Academic literature on the topic 'Reactive electrochemical membranes'
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Journal articles on the topic "Reactive electrochemical membranes"
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Yang, Kui, Hui Lin, Shangtao Liang, Ruzhen Xie, Sihao Lv, Junfeng Niu, Jie Chen, and Yongyou Hu. "A reactive electrochemical filter system with an excellent penetration flux porous Ti/SnO2–Sb filter for efficient contaminant removal from water." RSC Advances 8, no. 25 (2018): 13933–44. http://dx.doi.org/10.1039/c8ra00603b.
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Misal, Saurabh N., Meng-Hsuan Lin, Shafigh Mehraeen, and Brian P. Chaplin. "Modeling electrochemical oxidation and reduction of sulfamethoxazole using electrocatalytic reactive electrochemical membranes." Journal of Hazardous Materials 384 (February 2020): 121420. http://dx.doi.org/10.1016/j.jhazmat.2019.121420.
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Winter, Lea R., and Menachem Elimelech. "(Invited) Electrified Membranes for Transformation of Nitrate in Wastewaters." ECS Meeting Abstracts MA2022-01, no. 40 (July 7, 2022): 1798. http://dx.doi.org/10.1149/ma2022-01401798mtgabs.
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The release of nitrate to the environment from wastewater effluent and agricultural runoff contributes to groundwater contamination, harmful algal blooms, and disruption of biogeochemical nitrogen flows. Typical treatment methods are based on nitrate separation, which produces waste streams that are often discharged to the environment. Alternatively, nitrate conversion via electrochemical reduction eliminates the production of concentrated waste streams while avoiding the addition of reductant or hole scavenger chemicals to accomplish the reaction. However, major challenges for nitrate removal from water via electrochemical conversion involve reducing the use of expensive precious metal electrocatalysts while also improving the reaction activity and selectivity, catalyst stability, and mass transport of nitrate to electrocatalyst active sites. The use of electrochemical membranes as multifunctional porous flow-through electrodes could potentially address these challenges based on improved mass transport and altered kinetics under flow conditions within membrane pores. Conductive membranes were fabricated using polymers combined with carbonaceous materials such as reduced graphene oxide (rGO) and carbon nanotubes. The rGO was functionalized with non-precious transition metal oxynitride electrocatalysts, where these catalysts showed higher nitrate conversion activity compared to the unsupported transition metal nitrides. The influence of catalyst materials, membrane fabrication process, and filtration conditions on nitrate reduction activity and selectivity were evaluated. In addition to the environmental impacts of closing the nitrogen loop by converting nitrate into innocuous N2, selective nitrate reduction to ammonia provides opportunities for recovery as fertilizer or carbon-free renewable energy storage. The prospects for reactive nitrogen recovery based on nitrate electrochemical conversion to ammonia were analyzed for various potential source waters.
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Trellu, Clément, Brian P. Chaplin, Clémence Coetsier, Roseline Esmilaire, Sophie Cerneaux, Christel Causserand, and Marc Cretin. "Electro-oxidation of organic pollutants by reactive electrochemical membranes." Chemosphere 208 (October 2018): 159–75. http://dx.doi.org/10.1016/j.chemosphere.2018.05.026.
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Almassi, Soroush, Zhao Li, Wenqing Xu, Changcheng Pu, Teng Zeng, and Brian P. Chaplin. "Simultaneous Adsorption and Electrochemical Reduction of N-Nitrosodimethylamine Using Carbon-Ti4O7Composite Reactive Electrochemical Membranes." Environmental Science & Technology 53, no. 2 (December 14, 2018): 928–37. http://dx.doi.org/10.1021/acs.est.8b05933.
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Gu, Liankai, Yonghao Zhang, Weiqing Han, and Kajia Wei. "Membrane Fouling and Electrochemical Regeneration at a PbO2-Reactive Electrochemical Membrane: Study on Experiment and Mechanism." Membranes 12, no. 8 (August 22, 2022): 814. http://dx.doi.org/10.3390/membranes12080814.
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Membrane fouling and regeneration are the key issues for the application of membrane separation (MS) technology. Reactive electrochemical membranes (REMs) exhibited high, stable permeate flux and the function of chemical-free electrochemical regeneration. This study fabricated a micro-filtration REM characterized by a PbO2 layer (PbO2-REM) to investigate the electro-triggered anti-fouling and regeneration progress within REMs. The PbO2-REM exhibited a three-dimensional porous structure with a few branch-like micro-pores. The PbO2-REM could alleviate Humic acid (HA) and Bisphenol A (BPA) fouling through electrochemical degradation combined with bubble migration, which achieved the best anti-fouling performance at current density of 4 mA cm−2 with 99.2% BPA removal. Regeneration in the electro-backwash (e-BW) mode was found as eight times that in the forward wash and full flux recovery was achieved at a current density of 3 mA cm−2. EIS and simulation study also confirmed complete regeneration by e-BW, which was ascribed to the air–water wash formed by bubble migration and flow. Repeated regeneration tests showed that PbO2-REM was stable for more than five cycles, indicating its high durability for practical uses. Mechanism analysis assisted by finite element simulation illustrated that the high catalytic PbO2 layer plays an important role in antifouling and regeneration.
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Zaky, Amr M., and Brian P. Chaplin. "Porous Substoichiometric TiO2 Anodes as Reactive Electrochemical Membranes for Water Treatment." Environmental Science & Technology 47, no. 12 (June 5, 2013): 6554–63. http://dx.doi.org/10.1021/es401287e.
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Guo, Lun, Yin Jing, and Brian P. Chaplin. "Development and Characterization of Ultrafiltration TiO2 Magnéli Phase Reactive Electrochemical Membranes." Environmental Science & Technology 50, no. 3 (January 20, 2016): 1428–36. http://dx.doi.org/10.1021/acs.est.5b04366.
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Skolotneva, Ekaterina, Marc Cretin, and Semyon Mareev. "A Simple 1D Convection-Diffusion Model of Oxalic Acid Oxidation Using Reactive Electrochemical Membrane." Membranes 11, no. 6 (June 7, 2021): 431. http://dx.doi.org/10.3390/membranes11060431.
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In recent years, electrochemical methods utilizing reactive electrochemical membranes (REM) have been recognized as the most promising technologies for the removal of organic pollutants from water. In this paper, we propose a 1D convection-diffusion-reaction model concerning the transport and oxidation of oxalic acid (OA) and oxygen evolution in the flow-through electrochemical oxidation system with REM. It allows the determination of unknown parameters of the system by treatment of experimental data and predicts the behavior of the electrolysis setup. There is a good agreement in calculated and experimental data at different transmembrane pressures and initial concentrations of OA. The model provides an understanding of the processes occurring in the system and gives the concentration, current density, potential, and overpotential distributions in REM. The dispersion coefficient was determined as a fitting parameter and it is in good agreement with literary data for similar REMs. It is shown that the oxygen evolution reaction plays an important role in the process even under the kinetic limit, and its contribution decreases with increasing total organic carbon flux through the REM.
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Gayen, Pralay, Chen Chen, Jeremiah T. Abiade, and Brian P. Chaplin. "Electrochemical Oxidation of Atrazine and Clothianidin on Bi-doped SnO2–TinO2n–1 Electrocatalytic Reactive Electrochemical Membranes." Environmental Science & Technology 52, no. 21 (September 21, 2018): 12675–84. http://dx.doi.org/10.1021/acs.est.8b04103.
Full textDissertations / Theses on the topic "Reactive electrochemical membranes"
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Stuckey, Philip A. "Kinetic Studies and Electrochemical Processes at Fuel Cell Electrodes." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1322675454.
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Chen, PoYun. "Role of Ionic Liquid in Electroactive Polymer Electrolyte Membrane for Energy Harvesting and Storage." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1590688110146547.
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ORCIL, KERVAJAN LOUISIANE. "Etude de l'influence des cinetiques d'echange sur les processus de transport dans les electrolytes." Paris 6, 1987. http://www.theses.fr/1987PA066561.
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Dubouis, Michel. "Régénération de la soude à partir de solutions de carbonate de sodium par des procédés électromembranaires." Grenoble INPG, 1993. http://www.theses.fr/1993INPG0051.
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Differents procedes electromembranaires sont concus et etudies pour regenerer de la soude a partir de solutions de carbonate de sodium. En presence d'especes oxydables en faibles quantites, la regeneration s'effectue avec une cellule a une seule membrane permselective echangeuse de cations. Pour eviter l'oxydation de ces especes, par exemple le sulfure (na#2s) de la liqueur verte du procede kraft, le procede electromembranaire le plus adapte par sa simplicite et par sa capacite de fonctionnement sur le long terme, est constitue d'un electrolyseur a deux membranes echangeuses de cations, precede d'un reacteur d'acidification pour le degagement des gaz; dans la boucle reacteur-compartiment central de la cellule d'electrolyse, circule une solution de sulfate de sodium acidifiee. Une autre configuration de l'electrolyseur du procede est envisagee et testee avec une membrane echangeuse d'anions et une membrane echangeuse de cations suivant le procede classique d'electro-electrodialyse du sulfate de sodium. Ce procede est aussi compare a un electrolyseur a deux membranes echangeuses de cations avec introduction directe de la solution de carbonate et de sulfure de sodium dans le compartiment central ou se produit le degagement des gaz. Les membranes echangeuses de cations et plus particulierement les membranes echangeuses d'anions, separant le compartiment anodique du compartiment central de l'electrolyseur, sont etudiees par la methode des radiotraceurs et par spectrometrie raman. Ces procedes produisent de la soude qui peut etre aussi concentree que dans le procede chlore-soude a membrane et de l'hydrogene relativement pur dont l'utilisation par une anode a hydrogene est testee. Finalement, si les problemes d'environnement remettent en cause le procede bien etabli du four a chaux, la rentabilite de ces differents procedes devra etre reconsideree
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Safa, Mohamad. "Modélisation réduite de la pile à combustible en vue de la surveillance et du diagnostic par spectroscopie d'impédance." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00855160.
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Cette thèse porte sur la modélisation des piles à combustible à membrane d'échange de protons (PEMFC), en vue de leur surveillance et de leur diagnostic par spectroscopie d'impédance. La première partie du document présente le principe de fonctionnement de ces piles, ainsi que l'état de l'art de la modélisation et des méthodes de surveillance et diagnostic. Le modèle physique multi échelle particulièrement détaillé publié en 2005 par A.A. Franco sert de point de départ. Il est simplifié de façon à aboutir à un système d'équations aux dérivées partielles en une unique dimension spatiale. L'objectif principal de la seconde partie est l'analyse harmonique du fonctionnement de la pile. En s'inspirant de travaux classiques sur l'analyse géométrique de réseaux de réactions électrochimiques, un modèle réduit compatible avec la thermodynamique est obtenu. Cette classe de systèmes dynamiques permet de déterminer, pour un tel réseau, une formule analytique de l'impédance de l'anode et de la cathode d'une pile PEMFC. Un modèle complet de la pile est obtenu en connectant ces éléments à des éléments représentant la membrane, les couches diffuses et les couches de diffusion des gaz. Les modèles précédents supposent la pile représentée par une cellule unique et homogène. Afin de permettre d'en décrire les hétérogénéités spatiales, nous proposons finalement un résultat de modélisation réduite d'un réseau de cellules représentées par leur impédance. Ce modèle approxime l'impédance globale du réseau par une "cellule moyenne", connectée à deux cellules "série" et "parallèle" représentatives d'écart par rapport à la moyenne.
Book chapters on the topic "Reactive electrochemical membranes"
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Doraiswamy, L. K. "Other Important (and Some Lesser Known) Strategies of Rate Enhancement." In Organic Synthesis Engineering. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195096897.003.0035.
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The literature contains examples of several strategies of rate enhancement not covered in the previous chapters. Many of these are essentially strategies for individual reactions with little general appeal. On the other hand, a few are very important, and several others combine two or more strategies. Of these, photochemical and micellar enhancements are as important as the strategies considered earlier in this part. However, in photochemical enhancement, recent studies have shown that the basis of scale-up used so far is questionable (Cassano et al., 1995), and designs based on newer concepts are still in their infancy. In micellar catalysis, despite the advances made, there are few industrial applications. As a result, these are included in this chapter on other strategies. Hydrotropes and supercritical fluids, although “old” with respect to other uses, are emerging as strong contenders for rate enhancement and ease of processing. Hence these two strategies are considered at some length in this chapter. Also included are the use of microwaves and several combinatorial strategies such as PTC with electrochemical, enzymatic, or sonochemical techniques; the use of supercritical fluids in similar combinations; enzymatic reactions in micelles; and PTC reactions in supercritical fluids or membrane reactors. Interaction of light with a chemical species can initiate or enhance a chemical reaction. Reactions of this type are known as photochemical reactions. Of the many distinctive features of photochemistry, the following is particularly noteworthy: in thermal excitation processes, all three forms of energy, electronic, transational, and rotational, are raised to higher levels. In contrast, photoexcitation raises only the electronic energy level which leads to higher selectivity, as exemplified by the photochlorination of the methyl group of toluene without any ring chlorination. Further, photochemical reactions are ecologically clean and require much less aggressive methods than conventional syntheses. Examples of reactions initiated or enhanced by light are many, and a small number are in industrial use, particularly in the production of halogenated hydrocarbons, alkane sulfates, and fine organic chemicals, including vitamins and fragrances. But the potential is enormous.
Conference papers on the topic "Reactive electrochemical membranes"
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Katukota, Shanthi P., Jianhu Nie, Yitung Chen, Robert F. Boehm, and Hsuan-Tsung Hsieh. "Numerical Modeling of Electrochemical Process for Hydrogen Production From PEM Electrolyzer Cell." In ASME 2007 Energy Sustainability Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/es2007-36108.
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Numerical simulations of proton exchange water electrolysis for hydrogen production were performed for the purpose of examining the phenomena occurring within the proton exchange membranes (PEM) water splitting cell. A two-dimensional steady-state isothermal model of the cell has been developed. Finite element method was used to solve the multicomponent transport model coupled with flow in porous medium, charge balance and electrochemical kinetics. The Maxwell-Stefan equation is applied for the multi-component diffusion and convection in water distribution electrodes. The Butler-Volmer kinetic equation is used to obtain the local current density distribution at the catalyst reactive boundaries. Darcy’s law was applied for the flow of species in the porous electrodes. Parametric studies are performed based on appropriate mass balances, transport, and electrochemical kinetics applied to the electrolysis cell. There are significant current spikes present at the corners of the current collector. The current density varies significantly in the cell, being highest at the corners of the current collector. As the water on the anode side flows from the inlet to the outlet, the mass fraction of oxygen increases. This is the effect of oxygen concentration due to the effect oxidation of water. On the cathode side, as the mass fraction of water decreases there is little variation in the hydrogen mass fraction content due to the effect of hydrogen reduction.
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Djilali, N., and T. Berning. "Computational Modelling and Simulation of Proton-Exchange Membrane Fuel Cells (Keynote)." In ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1560.
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Fuel cells (FC’s) are electrochemical devices that convert directly into electricity the chemical energy of reaction of a fuel (usually hydrogen) with an oxidant (usually oxygen from ambient air). The only by-products in a hydrogen fuel cell are heat and water, making this emerging technology the leading candidate for quiet, zero emission energy production. Several types of fuel cell are currently undergoing intense research and development for applications ranging from portable electronics and appliances to residential power generation and transportation. The focus of this lecture is Proton-Exchange Membrane Fuel Cells (PEMFC’s). An electrolyte consisting of a “solid” polymer membrane, low operating temperatures (typically below 90 °C) and a relatively simple design combine to make PEMFC’s particularly well suited to automotive and portable applications. The operation of a fuel cell relies on electrochemical reactions and an array of coupled transport phenomena, including multi-component gas flow, two phase-flow, heat and mass transfer, phase change and transport of charged species. The transport processes take place in variety of media, including porous gas diffusion electrodes and polymer membranes. The fuel cell environment makes it impossible to measure in-situ the quantities of interest to understand and quantify these phenomena, and computational modelling and simulations are therefore poised to play a central role in the development and optimization of fuel cell technology. We provide an overview of the role of various transport phenomena in fuel cell operation and some of the physical and computational modelling challenges they present. The processes will be illustrated through examples of multi-dimensional numerical simulations of Proton-Exchange Membrane Fuel Cells. We close with a perspective on some of the many remaining challenges and future development opportunities.
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Garza, Gladys, Peiwen Li, and Douglas Loy. "Micro-Fluidic Assisted Passive Direct Methanol Fuel Cells." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-88540.
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A novel design of micro-fluidic structure has been proposed to facilitate passive methanol supply and ventilation of carbon dioxide in direct methanol fuel cells (DMFC). Experimental study was conducted for three in-house fabricated cells which have different membrane-electrode-assemblies (MEA) and cathode-side air-breathing current collectors. Low rate of passive methanol supply and control was accomplished through capillary-force-driven mass transfer in the in-plane of carbon paper wicks. The low methanol supply rate using this passive method only meets the need of fuel of the electrochemical reaction, and there is almost no surplus methanol that could cross over the membrane. The micro-fluidic structure on the anode plate also makes passive removal of the CO2 gas from the electrochemical reaction. The influence of the concentration of methanol and cell operation temperature was examined and compared in the study. The results reveal very promising performance in the passive DMFCs when a methanol concentration is above 8M.
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Babiniec, Sean M., Andrea Ambrosini, and James E. Miller. "Renewable Hydrogen Production via Thermochemical/Electrochemical Coupling." In ASME 2019 13th International Conference on Energy Sustainability collocated with the ASME 2019 Heat Transfer Summer Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/es2019-3905.
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Abstract A coupled thermochemical/electrochemical cycle was investigated to produce hydrogen from renewable resources. Like a conventional thermochemical cycle, this approach leverages chemical energy stored in a thermochemical working material that is reduced thermally by solar energy. However, in this concept, the stored chemical energy provides only a fraction of the energy required for effectively splitting steam to produce hydrogen. To push the reaction towards completion, an electrically-assisted proton-conducting membrane is employed to separate and recover hydrogen as it is produced. This novel coupled-cycle concept provides several benefits. First, the required oxidation enthalpy of the reversible thermochemical material is decreased, enabling the process to occur at lower temperatures. Second, removing the requirement for spontaneous steam splitting widens the scope of materials compositions, allowing for less expensive/more abundant elements to be used. Lastly, thermodynamics calculations suggest that this concept can potentially reach higher efficiencies than photovoltaic-to-electrolysis hydrogen production. A novel thermochemical/electrochemical test stand was conceptualized and constructed to prove the concept, and the practical feasibility of the proposed coupled cycle was assessed by validating the individual components of the system: proton conduction across a BaCe0.1Zr0.8Y0.1O3-δ (BCZY18) membrane, thermochemical activity of the CaAl0.2Mn0.8O3−δ (CAM28) working material reduced at 650 °C, and indirect observation of hydrogen production.
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Mishler, Jeffrey, Yun Wang, Roger Lujan, Rodney L. Borup, and Rangachary Mukundan. "Performance of PEM Fuel Cells at Sub-Freezing Temperatures." In ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology collocated with ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/fuelcell2011-54654.
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The ability of the polymer electrolyte fuel cell to start up at sub-freezing temperatures, also called cold start, is paramount for its transportation application. The ability to cold start is governed by whether the fuel cell is able to overcome 0 °C before the produced ice terminates the electrochemical reaction. Therefore, fundamental understanding of the fuel cell performance at sub-freezing temperatures is highly needed to improve its cold start characteristics. In this work, we investigated the fuel cell sub-freezing operation through experimental investigation. PEFCs using various membranes and catalyst layer configurations were constructed. In particular, various catalyst layer thickness, ionomer-catalyst ratios, RHs, and membrane thicknesses were considered, and their influence on fuel cell cold start performance was investigated. The voltage, current, high-frequency resistance, and the coulombs passed before failure were recorded and presented to reveal the fuel cell cold start operation. Further, a simplified analysis of cold start was performed based on an electrode model. The cell voltage evolution and solid water build up were predicted and compared with the experimental data.
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Willsey, Aliza M., Thomas S. Welles, and Jeongmin Ahn. "Advancements in Nitric Oxide Emission Control With a Perovskite Based Membrane via High Frequency Electric Potential Oscillations." In ASME 2022 Power Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/power2022-85154.
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Abstract Increased concerns over climate change, limited fossil fuel resources, emissions, and poor air quality has created a greater need for sustainable energy systems. The need for increased sustainable energy systems has created largely two cooperative movements: 1) technologies that are considered renewable or more environmentally friendly and 2) higher efficiency. The automotive industry has long been a target for increasing efficiency and decreasing environmentally harmful emissions. The combustion of hydrocarbon fuels results in harmful and reactive incomplete combustion byproducts. Fully electric and hybrid powertrains are increasing in commonality but have not yet fully penetrated the market. Many automobile manufacturers are still producing vehicles which rely solely on the internal combustion engine and hydrocarbon-based fuels. Currently, manufacturers utilize a combination of three-way catalytic converters and nitrogen oxide traps to rid the exhaust flow of harmful combustion emissions. Catalytic converters use expensive precious platinum group metals (PGM) to simultaneously react unwanted hydrocarbon, carbon monoxide, and nitrogen oxides into less harmful, complete products of combustion, such as nitrogen, carbon dioxide, and water vapor. However, the performance of these devices is highly dependent upon the equivalence ratio of the exhaust. Three-way catalysts require that the exhaust remain at stoichiometric conditions for optimal performance. Prolonged fuel lean engine operation renders the PGM catalyst incapable of reacting nitrogen oxide emissions. Nitrogen oxide, and more specifically nitric oxide (NO), emissions are of significant concern, as such emissions directly contribute to increased smog, acid rain, climate change, and respiratory inflammation within the population. Lean nitrogen oxide traps (LNTs) are incorporated into the exhaust system to temporarily capture excess nitrogen oxide emissions. However, the zeolite-based materials used in LNTs have a finite limit on nitrogen oxide storage capacity. Once nitrogen oxide capacity is reached, the engine must enter a fuel rich combustion condition or additional reactants must be injected directly into the exhaust system to regenerate the LNT’s function. Therefore, current exhaust treatment measures introduce significant complexity into the exhaust system and significant constraints on engine operation. As such, this work investigates the potential for new exhaust treatment materials, capable of maintaining performance across all conditions. Specifically, this work investigates the NO reduction potential of a multilayered ceramic electrochemical catalytic membrane. Prior work has demonstrated that the natural electric potential oscillation, which develops across such a membrane, significantly reduces NO emissions. The ceramic membrane, consisting of two dissimilar metal electrodes, sandwiching a dielectric layer, is able to achieve an NO reduction in excess of 2X that of a traditional PGM three-way catalytic converter [1]. Here, the possibility for externally inducing a low magnitude (< 500 mVpp), high frequency (> 1kHz) electric potential oscillation across the reacting membrane and increasing the conversion of NO into diatomic nitrogen and oxygen is investigated. Electric potential oscillation at the surface generates an altered electrochemical reaction pathway. During the breakdown of NO, N2O is recorded as an intermediate species without the introduction of NH3. This result diverges from traditional theory, which predicts the formation of NO2. This work further explores the relation between externally applied electric potential oscillation, N2O formation, and reduction of NO.
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Yu, Sangseok, Dohoy Jung, and Dennis N. Assanis. "Numerical Modeling of the Proton Exchange Membrane Fuel Cell for Thermal Management." In ASME 2006 4th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2006. http://dx.doi.org/10.1115/fuelcell2006-97062.
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A thermal model of the Proton Exchange Membrane Fuel Cell (PEMFC) was developed to investigate the performance of a large active area fuel cell with the water cooling thermal management system. The model includes three sub-models: water transport model, electrochemical reaction model and heat transfer model. The water transport model calculates water distribution and the electric resistance of the membrane electrolyte. The electrochemical reaction model for the agglomerate structure cathode catalyst layer predicts the cathode overpotentials including mass transport limitation effect at high current density region. Two-dimensional heat transfer model incorporated with coolant and gas channels predicts the temperature distribution within the fuel cell. By integrating those sub-models, local electric resistance and overpotentials depending on the water and temperature distribution can be predicted. The model was calibrated with published experimental data and sensitivity studies were performed. The effects of the inlet gas temperature and humidity on the fuel cell performance were explored. In addition, the effect of the temperature distribution, and accordingly the electric resistance distribution within the fuel cell depending on the coolant temperature and flowrate was investigated. The results shows that the change in the local electric resistance due to temperature distribution eventually causes fuel cell power decrease and it is also concluded that the coolant temperature and flowrate should be controlled properly depending on the operating conditions in order to minimize the temperature distribution while maximizing power output of the fuel cell.
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Marr, Curtis, and Xianguo Li. "Composition and Performance Optimization of Catalyst Layer in a Proton Exchange Membrane Fuel Cell." In ASME 1997 Turbo Asia Conference. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/97-aa-075.
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The composition and performance optimisation of cathode catalyst platinum and catalyst layer structure in a proton exchange membrane fuel cell has been investigated by including both electrochemical reaction and mass transport process. It is found that electrochemical reactions occur in a thin layer within a few micrometers thick, indicating ineffective catalyst utilization for the present catalyst layer design. The effective use of platinum catalyst decreases with increasing current density, hence lower loadings of platinum are feasible for higher current densities of practical interest without adverse effect on cell performance. The optimal void fraction for the catalyst layer is about 60% and fairly independent of current density, and a 40% supported platinum catalyst yields the best performance amongst various supported catalysts investigated. An optimal amount of membrane content in the void region of the catalyst layer exists for minimum cathode voltage losses due to competition between proton migration through the membrane and oxygen transfer in the void region. The present results will be useful for practical fuel cell designs.
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Babaie Rizvandi, Omid, and Serhat Yesilyurt. "Modeling of Flow Distribution in Proton Exchange Membrane Fuel Cell." In ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icnmm2018-7658.
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Analysis and design of flow fields for proton exchange membrane fuel cell (PEMFC) require coupled solution of the flow fields, gas transport and electrochemical reaction kinetics in the anode and the cathode. Computational cost prohibits the widespread use of three-dimensional models of the anode and cathode flow fields, gas diffusion layers (GDL), catalyst layers (CL) and the membrane for fluid flow and mass transport. On the other-hand, detailed cross-sectional two-dimensional models cannot resolve the effects of the anode and cathode flow field designs. Here, a two-dimensional in-plane model is developed for the resolution of the effects of anode and cathode flow channels and GDLs, catalyst layers are treated as thin-layers of reaction interfaces and the membrane is considered as a thin-layer that resist the transfer of species and the ionic current. Brinkman equations are used to model the in-plane flow distribution in the channels and the GDLs to account for the momentum transport in the channels and the porous GDLs. Fick’s law equations are used to model transport of gas species in the channels and GDLs by advection and diffusion mechanisms, and electrochemical reactions in the CL interfaces are modeled by Butler-Volmer equations. Complete features of the flow in the channels and inlet and outlet manifolds are included in the model using resistance relationships in the through-plane direction. The model is applied to a small cell having an active area of 1.3 cm2 and consisting of 8 parallel channels in the anode and a double serpentine in the cathode. Effects of the anode and cathode stoichiometric ratios on the cell performance and hydrogen utilization are investigated. Results demonstrate that for a sufficiently high cathode stoichiometric ratio enough, anode stoichiometric ratio can be lowered to unity to obtain very high hydrogen utilization and output power.
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Wang, Yun. "3D Modeling of Polymer Electrolyte Fuel Cell and Hydride Hydrogen Storage Tank." In ASME 2010 4th International Conference on Energy Sustainability. ASMEDC, 2010. http://dx.doi.org/10.1115/es2010-90138.
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3D dynamic models are developed for polymer electrolyte fuel cells (PEFCs) and hydrogen tanks, respectively. In the fuel cell model, we consider the major transport and electrochemical processes within the key components of a single PEFC that govern fuel cell transient including the electrochemical double-layer behavior, mass/heat transport, liquid water dynamics, and membrane water uptake. As to modeling hydrogen tanks, we consider a LaNi5-based system and develop a general formula that describes hydrogen absorption/desorption. The model couples the hydride reaction kinetics and mass/heat transport. The dynamic characteristics of the PEFC and hydrogen tank, together with the possible coupling of the two systems, are discussed.
Reports on the topic "Reactive electrochemical membranes"
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Delwiche, Michael, Boaz Zion, Robert BonDurant, Judith Rishpon, Ephraim Maltz, and Miriam Rosenberg. Biosensors for On-Line Measurement of Reproductive Hormones and Milk Proteins to Improve Dairy Herd Management. United States Department of Agriculture, February 2001. http://dx.doi.org/10.32747/2001.7573998.bard.
Full textAbstract:
The original objectives of this research project were to: (1) develop immunoassays, photometric sensors, and electrochemical sensors for real-time measurement of progesterone and estradiol in milk, (2) develop biosensors for measurement of caseins in milk, and (3) integrate and adapt these sensor technologies to create an automated electronic sensing system for operation in dairy parlors during milking. The overall direction of research was not changed, although the work was expanded to include other milk components such as urea and lactose. A second generation biosensor for on-line measurement of bovine progesterone was designed and tested. Anti-progesterone antibody was coated on small disks of nitrocellulose membrane, which were inserted in the reaction chamber prior to testing, and a real-time assay was developed. The biosensor was designed using micropumps and valves under computer control, and assayed fluid volumes on the order of 1 ml. An automated sampler was designed to draw a test volume of milk from the long milk tube using a 4-way pinch valve. The system could execute a measurement cycle in about 10 min. Progesterone could be measured at concentrations low enough to distinguish luteal-phase from follicular-phase cows. The potential of the sensor to detect actual ovulatory events was compared with standard methods of estrus detection, including human observation and an activity monitor. The biosensor correctly identified all ovulatory events during its testperiod, but the variability at low progesterone concentrations triggered some false positives. Direct on-line measurement and intelligent interpretation of reproductive hormone profiles offers the potential for substantial improvement in reproductive management. A simple potentiometric method for measurement of milk protein was developed and tested. The method was based on the fact that proteins bind iodine. When proteins are added to a solution of the redox couple iodine/iodide (I-I2), the concentration of free iodine is changed and, as a consequence, the potential between two electrodes immersed in the solution is changed. The method worked well with analytical casein solutions and accurately measured concentrations of analytical caseins added to fresh milk. When tested with actual milk samples, the correlation between the sensor readings and the reference lab results (of both total proteins and casein content) was inferior to that of analytical casein. A number of different technologies were explored for the analysis of milk urea, and a manometric technique was selected for the final design. In the new sensor, urea in the sample was hydrolyzed to ammonium and carbonate by the enzyme urease, and subsequent shaking of the sample with citric acid in a sealed cell allowed urea to be estimated as a change in partial pressure of carbon dioxide. The pressure change in the cell was measured with a miniature piezoresistive pressure sensor, and effects of background dissolved gases and vapor pressures were corrected for by repeating the measurement of pressure developed in the sample without the addition of urease. Results were accurate in the physiological range of milk, the assay was faster than the typical milking period, and no toxic reagents were required. A sampling device was designed and built to passively draw milk from the long milk tube in the parlor. An electrochemical sensor for lactose was developed starting with a three-cascaded-enzyme sensor, evolving into two enzymes and CO2[Fe (CN)6] as a mediator, and then into a microflow injection system using poly-osmium modified screen-printed electrodes. The sensor was designed to serve multiple milking positions, using a manifold valve, a sampling valve, and two pumps. Disposable screen-printed electrodes with enzymatic membranes were used. The sensor was optimized for electrode coating components, flow rate, pH, and sample size, and the results correlated well (r2= 0.967) with known lactose concentrations.