Chemical Engineering Commons^™

Evaluating N-Benzylgalactonoamidines As Putative Transition State Analogs For Β-Galactoside Hydrolysis, Qui-Hua Fan, Susanne Striegler, Rebekah Langston, James Barnett

Chemistry & Biochemistry Faculty Publications and Presentations

Experimental evidence is provided for p-methylbenzyl-D-galactonoamidine to function as a true transition state analog for the enzymatic hydrolysis of aryl-β-D-galactopyranosides by β-galactosidase (A. oryzae). The compound exhibits inhibition constants in the low nanomolar concentration range (12–56 nM) for a selection of substrates. Along these lines, a streamlined synthetic method based on phase-transfer catalysis was optimized to afford the required variety of new aryl-β-D-galactopyranosides. Last, the stability of the galactonoamidines under the assay conditions was confirmed.

Gold-Magnetite Nanoparticle-Biomolecule Conjugates: Synthesis, Properties And Toxicity Studies, Akshay Pariti

Masters Theses

"This thesis study focuses on synthesizing and characterizing gold-magnetite optically active magnetic nanoparticle and its conjugation with biomolecules for biomedical applications, especially magnetic fluid hyperthermia treatment for cancerous tissue. Gold nanoparticles have already displayed their potential in the biomedical field. They exhibit excellent optical properties and possess strong surface chemistry which renders them suitable for various biomolecule attachments. Studies have showed gold nanoparticles to be a perfect biocompatible vector. However, clinical trials for gold mediated drug delivery and treatment studied in rat models identified some problems. Of these problems, the low retention time in bloodstream and inability to maneuver externally …

Controllable Synthesis Of Dispersed Spherical Fe3O4 Nanoparticles As Lithium-Inserted Materials, Hong-Li Zou, Wei-Shan Li

Journal of Electrochemistry

Dispersed spherical Fe₃O₄ nanoparticles were synthesized by a hydrothermal method. The influences of odecyl trimethyl ammonium bromide (DTAB) concentration on the morphology and particle size of the as-prepared Fe₃O₄ were studied. Electrochemical performance of the as-prepared sample as anode materials of lithium ion battery was investigated. It is found that the as-prepared sample exhibits superior rate performance and cycle performance. The nano-sized materials provide structural stability and favor the transfer of lithium ions.

Synthesis And Electrochemical Performance Of Nano Licopo4 By Polyol Method, Fei Wang, Yang Jun

Journal of Electrochemistry

High potential LiCoPO₄ cathode material was synthesized by polyol method. Carbon layer of ca. 3 nm thick was coated on the LiCoPO₄ surfaces by chemical vapor deposition from methylbenzene. Crystalline structure, morphology and electrochemical performance of the sample were studied by XRD, SEM, TEM, CV and galvanostatic charge/discharge curve. The synthesized material via polyol method showed a pure phase of LiCoPO₄. The LiCoPO₄/C electrode delivered a high discharge capacity of 132 mAh·g^-1 and maintained 78% of the initial capacity after 50 cycles at 0.1C rate. The two-step extraction/insertion behavior of Li⁺ in …

Aqueous Solution-Evaporation Route Synthesis And Phase Structural Research Of The Li-Rich Cathode Li1.23Ni0.09Co0.12Mn0.56O2 By In-Situ Xrd, Chong-Heng Shen, Shou-Yu Shen, Zhou Lin, Xiao-Mei Zheng, Hang Su, Ling Huang, Jun-Tao Li, Shi-Gang Sun

Journal of Electrochemistry

The Li-rich Li_1.23Ni_0.09Co_0.12Mn_0.56O₂ material was synthesized via aqueous solution-evaporation route. The structure and morphology of the material were characterized by means of XRD and SEM. The results indicated that the single particle of the product was polygonal with the size of 330 nm and the structure was layered solid solution with a certain amount of Li₂MnO₃. Electrochemical tests showed that the first discharge capacity of the Li-rich layered material was 250.8 mAh·g^-1 at 0.1C, the capacity retention was 86.5% after 40 cycles. Through in-situ XRD study …

Synthesis And Electrochemical Property Of Li2Fesio4/C Cathode Material By Solid State Method, Jiao-Li Sun, Zhi-Jiao Chen, Yi-Xiao Li, Hu Cheng

Journal of Electrochemistry

Li₂FeSiO₄/C cathode material was synthesized using Li₂SiO₃ and FeC₂O₄ as raw materials by solid state method. The structure and morphology of the material were characterized by XRD and SEM. The electrochemical properties of the material were studied by constant-current cyclic testing. The results show that Li₂FeSiO₄/C has a good electrochemical performance. The first discharge capacity of Li₂FeSiO₄/C cathode material at 30oC reached 167 mAh∙g^-1 when cycled at 10 mA∙g^-1 between 1.5 and 4.8 V.

Synthesis Of Ferrocene Copolymers And Investigation Of Their Electrochemical Properties., Alzharani Ahmed

Electronic Theses & Dissertations

Ferrocene is an organometallic compound. It is a classical metallocene consisting of two cyclopentadienyl rings bound on opposite sides of a central iron atom. Such organometallic compounds are also called sandwich compounds. Ferrocene copolymers have well known electrochemical capabilities. The main objective of this thesis is to synthesize vinyl ferrocene copolymers and test their electrochemical properties in aqueous solutions with different electrolytes (sodium nitrate, sodium perchlorate, and phosphate buffered saline). Vinylferrocene and 3-phenyl[5]ferrocenophane-1,5- dimethylene were synthesized using a Wittig reaction. Both ferrocene monomers were copolymerized with N-ethylmaleimide and N-phenylmaleimide and the resulting polymers were analyzed by Gel Permeation chromatography, IR …

Structural Characterization Of Super-Acid Oligomerized Fatty Esters., Esam Allehyani

Electronic Theses & Dissertations

Fatty acid methyl esters can be oligomerized with very strong acid catalysts - superacids such as tetrafluoroboric or triflic acid with formation of dimer and trimer fatty acids at much lower temperature, such as 80-90 °C, than what is used presently. Insight into the reaction of polymerization of fatty esters/ acids can be obtained by structural characterization. This would determine the properties of the oligomeric products and their ability to substitute currently used materials. It was presumed that dimer fatty, trimer fatty acid esters, and oligomeric fatty acid esters are produced by polymerization of fatty acid methyl esters by a …

Tin Sensitization For Electroless Plating, Xingfei Wei

Graduate Theses and Dissertations

The tin sensitization process has been used in electroless plating since 1940s Brenner and Riddell developed the electroless plating for surface metallization method. It was found to be an interesting topic to study tin sensitization for chemically controlling metal deposition on different substrates, because the tin sensitization process had critical effects on the electroless plated metal thin films. Nowadays electroless plating metal deposition is still an important method for depositing metals. It has a few advantages over the vapor deposition and electrodeposition method, such as work in an ambient condition, on nonconductive substrates, and without extra power input. Applying electroless …

Synthesis Of Pani/Nihcf Nanocomposite Particles And Eqcm Measurement Of Ion Exchange Properties In Solutions Containing Cd2+, Yu-Jiao Yang, Xiao-Gang Hao, Xu-Li Ma, Zhong-De Wang, Zhong-Lin Zhang, Nian-Chen Han

Journal of Electrochemistry

The PANI/NiHCF nanocomposite particles were synthesized on the CNTs-modified Pt substrate by one-step co-polymerization using cyclic voltammetry. Electrochemical quartz crystal microbalance (EQCM) technique was adopted to investigate the polymerization process of the nanocomposite particles and the mechanism of ion exchange in aqueous solution containing Cd²⁺． The morphology and structure of the as-prepared composite particles were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FT-IR). Combined with cyclic voltammetry (CV) and energy dispersive spectroscopy (EDS), the electrochemical behavior and the mechanism of ion exchange were also investigated in electrolytes of Cd^{2+ …}

A Comparative Study In Pretreatments Of Acid Chemical Wastewater By Electrochemical Oxidation And Ozonation, Han-Shui Liu, Su Yu, Shao-Ping Tong, Chun-An Ma

Journal of Electrochemistry

Under the condition of keeping certain acidity, the pretreatment efficiency of an acid chemical wastewater (pH 0.85) by electrochemical oxidation was compared with that by ozonation. The results showed that the electrochemical oxidation pretreatment could obtain a better result than the ozonation at pH 0.85. After the addition of 2 g·L^-1 NaCl and with the electrochemical oxidation pretreatment at 30 mA·cm^-2, the removal rate of chemical oxygen demand (CODCr) reached 43.4%, and the value of biochemical oxygen demand/chemical oxygen demand (BOD₅/COD_Cr) also increased from 0.034 to 0.14 in 20 minutes, indicating significantly improvement …

Preparation Of Benzoquinone From Phenol By Electrooxidation, Dong-Fang Niu, Cheng-Kai Yu, Xin-Sheng Zhang

Journal of Electrochemistry

The benzoquinone was prepared from phenol by electrooxidation in an H-type cell with cation exchange membrane, in which lead plates were used both as an anode and a cathode, while H₂SO₄ was used as a supporting electrolyte. The effects of current density, concentration of sulphuric acid, concentrations of benzoquinone in electrolyte and extractant on the yields and efficiencies of electrolysis were investigated. Under the optimized conditions of current density being 4 A·dm^-2, concentration of sulphuric acid 1 mol·L^-1, passed charge 3.2 A·h, the yield and current efficiency of benzoquinone could reach 68% and …

Experimental Design Methodology Applied To The Oxidation Of Quinolines In Aqueous Medium By Electro-Fenton Process, Souhaila Trabelsi Souissi, Nihal Oturan, Nizar Bellakhal, Mehmet A. Oturan

Journal of Electrochemistry

The degradation behavior of 8-hydroxyquinoleine sulfate (8-HQS), a model molecule of quinolines, was studied in an aqueous medium by electro-Fenton process using a carbon felt cathode and a platinum anode. The great oxidation ability of this process is due to a large production of hydroxyl radical (OH) by electrochemically induced Fenton’s reagent (H₂O₂, Fe²⁺). Hydroxyl radicals are very powerful oxidizing agents which react on organics up to complete mineralization. A factorial experimental design was used for determining the operating parameters on the degradation of 8-HQS in an aqueous medium. The results showed that the …

Optimization Of Polymer Separation By Gradient Polymer Elution Chromatography, Gideon R. Liem, Linda Nien-Hwa Wang

The Summer Undergraduate Research Fellowship (SURF) Symposium

High Performance Liquid Chromatography (HPLC) has been a versatile separation method for polymers for many years. Analysis of different polymers by HPLC is typically done by utilizing the differential solubility of the polymers by mixing a good solvent and an anti-solvent in various compositions. This method is called Gradient Polymer Elution Chromatography (GPEC). While GPEC has been used extensively, it commonly uses a linear gradient to separate components. Linear solvent gradients consume a lot of solvent and take a relatively long time (> 30 minutes) to complete. The goal of this study is to develop a step gradient from a …

Preparation Of Mesoporous Silica Supported Ruthenium Oxides And The Application And Kinetic Study In The Catalysis Of Water Oxidation, Yang Zhang

Open Access Dissertations

Photo-induced water splitting of water into H2 and O2 has been a major focus in the development of clean and renewable energy. The development of viable and efficient catalysts that facilitates O2 production remains the major challenge in the study of the corresponding half-reaction of water oxidation. There are plenty of metal oxides reported active in the catalysis of water oxidation. However, several important performance bench marks of those materials, such as the non-stoichiometric production of O2, slow reaction rate and/or low quantum efficiency, remain to be improved.

Ruthenium oxide (RuO2) has long been known as one of the most …

Development Of Quantitative Ft- Ir Methods For Analyzing The Cure Kinetics Of Epoxy Resins, Sang Ha Son

Open Access Dissertations

Epoxy thermosets are important engineering materials with applications in coating, adhesives, packaging and as structural components in a variety of advanced engineering products. The ultimate performance of polymer critically depends upon the details of the cure chemistry used to produce the thermoset. In order to better understand and monitor the cure chemistry, quantitative analysis of the FT-IR response has been developed for describing the epoxy-amine curing reaction as well as monitoring the hydrogen bonding that occurs in these systems The FT-IR analysis includes (i) quantitative deconvolution of complex peaks into individual spectral contributions, (ii) peak identification via DFT analysis and …

Elucidation Of Chiral Recognition Mechanisms Of Solutes By Amylose Tris[(S)-Alpha-Methylbenzylcarbamate] Sorbent, Hung-Wei Tsui

Open Access Dissertations

Enantioselective separations of chiral molecules are important in various chemical fields, such as pharmaceuticals and agrochemicals industries. Polysaccharide-based sorbents have been widely used in chiral liquid chromatography. The recognition mechanisms which determine their enantioselectivities are not completely understood.

In this dissertation, the chiral recognition mechanisms of a widely used commercial sorbent, amylose tris[(S)-alpha-methylbenzylcarbamate], for benzoin (B) enantiomers were first studied. The HPLC data for benzoin with pure n-hexane as the mobile phase have been obtained. The behavior of sorbent-solute-hexane systems can be interpreted by considering only sorbent solute two-component interactions. Infrared (IR) spectra showed evidence of substantial hydrogen bonding (H-bonding) …

The Effect Of Composition On The Linear And Nonlinear Mechanical Properties Of Particulate Filled Elastomers, Oluwaseyi Ogebule

Open Access Dissertations

Engineering elastomers are materials capable of undergoing large deformation upon load application and recovering upon load removal. From car tires to building vibration isolator systems, elastomers are the most versatile of engineering materials. The inclusion of particulate fillers into elastomers enhances their mechanical properties (modulus, tensile strength, toughness, tear resistance, etc) thereby extending their applicability to more demanding functions. The automotive, healthcare, construction, adhesives and consumer products are some of the many industries that produce finished goods containing elastomeric parts.

Despite the various concepts on reinforcement in filled elastomers, a complete understanding of their linear viscoelastic properties and the nonlinear …

Spectroscopic And Kinetic Study Of Copper-Exchanged Zeolites For The Selective Catalytic Reduction Of Nox With Ammonia, Shane Adam Bates

Open Access Dissertations

The recent application of metal-exchanged, small-pore zeolites for use in the selective catalytic reduction (SCR) of NO_x with ammonia NH₃ for automotive deNO_x applications has been a great stride in achieving emission standard goals. Copper-exchanged SSZ-13 (Cu-SSZ-13), the small-pore zeolite in this study, has been shown to be very hydrothermally stable and active under conditions presented in the exhaust of the lean-burn diesel engine. In this work, detailed studies were performed to identify many aspects of the active site(s) in Cu-SSZ-13 in order to learn about the standard SCR mechanism.

A series of seven Cu-SSZ-13 samples were …

Electrosynthesis Of Glycerol Carbonate From Co2 And Glycerol, Huan Wang, Mei-Xia Zhu, La-Xia Wu, Xiao-Ming Xu, Xue-Ru Zhao, Jia-Xing Lu

Journal of Electrochemistry

Glycerol carbonate was obtained from glycerol and carbon dioxide under room temperature and normal pressure by electrochemical method. The effects of synthesis conditions, such as cathode, charge, current density and temperature, on the reaction of glycerol and carbon dioxide have been investigated. The yields of 73% were produced by electrosynthesis of carbonate under the optimized condition, which is much higher than that by common catalysis method. The electrochemical behavior of the reaction system has been studied by cyclic voltammetry, through which the reaction process has been proposed.

Influence Of Pretreatment On Electrocatalytic Property For Methanol Oxidation Of Ptru/Wc, Xiao-Ling Lang, Mei-Qin Shi, Ye-Kun Jiang, Chun-An Ma

Journal of Electrochemistry

The surface of tungsten carbide (WC) was treated by potassium hydroxide (KOH) at different pH values for different time. The PtRu/WC composite was prepared by microwave-assisted polyol method. The phase structure of PtRu/WC composites were characterized by XRD. The electrocatalytic activity was tested by cyclic voltammetry and chronoamperometry. The results indicated that with different pH treatments WC became more readily supported on PtRu. When treating WC in KOH at pH = 14, PtRu exhibited the best degree of crystallinity on WC surface, leading to the highest electrocatalytic activity of PtRu/WC. Moreover, the optimized activity of PtRu/WC towards methanol oxidation was …

Synthesis And Electrochemical Properties Of Li(Ni0.5Co0.2Mn0.3)1-2xTiXNbXO2, Yong Tang, Qin-Lin Liao, Xiang-An Guo

Journal of Electrochemistry

The cathode-active materials of layered Li(Ni_0.5Co_0.2Mn_0.3)_1-2xTi_xNb_xO₂（x=0, 0.002, 0.005, 0.01, 0.02）composites were synthesized by the thermal treatment of the coprecipitated precursor at 900 ^oC in air. The effects of Ti-Nb co-dopants on the structural and electrochemical properties of Li(Ni_0.5Co_0.2Mn_0.3)O₂ were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical experiments. The results show that the small amounts of Ti-Nb co-dopants in Li(Ni_0.5Co_0.2Mn_0.3)O₂significantly decreased the degree of cation mixing in …

Research Progress Of Intermediate Layers In Ti-Based Oxide Anodes, Xiu-Li Song, Hui-Min Yang, Zhen-Hai Liang

Journal of Electrochemistry

Titanium (Ti)-based oxide anodes are excellent anode materials which have been applied widely in electrochemical fields all over the world. Adding intermediate layers in Ti-based oxide anodes can improve the conductivity, lengthen the lifetime and strengthen the stability between Ti base and metal oxides active layers of electrodes. This article reviews the research progress of intermediate layers in Ti-based oxide anodes. At the same time, current problems existed in the field of Ti-based oxide anodes are pointed out and future development trend in oxide electrode with intermediate layers is prospected.

Advanced Treatment Of Dyeing Wastewater For Reuse By Electrochemical Oxidation, Fei-Xiang Chen, Chu-Yin Yang, Ming-Ming Zhou, Jia-De Wang

Journal of Electrochemistry

In response to the characteristics of dye wastewater, the electrochemical oxidation of effluents from the biochemical process of dyeing wastewater was studied in the electrochemical reactor using PbO₂/Ti electrode as the anode and stainless steel plate as the cathode. The results revealed that the electrochemical oxidation could simultaneously remove the Chemical Oxygen Demand (COD), ammonia and chromaticity. At the residence time of 60 min and current density of 10 mA·cm^-2, the COD, ammonia, chromaticity, concentration of chloride ion and pH values could meet the water standards for “the reuse of urban recycling water-water quality standard for …

Voltage Reversal Behavior In Microbial-Anode Fuel Cells, En-Ren Zhang, Jun-Le Niu, Lei Liu, Guo-Wang Diao

Journal of Electrochemistry

Voltage reversal behavior was investigated in microbial-anode fuel cells (MFCs). Electricity-producing biofilms were developed on the surface of anodes in MFCs inoculated with mixed inoculum from activated sludge. MFC duplicates generally exhibited different performances with respect to the internal resistance, the voltage output and the discharging duration when operating in batch mode. Voltage reversal was observed to occur first in the MFC with lower performance when connecting MFCs in series. Analysis of electrode potentials indicated that the potentials of microbial anodes quickly shifted to more positive values when enhancing discharge current, resulting in voltage reversal in MFCs. Increasing temperature would …

Using Hydrolyzed Sludge Liquor As The Substrate Of Microbial Fuel Cell, Peng Liang, Chao Guo, Xia Huang

Journal of Electrochemistry

Hydrolyzed sludge liquor was used as the substrate of microbial fuel cell. When the thermal treatment time increased from 2 h to 96 h, pH varied little between 7.4 and 8.0. When the treatment time increased, the conductivity, COD and alkaline condition increased to 2.53 mS·cm^-1, 2520 mg·L^-1 and 800 mg·L^-1, respectively. Meanwhile, the power density increased to 25 W·m^-3. The COD removal increased firstly, then decreased, and finally reached the maximum of 47% at the hydrolyzed time of 6 h. The maximal coulombic efficiency was 71% when the treatment time was 4 …

Electrocatalytic Oxidation Degradation Kinetics Of Oxalic Acid In A Cylindrical Electrochemical Reactor With Ti/Iro2-Ta2O5 Anode, Jing Su, Hai-Bo Lin, Hong Xu, Wei-Min Huang, Ya-Peng He

Journal of Electrochemistry

The electrocatalytic oxidation degradation kinetics of oxalic acid in a cylindrical electrochemical reactor with Ti/IrO₂-Ta₂O₅  as an anode was studied. The relation between instantaneous current efficiency and organic concentration in bulk was established based on the two paths for direct electrochemical oxidations, and the theoretical model was verified by experiments. The experimental resultswere reasonably consistent with the established kinetic model. Furthermore, the competition between the two paths was explored with the modelparameter analysis.

Performance Of The Electro-Oxidation And Electro-Fenton Processes With A Bdd Anode For The Treatment Of Low Contents Of Pharmaceuticals In A Real Water Matrix, Sirs Ignasi, Antonio Garrido Jos, Brillas Enric

Journal of Electrochemistry

Here, we report the performance of electro-oxidation and electro-Fenton with a boron-doped diamond (BDD) anode for the treatment of single and multicomponent solutions containing small amounts of pharmaceutical residues (i.e., 1 mg·L^-1 paracetamol and/or 1 mg·L^-1 salicylic acid) spiked into a real water matrix at pH 3.0. Electro-oxidation was performed in a BDD/Pt cell, whereas electro-Fenton was carried out in a BDD/air-diffusion cell to electrogenerate H₂O₂ at the cathode, always operating at constant current density. It was found that the decay of both pharmaceuticals by electro-oxidation was more rapid in the real water matrix than …

Preparation And Characterization Of A Novel Composite Electrolyte Ceria-Sulfate For Intermediate Temperature Solid Oxide Fuel Cells, Ze Tong, Yi-Mei Yin, Jie-Wei Yin, Zi-Feng Ma

Journal of Electrochemistry

A novel composite electrolyte SDC-(Li/Na)₂SO₄ was prepared for intermediate temperature solid oxide fuel cells (ITSOFC). The phase structure and cross-sectional morphology were examined by XRD and SEM, respectively, and the ionic conductivity was investigated by AC impedance in a temperature range of 400 ^oC ~ 700 ^oC in air. It was found that the composite electrolyte was composed of two phases: crystal SDC and amorphous (Li/Na)₂SO₄. The conductivity of the composite electrolyte was significantly larger than that of SDC at intermediate temperatures (550 ^oC ~ 700 ^oC) and increased …

Influence Of Electrode Hydrophobicity On Performance Of Alkaline Polymer Electrolyte Fuel Cells, Li-Sheng Tan, Jing Pan, Yao Li, Lin Zhuang, Jun-Tao Lu

Journal of Electrochemistry

In the present work, we study the influence of the electrode hydrophobicity on the performance of alkaline polymer electrolyte fuel cells (APEFCs). QAPS or xQAPS is employed as the membrane and the ionomer, while PTFE is used as a hydrophobic additive in order to adjust the electrode hydrophobicity. We find that enhancing the hydrophobicity of anode can promote the performance of APEFCs, while a moderate hydrophobicity of cathode is required to achieve optimal performance. By using xQAPS as the electrolyte and adding some PTFE in the anode, a peak power density of 132 mW·cm^-2 can be obtained at a …