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Full-Text Articles in Engineering
Mass Advection–Diffusion In Creeping Flow Through An Orifice Plate: A Model For Nanoporous Atomically Thin Membranes, Harpreet Atwal, Anika Wong, Michael Boutilier
Mass Advection–Diffusion In Creeping Flow Through An Orifice Plate: A Model For Nanoporous Atomically Thin Membranes, Harpreet Atwal, Anika Wong, Michael Boutilier
Chemical and Biochemical Engineering Publications
Continuum transport equations are commonly applied to nanopores in atomically thin membranes for simple modeling. Although these equations do not apply for nanopores approaching the fluid or solute molecule size, they can be reasonably accurate for larger nanopores. Relatively large graphene nanopores have applications in small particle filtration and appear as unwanted defects in large-area membranes. Solute transport rates through these nanopores determine the rejection performance of the membrane. Atomically thin membranes commonly operate in a regime where advection and diffusion both contribute appreciably to transport. Solute mass transfer rates through larger nanopores have previously been modeled by adding continuum …
Mechanisms Of Asymmetric Membrane Formation In Nonsolvent-Induced Phase Separation, Jan Ulric Garcia, Tatsuhiro Iwama, Eva Y. Chan, Douglas R. Tree, Kris T. Delaney, Glenn H. Fredrickson
Mechanisms Of Asymmetric Membrane Formation In Nonsolvent-Induced Phase Separation, Jan Ulric Garcia, Tatsuhiro Iwama, Eva Y. Chan, Douglas R. Tree, Kris T. Delaney, Glenn H. Fredrickson
Faculty Publications
We report the first simulations of nonsolvent-induced phase separation (NIPS) that predict membrane microstructures with graded asymmetric pore size distribution. In NIPS, a polymer solution film is immersed in a nonsolvent bath, enriching the film in nonsolvent, and leading to phase separation that forms a solid polymer-rich membrane matrix and polymer-poor membrane pores. We demonstrate how mass-transfer-induced spinodal decomposition, thermal fluctuations, and glass-transition dynamics—implemented with mobility contrast between the polymer-rich and polymer-poor phases—are essential to the formation of asymmetric membrane microstructures. Specifically, we show that the competition between the propagation of the phase-separation and glass-transition fronts determines the degree of …
Self-Cleaning Nanocomposite Membranes With Phosphorene-Based Pore Fillers For Water Treatment, Joyner Eke, Katherine Elder, Isabel Escobar
Self-Cleaning Nanocomposite Membranes With Phosphorene-Based Pore Fillers For Water Treatment, Joyner Eke, Katherine Elder, Isabel Escobar
Chemical and Materials Engineering Faculty Publications
Phosphorene is a two-dimensional material exfoliated from bulk phosphorus and it possesses a band gap. Specifically, relevant to the field of membrane science, the band gap of phosphorene provides it with potential photocatalytic properties, which could be explored in making reactive membranes that can self-clean. The goal of this study was to develop an innovative and robust membrane that is able to control and reverse fouling with minimal changes in membrane performance. To this end, for the first time, membranes have been embedded with phosphorene. Membrane modification was verified by the presence of phosphorus on membranes, along with changes in …
Performance Of Nanoporous Carbon Membrane For Hydrogen Recovery, Abdulrahman A. Al-Rabiah, Abdelhamid M. Ajbar, Moustafa A. Soliman, Omar Y. Abdelaziz
Performance Of Nanoporous Carbon Membrane For Hydrogen Recovery, Abdulrahman A. Al-Rabiah, Abdelhamid M. Ajbar, Moustafa A. Soliman, Omar Y. Abdelaziz
Chemical Engineering
The aim of this work is to study the performance of nanoporous carbon membrane for hydrogen recovery from off-gas streams. The study is based on a rigorous mathematical model which can predict the performance of nanoporous selective surface flow (SSF) carbon membrane. Basically, the developed model is based on two transport mechanisms: the dusty gas flow through porous media and the surface adsorption-diffusion. The model was employed to simulate the hydrogen recovery from off-gas stream using SSF carbon membrane at different operating conditions. The separation performance of hydrogen-hydrocarbon mixture by nanoporous carbon membrane was evaluated and described. A comparison between …
Reaction Kinetics Of Ethane Partial Oxidation To Acetic Acid, Sulaiman Al-Mayman, Moustafa A. Soliman, Abdulrhman S. Al-Awadi, Yousef S. Al-Zeghayer
Reaction Kinetics Of Ethane Partial Oxidation To Acetic Acid, Sulaiman Al-Mayman, Moustafa A. Soliman, Abdulrhman S. Al-Awadi, Yousef S. Al-Zeghayer
Chemical Engineering
The partial oxidation of ethane to ethylene and acetic acid on supported MoVNbPd/TiO2 (P25 of Degussa) has been investigated. Pd was added in a nano-metallic form. The catalyst composition was also different from similar studied catalysts. This results in a better selectivity towards acetic acid formation. The reaction was carried out in a tubular reactor at temperature range 225–275 °C, total pressure range 0–200 psig and oxygen percentage in the feed gas of 10–40%. The feed gas contains ethane and oxygen. In this work, we develop a kinetic model for the reaction for the developed catalyst. In this model, we …
Green Synthesis Nanocomposite Membranes, Dibakar Bhattacharyya, Vasile Smuleac, Rajender S. Varma, Subhas K. Sikdar
Green Synthesis Nanocomposite Membranes, Dibakar Bhattacharyya, Vasile Smuleac, Rajender S. Varma, Subhas K. Sikdar
Chemical and Materials Engineering Faculty Patents
A nanocomposite membrane includes a macroporous polymer membrane having a plurality of pores. A plurality of metal nanoparticles are synthesized and immobilized within those plurality of pores. The nanoparticles are reduced and capped with a green reducing and capping agent such as green tea extract.
Chemical Processing Cell With Nanostructured Membranes, Dibakar Bhattacharyya, Scott R. Lewis, Saurav Datta
Chemical Processing Cell With Nanostructured Membranes, Dibakar Bhattacharyya, Scott R. Lewis, Saurav Datta
Chemical and Materials Engineering Faculty Patents
A chemical processing cell includes an upstream membrane and a downstream membrane. The upstream membrane generates a first reaction product. The downstream membrane converts the first reaction product to a second reaction product.
Membrane Compatibility With Switchable Polarity Draw Solutions For Use In Forward Osmosis Applications, Benjamin Joseph Coscia
Membrane Compatibility With Switchable Polarity Draw Solutions For Use In Forward Osmosis Applications, Benjamin Joseph Coscia
Honors Scholar Theses
Water scarcity is problem being faced worldwide and present in every continent. Close to one-fifth of the world’s population has difficulty acquiring safe water, and the problem is worsening as populations continue to grow in poorer countries. As the availability of unimpaired freshwater sources dwindle, water sources, such as the oceans and saline ground waters, must be tapped. However, desalination technologies are very expensive due to a high energy requirement. Forward osmosis (FO) is a process which may be able to replace or become integrated with existing desalination technologies like reverse osmosis. FO relies on an osmotic agent, or draw …
Co2-Selective Membranes Containing Amino Groups, W.S. Winston Ho
Co2-Selective Membranes Containing Amino Groups, W.S. Winston Ho
Chemical and Materials Engineering Faculty Patents
Novel compositions suitable for fabrication of CO2-selective membranes are disclosed. In one aspect, the present invention is directed to compositions comprising polyimide/polyamine blends and copolymers, and to compositions comprising interfacially polymerized polyamides. In another aspect this invention is directed to novel CO2-selective membranes comprising such polyimide/polyamine blends and copolymers, and to novel CO2-selective membranes comprising interfacially polymerized polyamides. In yet another aspect, the present invention is directed to a novel water-gas-shift (WGS) reactor comprising the novel CO2-selective membranes. Advantageously, the use of the novel CO2-selective membrane allows alteration of the …
Water Transport In Polymer Electrolyte Membrane Electrolyzers Used To Recycle Anhydrous Hcl: I. Characterization Of Diffusion And Electro-Osmotic Drag, Sathya Motupally, Aaron J. Becker, John W. Weidner
Water Transport In Polymer Electrolyte Membrane Electrolyzers Used To Recycle Anhydrous Hcl: I. Characterization Of Diffusion And Electro-Osmotic Drag, Sathya Motupally, Aaron J. Becker, John W. Weidner
Faculty Publications
In this paper, diffusion and electro-osmotic drag of water across Nafion® membranes in the presence of HCl are characterized. For all the measurements, one side of the Nafion membrane was in contact with liquid water and the other side with gaseous anhydrous HCl. To characterize diffusion of water, the open-circuit flux of water across a catalyst-coated Nafion 115 membrane was measured as a function of HCl flow rate and temperature at a constant cell pressure of 1 atm. Due to the nature of varying driving force for diffusion as a function of HCl flow rate, the experimental data was analyzed …
Oxygen Diffusion Coefficient And Solubility In A New Proton Exchange Membrane, Andrew T. Haug, Ralph E. White
Oxygen Diffusion Coefficient And Solubility In A New Proton Exchange Membrane, Andrew T. Haug, Ralph E. White
Faculty Publications
No abstract provided.
The Effects Of Organic Compounds On Inhibition Of Hydrogen Permeation Through A Mild Steel Membrane, H. A. Duarte, D. M. See, Branko N. Popov, Ralph E. White
The Effects Of Organic Compounds On Inhibition Of Hydrogen Permeation Through A Mild Steel Membrane, H. A. Duarte, D. M. See, Branko N. Popov, Ralph E. White
Faculty Publications
The effectiveness of 5-(4-pyridyl)-2,7-nonadiene, and 1 phenyl-2-propyn-ol (PP) on inhibition of the hydrogen evolution reaction on a 1010 steel membrane and on the degree of hydrogen ingress into the membrane was determined. Hydrogen evolution rates and permeation currents were monitored as a function of time at different applied potentials. In the presence of 0.5 g/liter PP in the electrolyte, the hydrogen discharge and permeation current density were inhibited by 98 and 95%, respectively.
Mathematical Modeling Of Proton‐Exchange‐Membrane Fuel‐Cell Stacks, Dhanwa Thirumalai, Ralph E. White
Mathematical Modeling Of Proton‐Exchange‐Membrane Fuel‐Cell Stacks, Dhanwa Thirumalai, Ralph E. White
Faculty Publications
No abstract provided.
The Effects Of Organic Compounds On Inhibition Of Hydrogen Permeation Through A Mild Steel Membrane, H. A. Duarte, D. M. See, Branko Popov, Ralph E. White
The Effects Of Organic Compounds On Inhibition Of Hydrogen Permeation Through A Mild Steel Membrane, H. A. Duarte, D. M. See, Branko Popov, Ralph E. White
Faculty Publications
No abstract provided.
The Effects Of Multiple Electroplated Zinc Layers On The Inhibition Of Hydrogen Permeation Through An Iron Membrane, D. H. Coleman, G. Zheng, Branko N. Popov, Ralph E. White
The Effects Of Multiple Electroplated Zinc Layers On The Inhibition Of Hydrogen Permeation Through An Iron Membrane, D. H. Coleman, G. Zheng, Branko N. Popov, Ralph E. White
Faculty Publications
The Devanathan-Stachurski permeation technique was used to investigate the rate of hydrogen permeation through an iron membrane with consecutively electroplated zinc layers. Hydrogen evolution rates and hydrogen permeation rates were followed as functions of time at different applied potentials. Hydrogen evolution and permeation decreased with each successive zinc layer until finally reaching an average decrease of 93 and 96%, respectively, as compared with bare iron. Hydrogen surface coverage, exchange current density, absorption-adsorption reaction constant, and hydrogen recombination constant were estimated on bare iron and on zinc-plated iron. It was found that the decrease in the permeation rate of hydrogen through …
Hydrogen-Atom Direct-Entry Mechanism Into Metal Membranes, G. Zheng, Branko N. Popov, Ralph E. White
Hydrogen-Atom Direct-Entry Mechanism Into Metal Membranes, G. Zheng, Branko N. Popov, Ralph E. White
Faculty Publications
The hydrogen-atom direct-entry mechanism is used to explain why the steady-state hydrogen permeation current density through a metal membrane is directly proportional to the cathodic current density, ic, and is independent of the membrane thickness when ic is small.
Surface Treatment For Mitigation Of Hydrogen Absorption And Penetration Into Aisi 4340 Steel, G. Zheng, Branko N. Popov, Ralph E. White
Surface Treatment For Mitigation Of Hydrogen Absorption And Penetration Into Aisi 4340 Steel, G. Zheng, Branko N. Popov, Ralph E. White
Faculty Publications
The effectiveness of underpotential deposition of Pb onto a membrane made of AISI 4340 steel on the reduction of the hydrogen evolution reaction on the membrane and the degree of hydrogen ingress into the membrane was determined. In the presence of a monolayer coverage of Pb on the membrane surface, the hydrogen evolution currents were reduced by a factor of two compared with the values obtained on bare steel, and the steady-state hydrogen permeation flux through the steel membranes was reduced by 71%.
Hydrogen Diffusion, Solubility, And Water Uptake In Dow's Short-Side-Chain Perfluorocarbon Membranes, Yu-Min Tsou, M. C. Kimble, Ralph E. White
Hydrogen Diffusion, Solubility, And Water Uptake In Dow's Short-Side-Chain Perfluorocarbon Membranes, Yu-Min Tsou, M. C. Kimble, Ralph E. White
Faculty Publications
Hydrogen gas diffusion coefficients and solubilities as well as water uptake values are reported for Dow's short-side-chain perfluoro-sulfonic and -carboxylic membranes of different equivalent weight (EW). The diffusion coefficients and solubilities were determined with an electrochemical test cell. Hydrogen solubility decreases with increasing EW in the lower EW range and tends to level off at higher EWs for both types of membranes. Both hydrogen solubility and diffusion coefficients of a sulfonic membrane with EW higher than 800 are higher than the corresponding values of a carboxylic membrane of similar EW. An unusual maximum is observed in the diffusion coefficient-EW plot …
Three-Dimensional Current Distributions In A Bipolar, Chlor-Alkali Membrane Cell, Ralph E. White, F. Jagush, H. S. Burney
Three-Dimensional Current Distributions In A Bipolar, Chlor-Alkali Membrane Cell, Ralph E. White, F. Jagush, H. S. Burney
Faculty Publications
The current distributions in a stack of bipolar, membrane
chlor-alkali cells are important design considerations
(1). The degree of nonuniformity of the current distribution
is important to know because highly nonuniform
current distributions could cause, among other things, severe
damage to the membrane in a cell stack (2).
Estimation Of The Diffusion Coefficient And Solubility For A Gas Diffusing Through A Membrane, Michael C. Kimble, Ralph E. White, Yu-Min Tsou, R. Neal Beaver
Estimation Of The Diffusion Coefficient And Solubility For A Gas Diffusing Through A Membrane, Michael C. Kimble, Ralph E. White, Yu-Min Tsou, R. Neal Beaver
Faculty Publications
Analysis of the data obtained by the electrochemical monitoring technique for diffusion of a gas through a membrane is considered. It is shown that combining a numerical method with a nonlinear parameter estimation technique provides a means to determine values for the diffusion coefficient and the solubility of the diffusing gas. It is shown that better accuracy can be obtained for the diffusion coefficient and solubility of this gas by using the method presented and all experimental data rather than only part of the data, as has often been done in the past.
Oxygen Reduction In A Proton Exchange Membrane Test Cell, S. J. Ridge, Ralph E. White, Y. Tsou, R. N. Beaver, G. A. Eisman
Oxygen Reduction In A Proton Exchange Membrane Test Cell, S. J. Ridge, Ralph E. White, Y. Tsou, R. N. Beaver, G. A. Eisman
Faculty Publications
Oxygen reduction in a gas-fed porous electrode attached to a proton exchange membrane is discussed. Experimental data and a mathematical model are presented for the test cell used. Various membrane and electrode assemblies were tested at different levels of platinum loading and Teflon® content. The model accounts for the diffusion and reaction of oxygen and the diffusion and reaction of hydrogen ions. Sulfuric acid was placed above the membrane in the test cell reservoir to provide a source of protons for the reduction of oxygen at the cathode. Based upon model predictions, it is shown that the transport of the …
Utility Of An Empirical Method Of Modeling Combined Zero Gap/Attached Electrode Membrane Chlor-Alkali Cells, Clifford W. Walton, Ralph E. White
Utility Of An Empirical Method Of Modeling Combined Zero Gap/Attached Electrode Membrane Chlor-Alkali Cells, Clifford W. Walton, Ralph E. White
Faculty Publications
An extensive survey of the Docktor-Ingenieur Dissertationen of Jakob Jörissen and Klaus-R. Menschig, both originally from the Universität Dortmund, is presented in regard to the empirical modeling of membrane chlor-alkali cells and how it can be applied to a combined zero gap/attached porous electrode layer membrane cell. Particular emphasis isplaced on Menschig's work on zero gap (ZG) and attached porous electrode layer (APEL) membrane chlor-alkali cells, the first such research to appear in the open literature. Menschig developed various computer programs to characterize these ZG and APEL membrane chlor-alkali cells. He characterized these cells by using the following parameters: the …