxville
Lignin Maximization: Analyzing The Impact Of Different Feedstocks And Feedstock Ratios Using Organosolv Fractionation, Marc Banholzer
Masters Theses
Over-exploitation of fossil fuels coupled with increasing pressure to reduce carbon emissions are prompting a transition from conventional petrochemical feedstocks to sustainable and renewable sourced carbon. The use of lignocellulosic biomass as a feedstock for integrated biorefining is of current high interest, as separation into its component parts affords process streams of cellulose, hemicellulose and lignin, each of which can serve as a starting point for the production of biobased chemicals and fuels. Given the large number of potential sources of lignocellulosic feedstocks, the biorefinery will need to adapt to the supplies available over a normal growing season. Of particular …
Sulfur Species Selective Adsorption Using A New Offretite Based Additive, 2016 The University of Western Ontario
Sulfur Species Selective Adsorption Using A New Offretite Based Additive, Yira Yorsirys Aponte Torrealba
Electronic Thesis and Dissertation Repository
Fluid Catalytic Cracking (FCC) unit is one of the most important conversion processes used in petroleum refineries. Nowadays, petroleum refineries, and specifically FCC units, have to be improved. New technologies must be developed to increase the refineries revenues as well to comply with environmental regulations. One area of significant concern is the necessary in-situ FCC gasoline sulfur reduction.
In this respect, this PhD dissertation proposes a new Zn-Offretite (Zn-OFF) additive for gasoline sulfur reduction via selective adsorption in FCC units. The PhD research developed covers the preparation of the Zn-OFF zeolites and their physicochemical characterization. This physicochemical …