The Experts below are selected from a list of 198 Experts worldwide ranked by ideXlab platform
Jay L. Perry - One of the best experts on this subject based on the ideXlab platform.
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Microlith-Based Catalytic Reactor for Air Quality and Trace Contaminant Control Applications
2015Co-Authors: Saurabh Vilekar, Kyle Hawley, Christian Junaedi, Bruce Crowder, Julian Prada, Richard Mastanduno, Jay L. Perry, Matthew J. KayatinAbstract:Traditionally, gaseous compounds such as methane, carbon monoxide, and Trace Contaminants have posed challenges for maintaining clean air in enclosed spaces such as crewed spacecraft cabins as they are hazardous to humans and are often difficult to remove by conventional adsorption technology. Catalytic oxidizers have provided a reliable and robust means of disposing of even Trace levels of these compounds by converting them into carbon dioxide and water. Precision Combustion, Inc. (PCI) and NASA – Marshall (MSFC) have been developing, characterizing, and optimizing high temperature catalytic oxidizers (HTCO) based on PCI’s patented Microlith ® technology to meet the requirements of future extended human spaceflight explorations. Current efforts have focused on integrating the HTCO unit with a compact, simple recuperative heat exchanger to reduce the overall system size and weight while also reducing its energy requirements. Previous efforts relied on external heat exchangers to recover the waste heat and recycle it to the oxidizer to minimize the system’s power requirements; however, these units contribute weight and volume burdens to the overall system. They also result in excess heat loss due to the separation of the HTCO and the heat recuperator, resulting in lower overall efficiency. Improvements in the recuperative efficiency and close coupling of HTCO and heat recuperator lead to reductions in system energy requirements and startup time. Results from testing HTCO units integrated with heat recuperators at a variety of scales for cabin air quality control and heat melt compactor applications are reported and their benefits over previous iterations of the HTCO and heat recuperator assembly are quantified in this paper.
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an assessment of the international space station s Trace Contaminant control subassembly process economics
2013Co-Authors: Jay L. Perry, Harold Cole, H N EllessyAbstract:The International Space Station (ISS) Environmental Control and Life Support System includes equipment speci.cally designed to actively remove Trace chemical contamination from the cabin atmosphere. In the U.S. on-orbit segment, this function is provided by the Trace Contaminant control subassembly (TCCS) located in the atmosphere revitalization subsystem rack housed in the laboratory module, Destiny. The TCCS employs expendable adsorbent beds to accomplish its function leading to a potentially signi.cant life cycle cost over the life of the ISS. Because maintaining the TCCSs proper can be logistically intensive, its performance in .ight has been studied in detail to determine where savings may be achieved. Details of these studies and recommendations for improving the TCCS s process economics without compromising its performance or crew health and safety are presented and discussed.
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a comparison of photocatalytic oxidation reactor performance for spacecraft cabin Trace Contaminant control applications
41st International Conference on Environmental Systems, 2011Co-Authors: Jay L. Perry, Kenneth R Frederick, Joseph P Scott, Dana N ReinermannAbstract:Photocatalytic oxidation (PCO) is a maturing process technology that shows potential for spacecraft life support system application. Incorporating PCO into a spacecraft cabin atmosphere revitalization system requires an understanding of basic performance, particularly with regard to partial oxidation product production. Four PCO reactor design concepts have been evaluated for their effectiveness for mineralizing key Trace volatile organic compounds (VOC) typically observed in crewed spacecraft cabin atmospheres. Mineralization efficiency and selectivity for partial oxidation products are compared for the reactor design concepts. The role of PCO in a spacecraft’s life support system architecture is discussed.
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microlith based structured sorbent for carbon dioxide humidity and Trace Contaminant control in manned space habitats
41st International Conference on Environmental Systems, 2011Co-Authors: Christian Junaedi, Jay L. Perry, Subir Roychoudhury, David F Howard, James C KnoxAbstract:To support continued manned space exploration, the development of atmosphere revitalization systems that are lightweight, compact, durable, and power efficient is a key challenge. The systems should be adaptable for use in a variety of habitats and should offer operational functionality to either expel removed constituents or capture them for closedloop recovery. As mission durations increase and exploration goals reach beyond low earth orbit, the need for regenerable adsorption processes for continuous removal of CO2 and Trace Contaminants from cabin air becomes critical. Precision Combustion, Inc. (PCI) and NASA Marshall (MSFC) have been developing an Engineered Structured Sorbents (ESS) approach based on PCI s patented Microlith technology to meet the requirements of future, extended human spaceflight explorations. This technology offers the inherent performance and safety attributes of zeolite and other sorbents with greater structural integrity, regenerability, and process control, thereby providing potential durability and efficiency improvements over current state-of-the-art systems. The major advantages of the ESS explored in this study are realized through the use of metal substrates to provide structural integrity (i.e., less partition of sorbents) and enhanced thermal control during the sorption process. The Microlith technology also offers a unique internal resistive heating capability that shows potential for short regeneration time and reduced power requirement compared to conventional systems. This paper presents the design, development, and performance results of the integrated adsorber modules for removing CO2, water vapor, and Trace chemical Contaminants. A related effort that utilizes the adsorber modules for sorption of toxic industrial chemicals is also discussed. Finally, the development of a 4-person two-leg ESS system for continuous CO2 removal is also presented.
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root cause assessment of pressure drop rise of a packed bed of lithium hydroxide in the international space station Trace Contaminant control system
SAE International Journal of Aerospace, 2009Co-Authors: Tatiana Aguilera, Jay L. PerryAbstract:The Trace Contaminant control system (TCCS) located in the International Space Station s (ISS) U.S. laboratory module employs physical adsorption, thermal catalytic oxidation, and chemical adsorption to remove Trace chemical contamination produced by equipment offgassing and anthropogenic sources from the cabin atmosphere. The chemical adsorption stage, consisting of a packed bed of granular lithium hydroxide (LiOH), is located after the thermal catalytic oxidation stage and is designed to remove acid gas byproducts that may be formed in the upstream oxidation stage. While in service on board the ISS, the LiOH bed exhibited a change in flow resistance that leading to flow control difficulties in the TCCS. Post flight evaluation revealed LiOH granule size attrition among other changes. An experimental program was employed to investigate mechanisms hypothesized to contribute to the change in the packed bed s flow resistance. Background on the problem is summarized, including a discussion of likely mechanisms. The experimental program is described, results are presented, and implications for the future are discussed.
Jon Chorover - One of the best experts on this subject based on the ideXlab platform.
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Trace Contaminant concentration affects mineral transformation and pollutant fate in hydroxide weathered hanford sediments
Journal of Hazardous Materials, 2011Co-Authors: Nicolas Perdrial, Nelson Rivera, Aaron Thompson, Peggy A Oday, Jon ChoroverAbstract:Abstract Prior work has shown that when silicaceous sediments are infused with caustic radioactive waste, Contaminant fate is tightly coupled to ensuing mineral weathering reactions. However, the effects of local aqueous geochemical conditions on these reactions are poorly studied. Thus, we varied Contaminant concentration and pCO2 during the weathering of previously uncontaminated Hanford sediments over 6 months and 1 year in a solution of caustic waste (pH 13, high ionic strength). Co-Contaminants Sr, Cs and I were added at “low” (Cs/Sr: 10−5 m; I: 10−7 m) and “high” (Cs/Sr: 10−3 m; I: 10−5 m) concentrations, and headspace was held at atmospheric or undetectable (
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final report caustic waste soil weathering reactions and their impacts on Trace Contaminant migration and sequestration
2006Co-Authors: Peggy A Oday, Jon Chorover, Karl T Mueller, R J SerneAbstract:The principal goal of this project was to assess the molecular nature and stability of radionuclide (137-Cs, 90-Sr, and 129-I) immobilization during weathering reactions in bulk Hanford sediments and their high surface area clay mineral constituents. We focused on the unique aqueous geochemical conditions that are representative of waste-impacted locations in the Hanford site vadose zone: high ionic strength, high pH and high Al concentrations. The specific objectives of the work were to (i) measure the coupling of clay mineral weathering and Contaminant uptake kinetics of Cs+, Sr2+ and I-; (ii) determine the molecular structure of Contaminant binding sites and their change with weathering time during and after exposure to synthetic tank waste leachate (STWL); (iii) establish the stability of neoformed weathering products and their sequestered Contaminants upon exposure of the solids to more “natural” soil solutions (i.e., after removal of the caustic waste source); and (iv) integrate macroscopic, microscopic and spectroscopic data to distinguish labile from non-labile Contaminant binding environments, including their dependence on system composition and weathering time. During this funding period, we completed a large set of bench-scale collaborative experiments and product characterization aimed at elucidating the coupling between mineral transformation reactions and Contaminant sequestration/stabilization. Our experiments more » included three representative Hanford sediments: course and fine sediments collected from the Hanford Formation and Ringold Silt, in addition to investigations with specimen clay minerals illite, vermiculite, smectite and kaolinite. These experiments combined macroscopic measurements of element release, Contaminant uptake and subsequent neoformed mineral dissolution behavior, with detailed studies of solid phase products using SEM and TEM microscopy, NMR, XAS and FTIR spectroscopy. Our studies have shown direct coupling between mineral transformation reactions and Contaminant sequestration/stabilization. « less
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caustic waste soil weathering reactions and their impacts on Trace Contaminant migration and sequestration
Other Information: PBD: 1 Jun 2003, 2003Co-Authors: Jon Chorover, Peggy A Oday, Karl T Mueller, Jeff R SerneAbstract:Waste produced during the production and purification of weapons-grade nuclear material is stored in underground tanks at the Hanford site in Washington state. Since their burial, many of the storage tanks have leaked caustic nuclear waste contaminated with radioactive Cs-137, Sr- 90, and I-129 into the surrounding soils. The effects on the natural soils of these particular radionuclides in a highly caustic solution are largely unknown, as are the transport properties. Recent work has shown that zeolite-type aluminosilicate phases form in clay mineral systems weathered under near-field exposure to Hanford-type nuclear waste. The transport and sequestration of Cs-137, Sr-90, and I-129 in the sediments is partially controlled by the cation adsorption-exchange properties of the parent clay minerals and these zeolitic neophases. This project seeks to isolate the effects of these new phases on Contaminant adsorption by identifying the Contaminant binding structures, assisting in the identification of neoformed phases, probing the kinetics of phase formation and Contaminant uptake, and investigating the mobility of these specific radionuclides in silicon-induced precipitates from synthetic tank waste representative of that at the Hanford site. In work at Penn State University, these objectives are being accomplished through the use of solid-state nuclear magnetic resonance (NMR) spectroscopy.
Juan Antonio Lopezramirez - One of the best experts on this subject based on the ideXlab platform.
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evaluation of a membrane bioreactor and nanofiltration for municipal wastewater reclamation Trace Contaminant control and fouling mitigation
Desalination, 2011Co-Authors: Kangmin Chon, Sarper Sarp, Juan Antonio LopezramirezAbstract:Abstract A membrane bioreactor (MBR) and nanofiltration (NF) membrane processes were developed for municipal wastewater reclamation, and their performances, in terms of Trace Contaminant control and fouling mitigation, were evaluated and designed to meet water quality criteria and minimize flux decline. The dissolved Contaminants in wastewater were poorly degraded by MBR but the microbial nitrification in MBR could greatly contribute to nitrogen removal in the MBR permeate through the addition of a NF membrane. Furthermore, most dissolved Contaminants were efficiently removed by the NF membrane. However, the NF membrane was ineffective in the removal of boron. The org-N/C molar ratio was inversely correlated to SUVA and directly corresponded to the 3D FEEM, structural analysis, and IR spectra of organic matter in raw and treated water, and desorbed foulants. The observations obtained from rigorous characterization revealed that the hydrophilic fractions, which were comprised of polysaccharides and amino groups, played a major role in fouling formation of the MBR–NF system. In addition, strong amide IR peak in the NF-base supported the notion that amino groups were primarily responsible for the fouling formation of the NF membrane relative to the polysaccharides groups.
Kangmin Chon - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of a membrane bioreactor and nanofiltration for municipal wastewater reclamation: Trace Contaminant control and fouling mitigation
Desalination, 2020Co-Authors: Kangmin Chon, Sarper Sarp, J.a. Lopez-ramirezAbstract:A membrane bioreactor (MBR) and nanofiltration (NF) membrane processes were developed for municipal wastewater reclamation, and their performances, in terms of Trace Contaminant control and fouling mitigation, were evaluated and designed to meet water quality criteria and minimize flux decline. The dissolved Contaminants in wastewater were poorly degraded by MBR but the microbial nitrification in MBR could greatly contribute to nitrogen removal in the MBR permeate through the addition of a NF membrane. Furthermore, most dissolved Contaminants were efficiently removed by the NF membrane. However, the NF membrane was ineffective in the removal of boron. The org-N/C molar ratio was inversely correlated to SUVA and directly corresponded to the 3D FEEM, structural analysis, and IR spectra of organic matter in raw and treated water, and desorbed foulants. The observations obtained from rigorous characterization revealed that the hydrophilic fractions, which were comprised of polysaccharides and amino groups, played a major role in fouling formation of the MBR-NF system. In addition, strong amide IR peak in the NF-base supported the notion that amino groups were primarily responsible for the fouling formation of the NF membrane relative to the polysaccharides groups. (C) 2011 Elsevier B.V. All rights reservedclose222
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evaluation of a membrane bioreactor and nanofiltration for municipal wastewater reclamation Trace Contaminant control and fouling mitigation
Desalination, 2011Co-Authors: Kangmin Chon, Sarper Sarp, Juan Antonio LopezramirezAbstract:Abstract A membrane bioreactor (MBR) and nanofiltration (NF) membrane processes were developed for municipal wastewater reclamation, and their performances, in terms of Trace Contaminant control and fouling mitigation, were evaluated and designed to meet water quality criteria and minimize flux decline. The dissolved Contaminants in wastewater were poorly degraded by MBR but the microbial nitrification in MBR could greatly contribute to nitrogen removal in the MBR permeate through the addition of a NF membrane. Furthermore, most dissolved Contaminants were efficiently removed by the NF membrane. However, the NF membrane was ineffective in the removal of boron. The org-N/C molar ratio was inversely correlated to SUVA and directly corresponded to the 3D FEEM, structural analysis, and IR spectra of organic matter in raw and treated water, and desorbed foulants. The observations obtained from rigorous characterization revealed that the hydrophilic fractions, which were comprised of polysaccharides and amino groups, played a major role in fouling formation of the MBR–NF system. In addition, strong amide IR peak in the NF-base supported the notion that amino groups were primarily responsible for the fouling formation of the NF membrane relative to the polysaccharides groups.
Andrea I Schafer - One of the best experts on this subject based on the ideXlab platform.
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inorganic Trace Contaminant removal from real brackish groundwater using electrodialysis
Separation and Purification Technology, 2017Co-Authors: Cristina Onorato, Andrea I Schafer, Laura BanasiakAbstract:Abstract The removal of inorganic Trace Contaminants from a real brackish groundwater from a remote Australian community using electrodialysis was investigated. Systematic investigation of applied voltage and solution pH was aimed to elucidate removal and deposition mechanisms in a complex water. A higher applied voltage enhanced removal of arsenic (V), boron, lithium, selenium (VI) and uranium. The removal of boron, lithium, sulfate, uranium, calcium, magnesium, strontium, zinc and selenium was pH dependent while the removal of bromide, chloride, fluoride and nitrate was pH independent. The precipitation of insoluble species at high pH and their complexation with other Contaminants resulted in membrane deposition in the form of scaling. This influenced system performance in regards to an increase in stack resistance and decrease in removal of total dissolved solids. The hydrated radius and strength of hydration shells played a less important role in the transport and removal of ions during electrodialysis of real water in comparison to other parameter such us ion concentration and solution pH. Results from this study showed that although electrodialysis is effective in the removal of Contaminants from real waters, consideration needs to be given to its long-term practical applicability in regards to membrane scaling.
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Removal of inorganic Trace Contaminants by electrodialysis in a remote Australian community
Desalination, 2009Co-Authors: Laura Banasiak, Andrea I SchaferAbstract:Water provision for developing countries is a critical issue as a vast number of lives are lost annually due to lack of access to safe drinking water. The presence and fate of inorganic Trace Contaminants is of particular concern. Trace inorganic Contaminants have been found in elevated concentrations in drinking waters supplied directly from brackish groundwaters in developing countries. Desalination and the removal of Trace inorganic Contaminants from bore water sources from a remote community in Australia using electrodialysis (ED) were investigated. The influence of applied voltage on the removal of the Trace Contaminants was evaluated. While the results from this study demonstrated that ED is an effectual method for the removal of total dissolved solids and a number of Trace inorganic Contaminants from brackish groundwaters to below drinking water guideline levels, the deposition of Trace Contaminants on the membranes (fouling) influenced the ED process in relation to ionic flux and the effectiveness of Trace Contaminant removal.
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adsorption and transport of Trace Contaminant estrone in nf ro membranes
Environmental Engineering Science, 2002Co-Authors: Long D Nghiem, Andrea I SchaferAbstract:Despite of their low concentration, the impact of steroid estrogens such as estrone, 17 α-estradiol, and ethinylestradiol are often more serious than other synthetic endocrine-disrupting chemicals (EDCs) because their endocrine-disrupting potency is much higher. Although their existence in waterways is of increasing concern, nanofiltration (NF) and reverse osmosis (RO) are likely to play an important role in removal of these compounds. This article describes the mechanisms involved in the retention of estrogen estrone using NF and RO. NF/RO membranes may adsorb Trace Contaminant estrone, which may result in an initially high retention. If the pore size of the membranes is larger than the estrone molecules, breakthrough can be observed when the membrane adsorptive sites are saturated. Although there is negligible effect of ionic strength on estrone adsorption by the membrane, it is strongly influenced by pH near the pKa value of estrone (10.4). Although static adsorption experiments give a linear adsorptio...
