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2021

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Articles 331 - 360 of 672

Full-Text Articles in Chemical Engineering

Development Of An Integrated Salt Cartridge-Reverse Electrodialysis (Red) Device To Increase Electrolyte Concentrations Of Human Blood Flow To Power Biomedical Devices, Caroline Campbell May 2021

Development Of An Integrated Salt Cartridge-Reverse Electrodialysis (Red) Device To Increase Electrolyte Concentrations Of Human Blood Flow To Power Biomedical Devices, Caroline Campbell

Chemical Engineering Undergraduate Honors Theses

Emerging technologies in nanotechnology and biomedical sciences have led to an increase in biomedical implantable devices including cardiac pacemakers, artificial organs, drug pumps, and sensors. These devices require continuous stable and reliable power to operate, which creates the demand for the need to find a safe, reliable, and stable power source. A promising avenue for a power source for these devices is a miniaturized reverse electrodialysis (RED) biopower cell design that utilizes the salinity differences between bloodstreams that flow inside the human body. Initial results of the RED system demonstrate that higher gradient salinity differences between streams lead to a …


Garver Industrial Design Project: Designing A Full-Scale Reverse Osmosis Water Treatment Facility For The City Of Lawton, Oklahoma, Kayliana Warden, Marlando Collins, Sandrina Depaz, Reid Eakin, Reed Leasure, Vera Rodriguez May 2021

Garver Industrial Design Project: Designing A Full-Scale Reverse Osmosis Water Treatment Facility For The City Of Lawton, Oklahoma, Kayliana Warden, Marlando Collins, Sandrina Depaz, Reid Eakin, Reed Leasure, Vera Rodriguez

Chemical Engineering Undergraduate Honors Theses

A groundwater treatment facility was designed for Lawton, Oklahoma to address potential water scarcity due to drought conditions in southwest Oklahoma. The facility will produce five million gallons per day (MGD) of treated water. The plant will have the capacity of treating 4,085 gallons per minute of influent water at an 86% recovery. The water to be treated will come from the Arbuckle-Timbered Hills Aquifer. Studies have been conducted around the aquifer to identify the best well site locations.

A centralized treatment facility using reverse osmosis filtration as the main treatment technology has been designed. To prevent reverse osmosis membrane …


Predicting Henry's Law Constants Of Volatile Organic Compounds Present In Bourbon Using Molecular Simulations., Christopher A Abney May 2021

Predicting Henry's Law Constants Of Volatile Organic Compounds Present In Bourbon Using Molecular Simulations., Christopher A Abney

Electronic Theses and Dissertations

Henry’s Law describes the partitioning of molecules into liquid and gas phases at low concentrations. Henry’s Law, which is based upon a species-dependent constant and the gas phase partial pressure, is useful for predicting phase behavior of dilute solutes. However, Henry’s Law constants are difficult to measure experimentally or to predict using structure-property or thermodynamic models. Herein, molecular simulations were used to calculate Henry’s Law constants for 18 volatile organic compounds (VOCs) present in bourbon. The novel simulations analyzed solvation thermodynamics of small organic molecules in 120 proof ethanol. A fast-growth non-equilibrium free energy method was used in which the …


Analysis Of Fluid Flow In Redox Flow Batteries, Erfan Asadipour May 2021

Analysis Of Fluid Flow In Redox Flow Batteries, Erfan Asadipour

McKelvey School of Engineering Graduate Student Theses & Dissertations

Redox flow batteries (RFB) hold great potential for large-scale stationary energy storage. However, their low energy density compared to other energy storage systems must improve for feasibility. Electrolyte flow distribution affects current density distribution and providing a uniform current density distribution is one way to improve RFB performance. Additionally, reducing the power consumption of the electrolytes’ pump as a source of energy loss in RFB systems increases their efficiency. Investigating both subjects requires analysis of the fluid dynamics in RFB cells.

In this thesis, a novel, computationally cost-effective hydraulic-electrical analogous model (HEAM) was developed to study fluid dynamics by implementing …


Degradation Of Antibiotics In Aqueous Phase Using Pms Catalytic Decomposition With Zero-Valent Iron Nanoparticles Immobilized In Sba-15, Ahdee Bluma Zeidman May 2021

Degradation Of Antibiotics In Aqueous Phase Using Pms Catalytic Decomposition With Zero-Valent Iron Nanoparticles Immobilized In Sba-15, Ahdee Bluma Zeidman

UNLV Theses, Dissertations, Professional Papers, and Capstones

Zero-valent iron nanoparticles (nZVI) have been studied as an option for soil remediation and water treatment for many years. The capability of nZVI to produce oxidation/reduction processes, depending on the reaction conditions, has attracted great interest with their major drawback being reactivity loss through agglomeration. The loss in nZVI surface area has been reported to be prevented through immobilization onto a porous media (e.g., SBA-15, MCM-41, or zeolites). In this work, a mesoporous silica structure (SBA-15) is used as an nZVI supporting material to enhance its reactivity and promote peroxymonosulfate (PMS) catalytic decomposition for the degradation of antibiotics in aqueous …


Image Analysis Of Charged Bimodal Colloidal Systems In Microgravity., Adam J. Cecil May 2021

Image Analysis Of Charged Bimodal Colloidal Systems In Microgravity., Adam J. Cecil

Electronic Theses and Dissertations

Colloids are suspensions of two or more phases and have been topics of research for advanced, tunable materials for decades. Stabilization of colloids is typically attributed to thermodynamic mechanisms; however, recent studies have identified transport or entropic mechanisms that can potentially stabilize a thermodynamically unstable colloidal system. In this study, suspensions of silsesquioxane microparticles and zirconia nanoparticles were dispersed in a nitric acid solution and allowed to aggregate for 8-12 days in microgravity aboard the International Space Station. The suspensions were subsequently imaged periodically at 2.5x magnification. Due to the inadequacy of existing image analysis programs, the python package “Colloidspy” …


Annealing Of Encapsulated Heavy Metals From Brine Water Utilizing Microwave Enabled Sol-Gel Process, Adam Michael Flynn May 2021

Annealing Of Encapsulated Heavy Metals From Brine Water Utilizing Microwave Enabled Sol-Gel Process, Adam Michael Flynn

Electronic Theses and Dissertations

Various waste encapsulation strategies have been investigated to solidify and stabilize heavy metal wastewater for proper long-term storage. This work aims to enhance a method of novel sol-gel encapsulation of heavy metals from mock brine waters using tetramethyl orthosilicate with the addition of an annealing step at various temperatures in order to reduce leaching of metals from the silica monoliths when exposed to water. The metals tested for encapsulation and leaching were mercury (II) chloride, potassium dichromate, sodium selenite, boric acid, cadmium chloride, and copper (II) acetate. The annealing of the silica monoliths led to an increased degree of for …


Heavy Oil And Vapex Process: A Brief Review, Vijitha Mohan, Parthasakha Neogi, Baojun Bai May 2021

Heavy Oil And Vapex Process: A Brief Review, Vijitha Mohan, Parthasakha Neogi, Baojun Bai

Chemical and Biochemical Engineering Faculty Research & Creative Works

Heavy oil recovery requires either heat or solvent assistance to reduce its high viscosity first and then the less viscous oil can be recovered. Processes that use vapor assisted petroleum extraction (VAPEX) utilize vaporized solvent. Solvent vapors are introduced through a top injection well to induce viscosity reduction and the less viscous oil is collected at the bottom production well. It is noteworthy, that the solvent itself when recovered, can be seen as an integral part of oil. Exact molecular weight and chemistry of heavy oil is uncertain making analysis of thermodynamic properties difficult, however this is overcome by making …


In Vivo Analysis Of A Proprietary Glass-Based Adhesive For Sternal Fixation And Stabilization Using Rabbit And Sheep Models, Cina Mehrvar, Emily Deignan, Mark Hurtig, Gideon Cohen, Paul Zalzal, Oleg Safir, Adel Alhalawani, Marcello Papini, Mark R. Towler May 2021

In Vivo Analysis Of A Proprietary Glass-Based Adhesive For Sternal Fixation And Stabilization Using Rabbit And Sheep Models, Cina Mehrvar, Emily Deignan, Mark Hurtig, Gideon Cohen, Paul Zalzal, Oleg Safir, Adel Alhalawani, Marcello Papini, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Wire cerclage remains the standard method of care for sternal fixation, following median sternotomy, despite being beset with complications. An emerging treatment option has been to augment the wires with an adhesive. A patented ionomeric glass (mole fraction: SiO2:0.48, ZnO:0.36, CaO:0.12, SrO:0.04) has been used to formulate GPC+, a glass polyalkenoate cement (GPC), by mixing it with poly(acrylic) acid (PAA) and de-ionized water. In a human cadaver study, this material, when applied with wire cerclage, was able to significantly reduce sternal instability. However, the material has yet to be tested in pertinent animal models. Here, after a series …


Peptoid-Based Microsphere Coatings For Biomaterial Applications, Jesse Leland Roberts May 2021

Peptoid-Based Microsphere Coatings For Biomaterial Applications, Jesse Leland Roberts

Graduate Theses and Dissertations

Peptoids are peptidomimetic oligomers that predominantly harness similarities to peptides for biomimetic functionality. The incorporation of chiral, aromatic side chains in the peptoid sequence allows for the formation of distinct secondary structures and self-assembly into supramolecular assemblies, including microspheres. Peptoid microspheres can be coated onto substrates for potential use in biosensor technologies, tissue engineering platforms, and drug-delivery systems. They have the potential for use in biomedical applications due to their resistance to proteolytic degradation and low immunogenicity. This dissertation focuses on the physical characteristics and robustness of the peptoid microsphere coatings in various physiological conditions, along with their ability to …


Surface Modified Polypropylene Membranes For Treating Hydraulic Fracturing Produced Waters By Membrane Distillation, Tharaka Hawpe Gamage May 2021

Surface Modified Polypropylene Membranes For Treating Hydraulic Fracturing Produced Waters By Membrane Distillation, Tharaka Hawpe Gamage

Graduate Theses and Dissertations

Membrane distillation is an emerging technology for treating hydraulic fracturing flowback and produced waters. Suppression of membrane fouling by inorganic and polar and non-polar organic compounds is a challenge. Here polyhydroxyethyl methacrylate, polyacrylic acid, polvinylallyl imidazolium bromide and polyvinylhexyl imidazolium bromide chains have been grafted from the membrane surface. Fouling is initially due to adsorption of organic compounds followed by scale formation. When challenged with produced water, membranes modified with polvinylallyl imidazolium bromide chains provided the greatest resistance to fouling. For EC pretreated produced water and synthetic produced water that contained mainly inorganic species, the flux decline was much less.


Investigative Study Of Microalgal And Electrochemical Wastewater Treatment Systems And Modeling Of The Wafer-Enhanced Electrodeionization Using Supervised Learning, Humeyra Betul Ulusoy Erol May 2021

Investigative Study Of Microalgal And Electrochemical Wastewater Treatment Systems And Modeling Of The Wafer-Enhanced Electrodeionization Using Supervised Learning, Humeyra Betul Ulusoy Erol

Graduate Theses and Dissertations

Wastewater has a serious impact on environment and public health due to its high concentration of nutrients and toxic contaminants. Without proper treatment, excess nutrients discharged in wastewater can cause a damage to the ecosystem such as undesirable pH shifts, cyanotoxin production, and low dissolved oxygen concentrations.

Main objectives of this dissertation work were to investigate i) the biofuel potential of P. cruentum when grown in swine wastewater, ii) the influence of four most commonly used ion exchange resins on the system efficiency and selectivity for the removal of sodium, calcium, and magnesium ions, and iii) the modeling of wafer-enhanced …


Behavior Of Selective Oxygen Functional Groups Upon Hydrothermal Carbonization And Pyrolysis Of Biomass And Their Roles On Selective Applications, Nepu Saha May 2021

Behavior Of Selective Oxygen Functional Groups Upon Hydrothermal Carbonization And Pyrolysis Of Biomass And Their Roles On Selective Applications, Nepu Saha

Theses and Dissertations

Hydrothermal carbonization (HTC) is a thermochemical process where biomass is treated in water under high temperature and corresponding vapor pressure. During HTC, biomass undergoes a series of reactions including hydrolysis, decarboxylation, dehydration, aromatization, and polymerization. As a result, a solid product is produced from biomass after HTC process, which is widely known as hydrochar. Depending on the HTC process conditions, a wide-variety of oxygen-containing groups formed on hydrochar surfaces. Many of these groups could play critical roles in applications such as adsorption, and energy and gas storage, etc. However, not all functional groups are exposed on the surface due to …


Husky Hand: A Low-Cost Electro-Mechanical Prosthetic Arm For The Underprivileged, Adam Robert Apr 2021

Husky Hand: A Low-Cost Electro-Mechanical Prosthetic Arm For The Underprivileged, Adam Robert

Thinking Matters Symposium

A continuation of a low-cost prosthetic upper limb prototype design which was investigated in EGN 301. The prosthetic is specifically designed for the needs and requirements of under privileged individuals in the Dominican Republic with upper limb amputations. The project focuses on the creation of an open-source computer aided prosthetic hand/arm model. The design allows consumer-grade fused filament fabrication (FFF) 3-D printers to be used. The improved design allows for the integration of the PQ-12 linear actuator for grasp and finger control. This simplifies the assembly, while, also reducing the size and mass of the whole unit. Producing a low-cost …


Design, Analysis, And Optimization Of A Process To Produce Dimethyl Ether From Methanol, Thomas Mathwig Apr 2021

Design, Analysis, And Optimization Of A Process To Produce Dimethyl Ether From Methanol, Thomas Mathwig

Honors Theses

The company that the engineering team works for is facing a contract loss with one of its customers of methanol. To avoid economic losses, a process has been proposed for converting the unused methanol to dimethyl ether (DME) through a dehydration reaction. After a preliminary simulation of the base case and optimization of the distillation column, an Equivalent Annual Operating Cost (EAOC) of $140,000 was calculated for the column. The EAOC was the sum of the annualized capital investment and the annual operating cost. Determining the process to be worth pursuing, a Toller was brought in to provide rental equipment …


Co2-Wettability Reversal Of Cap-Rock By Alumina Nanofluid: Implications For Co2 Geo-Storage, Muhammad Ali, Adnan Aftab, Faisal Ur Rahman Awan, Hamed Akhondzadeh, Alireza Keshavarz, Ali Saeedi, Stefan Iglauer, Mohammad Sarmadivaleh Apr 2021

Co2-Wettability Reversal Of Cap-Rock By Alumina Nanofluid: Implications For Co2 Geo-Storage, Muhammad Ali, Adnan Aftab, Faisal Ur Rahman Awan, Hamed Akhondzadeh, Alireza Keshavarz, Ali Saeedi, Stefan Iglauer, Mohammad Sarmadivaleh

Research outputs 2014 to 2021

The usage of nanofluids is vast in different applications of nano-energy. These minute nanoparticles can be used to alter the hydrophobicity into hydrophilicity for CO2-brine-mineral systems in the presence of organic acids. Nonetheless, the literature lacks the information for the behavior of nanoparticles and its associated concentrations in the presence of organic acids at the reservoir (high temperature and high pressure) conditions. In this study, we have investigated that how different alkyl chain organic acids impact the wettability of mica muscovite for different ageing times (7 days and one year) and how this impact can be reversed by nanofluid priming …


Recovery Of Degraded Lithium Ion Cathode Particles, James Kirtley Apr 2021

Recovery Of Degraded Lithium Ion Cathode Particles, James Kirtley

Undergraduate Research Conference at Missouri S&T

This project focuses on recovering the cathode materials of lithium ion batteries through atomic layer deposition (ALD) thin film coating. In industry, when a cathode material for a lithium ion battery are stored, it reacts with CO2 and moisture in the air creating Li2CO3 and LiOH on the particle surface. The harmful substances on the surfaces have a negative impact on battery performance and battery life. In this study, we found that when Li2Ni0.8Mn0.1Co0.1 (Ni-Rich NMC) is exposed to a high amount of moisture it degrades and the performance is reduced. For example, the discharge capacity of Degraded Ni-Rich NMC …


Effects Of Sleep Deprivation On Learning In Fruit Flies, Natalie Gardner Apr 2021

Effects Of Sleep Deprivation On Learning In Fruit Flies, Natalie Gardner

Undergraduate Research Conference at Missouri S&T

The fruit fly Drosophila Melanogaster is an optimal research specimen when observing the effects of sleep deprivation on spatial learning. A fly's sleep can be tracked using locomotion while it is undisturbed and while it undergoes sleep deprivation. To measure a fly's visuospatial awareness, a region at a comfortable 24 degrees Celsius, among the rest of the arena yielding an uncomfortable temperature ranging from 36-37 degrees Celsius, is fit with a specific visual cue that the fly is able to identify. This region, along with it's visual cue, is rotated around the arena every 3 minutes, and the amount of …


Pd-Based Electrocatalysts For Oxygen Reduction And Ethanol Oxidation Reactions: Some Recent Insights Into Structures And Mechanisms, Zhi-Peng Wu, Chuan-Jian Zhong Apr 2021

Pd-Based Electrocatalysts For Oxygen Reduction And Ethanol Oxidation Reactions: Some Recent Insights Into Structures And Mechanisms, Zhi-Peng Wu, Chuan-Jian Zhong

Journal of Electrochemistry

The development of efficient electrocatalysts for applications in fuel cells, including proton-exchange membrane fuel cell (PEMFC) and direct ethanol fuel cell (DEFC), has attracted extensive research attention in recent years. Oxygen reduction reaction and ethanol oxidation reaction are two of the key reactions where the design of active, stable and low-cost electrocatalysts is critical for the mass commercializations of PEMFCs and DEFCs. This challenge stems largely from the limited understanding of the catalyst structures and reaction mechanisms. Progress has been made in investigations of electrocatalysts derived from Pd-based alloy nanomaterials both experimentally and computationally. We highlight herein some of the …


Theoretical Studies Of Metal-N-C For Oxygen Reduction And Hydrogen Evolution Reactions In Acid And Alkaline Solutions, Xue-Ping Qin, Shang-Qian Zhu, Lu-Lu Zhang, Shu-Hui Sun, Min-Hua Shao Apr 2021

Theoretical Studies Of Metal-N-C For Oxygen Reduction And Hydrogen Evolution Reactions In Acid And Alkaline Solutions, Xue-Ping Qin, Shang-Qian Zhu, Lu-Lu Zhang, Shu-Hui Sun, Min-Hua Shao

Journal of Electrochemistry

Single atom catalysts (SAC) have been regarded as the promising alternatives to platinum group metals due to their low costs and potentially high catalytic activities in various electrocatalytic reactions. The atomic mechanism understanding of activity discrepancy among different metal and nitrogen co-doped carbon-based catalysts is still lacking. Here, non-precious metal and nitrogen co-doped carbons (Me-N-C, Me = Fe and Co) as the model catalysts are investigated by combining experimental and theoretical studies to explore the catalytic activities and corresponding reaction mechanisms toward oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) at universal pHs. Atomic theoretical simulations suggest that Fe-N-C …


Oxygen-Exposure Induced Rapid Oxidation Of Spiro-Ometad In Cspbibr2 Perovskite Solar Cells, Wei-Guo Wang, Tian Bai, Gao-Fei Xue, Mei-Dan Ye Apr 2021

Oxygen-Exposure Induced Rapid Oxidation Of Spiro-Ometad In Cspbibr2 Perovskite Solar Cells, Wei-Guo Wang, Tian Bai, Gao-Fei Xue, Mei-Dan Ye

Journal of Electrochemistry

2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (Spiro-OMeTAD) is the most widely used hole transport material in perovskite solar cells (PSCs). However, its oxidation in the air takes a long time and results in the attack of perovskite by water. In this regard, we performed the oxidation process of Spiro-OMeTAD in oxygen, where perovskite can be protected from water, guaranteeing the integrity of perovskite. It was demonstrated that the champion Spiro-OMeTAD based CsPbIBr2 PSCs after oxygen oxidation achieved a 7.19% power conversion efficiency (PCE), showing a higher PCE than 6.29% of the champion device oxidized in air. A series of electrochemical characterization methods were applied …


Application Of Atomically Precise Metal Nanoclusters In Electrocatalysis, Zhi-Hua Zhuang, Wei Chen Apr 2021

Application Of Atomically Precise Metal Nanoclusters In Electrocatalysis, Zhi-Hua Zhuang, Wei Chen

Journal of Electrochemistry

Metal nanoclusters (M NCs) consist of only several to a few hundred of metal atoms and possess core sizes less than 2 nm. Owing to the quantum size effect, the electronic states of M NCs evolve to discrete levels similar to the molecule energy gaps, other than a continuous density of states to produce plasmon characteristic of bulk metal nanoparticles (M NPs). In comparison with the conventional M NPs, M NCs exhibit dramatically unique electronic and optical properties, such as molecule-like energy gaps, strong photoluminescence and high catalytic properties, which make them promising for potential application in numerous fields, such …


Detection And Aggregation Of Listeria Monocytogenes Using Polyclonal Antibody Gold-Coated Magnetic Nanoshells Surface-Enhanced Raman Spectroscopy Substrates, Robert T. Busch, Farzia Karim, Yvonne Sun, H. Christopher Fry, Yuzi Liu, Chenglong Zhao, Erick S. Vasquez Apr 2021

Detection And Aggregation Of Listeria Monocytogenes Using Polyclonal Antibody Gold-Coated Magnetic Nanoshells Surface-Enhanced Raman Spectroscopy Substrates, Robert T. Busch, Farzia Karim, Yvonne Sun, H. Christopher Fry, Yuzi Liu, Chenglong Zhao, Erick S. Vasquez

Chemical and Materials Engineering Faculty Publications

Magnetic nanoshells with tailored surface chemistry can enhance bacterial detection and separation technologies. This work demonstrated a simple technique to detect, capture, and aggregate bacteria with the aid of end-functionalized polyclonal antibody gold-coated magnetic nanoshells (pAb-Lis-AuMNs) as surface-enhanced Raman spectroscopy (SERS) probes. Listeria monocytogenes were used as the pathogenic bacteria and the pAb-Lis-AuMNs, 300 nm diameter, were used as probes allowing facile magnetic separation and aggregation. An optimized covalent bioconjugation procedure between the magnetic nanoshells and the polyclonal antibody was performed at pH six via a carbodiimide crosslinking reaction. Spectroscopic and morphological characterization techniques confirmed the fabrication of stable pAb-Lis-AuMNs. …


Editors’ Choice-Examining Performance And Durability Of Anion Exchange Membrane Fuel Cells With Novel Spirocyclic Anion Exchange Membranes, Ami C. Yang-Neyerlin, Samantha Medina, Kelly M. Meek, Derek J. Strasser, Cheng He, Daniel M. Knauss, Mustain E William, Svitlana Pylypenko, Bryan S. Pivovar Apr 2021

Editors’ Choice-Examining Performance And Durability Of Anion Exchange Membrane Fuel Cells With Novel Spirocyclic Anion Exchange Membranes, Ami C. Yang-Neyerlin, Samantha Medina, Kelly M. Meek, Derek J. Strasser, Cheng He, Daniel M. Knauss, Mustain E William, Svitlana Pylypenko, Bryan S. Pivovar

Faculty Publications

A series of spirocyclic copolymer membranes with varying ion exchange capacities (IECs) were investigated to probe the impact of polymer properties on in situ fuel cell performance and stability. In-situ electrochemical tests and post-mortem electron microscopy analysis of cross-sectioned membrane electrode assemblies (MEAs) have been combined with voltage loss breakdown analysis to evaluate the performance and degradation of different MEAs, and to probe the catalyst morphology and electrode structure at different stages of operation. Voltage loss breakdown results show that membrane degradation and kinetic losses played only a minor role in observed performance degradation and that performance losses were primarily …


Sorption-Spectrometric Determination Of Nickel By Monoammonium Salt Of Glycirrizic Acid, Ugilay Abdurakhmanova, Khabibjon Kushiev Apr 2021

Sorption-Spectrometric Determination Of Nickel By Monoammonium Salt Of Glycirrizic Acid, Ugilay Abdurakhmanova, Khabibjon Kushiev

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work is to develop a sensitive, selective and rapid method for the determination of nickel ions using the monoammonium salt of glycyrrhizic acid as an analytical reagent. There obtained IR spectra of the nickel diglycyrrhizinate complex. A simple and express spectral method for determination of the nickel ion is presented. The optimal conditions for the determination of the nickel ion are found. Under optimal conditions, a gradual graph was drawn up, which is linear in the concentration range for nickel of 20.0–40.0 μg/25 ml, the composition of the complex of nickel with the monoammonium salt …


The Role Of The 2,7-Dinitroso-1,8-Dihydroxynaphthalene-3,6-Disulfonic Acid Reagent In Determining The Thorium Ion (Iv), Nigora Qutlimurotova, Salohiddin Mahmadoliyev, Khabibullo Todjimukhamedov Apr 2021

The Role Of The 2,7-Dinitroso-1,8-Dihydroxynaphthalene-3,6-Disulfonic Acid Reagent In Determining The Thorium Ion (Iv), Nigora Qutlimurotova, Salohiddin Mahmadoliyev, Khabibullo Todjimukhamedov

CHEMISTRY AND CHEMICAL ENGINEERING

The aim is to develop a method for the amperometric determination of thorium (IV) ion with 2,7-dinitroso-1,8-dihydroxynaphthalene-3,6-disulfoxyl reagent. Methods of amperometric determination of thorium by solution of 2,7-dinitrozo-1,8-dihydroxynaphthalene-3,6-disulfonic acid on different acid-base properties of background electrolytes and buffer mixtures are considered. The half-wave potential of new reagent was found by logarithmic analysis equal 0.72 V at pH 2.82, which once again indicates on the irreversibility of the process of electrooxidation of the studied organic reagent in used acid-base medias. The conditions for amperometric titration of thorium are optimized, and the influence of outside accompanying metals on the shape of curves …


Synthesis Of Some N-Oxides Of Pyridylacethylene Amines Based On 2-Methyl-5-Ethynylpyridine, Abduvakhab Ikramov, Odiljon Ziyadullayev, Adkham Khamidjanov, Shavkat Bojariev, Davron Khandamov Apr 2021

Synthesis Of Some N-Oxides Of Pyridylacethylene Amines Based On 2-Methyl-5-Ethynylpyridine, Abduvakhab Ikramov, Odiljon Ziyadullayev, Adkham Khamidjanov, Shavkat Bojariev, Davron Khandamov

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work is to study the reaction of 2-methyl-5-ethynylpyridine N-oxide with some aliphatic and aromatic amines to obtain N-oxides of pyridylacetylenic amines. 2-Methyl-5-ethylpyridine converted to 2-methyl-5-vinylpyridine by dehydrogenation, and 2-methyl-5-ethynylpyridine obtained by bromination and dehydrobromination. 2-methyl-5-ethynylpyridine N-oxide synthesized by oxidation of 2-methyl-5-ethynylpyridine with perhydrol in acetic anhydride. The synthesis of N-oxides of pyridylacetylenic amines by the Mannich reaction carried out. The effect of the solvents: methanol, ethanol and n-dioxane, the catalyst, and the reaction time on the yield of the final product studied. The structure and composition of the synthesized PAA N-oxides were established using IR and …


The Role Of Hydrogen Bonds In Diluted Ethanol Solutions Of Cyclohexane And Dimethylformamide, Dilbar Bozorova, Shukur Gofurov, Mavlonbek Ziyayev, Dildora Mirtojiyeva, Odina Ismanova, Oksana Ismoilova Apr 2021

The Role Of Hydrogen Bonds In Diluted Ethanol Solutions Of Cyclohexane And Dimethylformamide, Dilbar Bozorova, Shukur Gofurov, Mavlonbek Ziyayev, Dildora Mirtojiyeva, Odina Ismanova, Oksana Ismoilova

CHEMISTRY AND CHEMICAL ENGINEERING

The refractometric method and Fourier transform infrared spectroscopy were used to determine the optical features of the concentration characteristics of diluted ethanol solutions of cyclohexane and dimethylformamide. It was found for the first time that at some concentrations the hydrogen bond is stronger than for a pure ethanol solution. The first maximum of the excess refractive index of solutions is formed at a concentration of 0.02 mole fraction of cyclohexane and dimethylformamide, which is in good correlation with IR spectroscopy, indicating the largest number of formed hydrogen bonds.


Polymers And Solvents Used In Membrane Fabrication: A Review Focusing On Sustainable Membrane Development, Xiaobo Dong, David Lu, Tequila A. L. Harris, Isabel C. Escobar Apr 2021

Polymers And Solvents Used In Membrane Fabrication: A Review Focusing On Sustainable Membrane Development, Xiaobo Dong, David Lu, Tequila A. L. Harris, Isabel C. Escobar

Chemical and Materials Engineering Faculty Publications

(1) Different methods have been applied to fabricate polymeric membranes with non-solvent induced phase separation (NIPS) being one of the mostly widely used. In NIPS, a solvent or solvent blend is required to dissolve a polymer or polymer blend. N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF) and other petroleum-derived solvents are commonly used to dissolve some petroleum-based polymers. However, these components may have negative impacts on the environment and human health. Therefore, using greener and less toxic components is of great interest for increasing membrane fabrication sustainability. The chemical structure of membranes is not affected by the use of different solvents, …


Peptoid Microsphere Coatings To Improve Performance In Sandwich Elisa Microarrays, Jesse L. Roberts, German R. Perez Bakovic, Shannon L. Servoss Apr 2021

Peptoid Microsphere Coatings To Improve Performance In Sandwich Elisa Microarrays, Jesse L. Roberts, German R. Perez Bakovic, Shannon L. Servoss

Chemical Engineering Faculty Publications and Presentations

Enzyme-linked immunosorbent assay (ELISA) microarray performance is limited by low assay sensitivity and dynamic range. Increasing the surface area for reagent binding can help to improve performance, but standard techniques such as roughening the surface or adding a polymer coating lead to increased non-specific fluorescence and do not have reproducibly improved performance. Another approach to increase surface area is adding a microsphere coating on the surface. Poly-N-substituted glycine (peptoid) microspheres are ideal for this application due to low immunogenicity, protease-resistance, and biocompatibility. Peptoids are polymers with a backbone similar to peptides, but with the side chains appended to nitrogen rather …