The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform
Gregory W Peterson - One of the best experts on this subject based on the ideXlab platform.
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Zirconium Hydroxide–Metal–Organic Framework Composites for Toxic Chemical Removal
2016Co-Authors: Gregory W Peterson, Joseph A. Rossin, Jared B. Decoste, Kato L. Killops, Matthew Browe, Erica Valdes, Paulette JonesAbstract:Composite materials comprising the metal–organic framework CuBTC (HKUST-1 or Cu3(BTC)2) and zirconium hydroxide were made to develop a material capable of broad spectrum toxic chemical removal. Materials were physically mixed at varying percentages, followed by pressing into pellets to set the structure. Mixtures were confirmed using powder X-ray diffraction, attenuated total reflectance–Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Nitrogen isotherm data were collected on the composite media, followed by breakthrough testing against ammonia, Cyanogen Chloride, and sulfur dioxide. All samples exhibited substantial porosity. As the percentage of CuBTC increased, ammonia performance increased while sulfur dioxide removal generally decreased. Cyanogen Chloride removal increased with increased CuBTC percentage under dry conditions, but failed to provide any significant removal under humid conditions. Adding triethylenediamine to the composites resulted in a substantial increase in Cyanogen Chloride removal capacity under humid conditions. In all, the composite structures resulted in some synergistic effects for ammonia and Cyanogen Chloride, with removal capacities higher than weighted averages based on performance of pure components. Data indicate that composites comprising CuBTC and zirconium hydroxide may be viable for broad spectrum toxic chemical filtration
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engineering uio 66 nh2 for toxic gas removal
Industrial & Engineering Chemistry Research, 2014Co-Authors: Gregory W Peterson, Jared B Decoste, Farzin Fatollahifard, David K BrittAbstract:The metal–organic framework UiO-66-NH2 was synthesized in a scaled batch of approximately 100 g. The material was then pressed into small pellets at pressures ranging from 5000 to 100000 psi to determine the effects on porosity and crystal structure. Nitrogen isotherm data and powder X-ray diffraction data indicate that the structure remains intact up to 25000 psi, with only a slight decrease in surface area. The structure exhibits significant degradation at pressures above 25000 psi. Subsequently, the powder was pressed at 5000 psi and then crushed and sieved into 20 × 40 mesh granules for evaluation against ammonia and Cyanogen Chloride in a breakthrough system simulating individual protection filters and respirator cartridges. The MOF showed capacity similar to that of a broad-spectrum carbon for both ammonia and Cyanogen Chloride; however, the breakthrough times, especially for Cyanogen Chloride, were dramatically reduced, likely as a result of mass-transfer limitations from the completely microporous...
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Engineering UiO-66-NH2 for Toxic Gas Removal
2014Co-Authors: Gregory W Peterson, Jared B. Decoste, Farzin Fatollahi-fard, David K BrittAbstract:The metal–organic framework UiO-66-NH2 was synthesized in a scaled batch of approximately 100 g. The material was then pressed into small pellets at pressures ranging from 5000 to 100000 psi to determine the effects on porosity and crystal structure. Nitrogen isotherm data and powder X-ray diffraction data indicate that the structure remains intact up to 25000 psi, with only a slight decrease in surface area. The structure exhibits significant degradation at pressures above 25000 psi. Subsequently, the powder was pressed at 5000 psi and then crushed and sieved into 20 × 40 mesh granules for evaluation against ammonia and Cyanogen Chloride in a breakthrough system simulating individual protection filters and respirator cartridges. The MOF showed capacity similar to that of a broad-spectrum carbon for both ammonia and Cyanogen Chloride; however, the breakthrough times, especially for Cyanogen Chloride, were dramatically reduced, likely as a result of mass-transfer limitations from the completely microporous MOF
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Evaluation of a robust, diimide-based, porous organic polymer (POP) as a high-capacity sorbent for representative chemical threats
Journal of Porous Materials, 2012Co-Authors: Gregory W Peterson, Paulette Jones, Omar K. Farha, Bryan Schindler, John Mahle, Joseph T. HuppAbstract:A previously described porous organic polymer (NU-POP-1) was evaluated against four representative chemical threats: ammonia, Cyanogen Chloride, sulfur dioxide, and octane. Ammonia, Cyanogen Chloride, and sulfur dioxide are examples of toxic industrial chemicals (TICs) spanning the range from highly basic to strong-acid forming substances, while octane is used to assess physical adsorption capacity. Experiments were carried out using a microbreakthrough test apparatus, which measures the adsorption capacity at saturation and gives an indication of the strength of adsorption. The NU-POP-1 material exhibited substantial removal capabilities against the majority of the toxic chemicals, with capacities as high as or better than an activated, impregnated carbon. The ability to remove the highly volatile toxic chemicals ammonia and Cyanogen Chloride was intriguing, as these chemicals typically require reactive moieities for removal. The present work presents a benchmark for toxic chemical removal, and future work will focus on incorporating functional groups targeting the toxic chemicals of interest.
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Enhanced Cyanogen Chloride Removal by the Reactive Zirconium Hydroxide Substrate
Industrial & Engineering Chemistry Research, 2010Co-Authors: Gregory W Peterson, George W. Wagner, Jennifer H. Keller, Joseph A. RossinAbstract:A novel microporous sorbent consisting of zirconium hydroxide impregnated with triethylenediamine (TEDA) was evaluated for the removal of Cyanogen Chloride. Breakthrough data were collected on packed beds, illustrating the efficacious nature of TEDA and the enhanced Cyanogen Chloride removal from the basic zirconium hydroxide structure. NMR and XPS analyses revealed the fate of Cyanogen Chloride, with inorganic Chloride byproducts deposited on the surface of the material and polymerized urea condensates physically adsorbed in the pore structure. The zirconium hydroxide media were found to provide significantly enhanced removal capabilities as compared to traditionally impregnated activated carbons, allowing for the development of respirators with reduced encumbrance.
David A Reckhow - One of the best experts on this subject based on the ideXlab platform.
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a rapid and simple analytical method for Cyanogen Chloride and Cyanogen bromide in drinking water
Water Research, 1993Co-Authors: David A ReckhowAbstract:Abstract A simple gas chromatographic method was developed for the determination of Cyanogen Chloride and Cyanogen bromide in drinking waters. Saturated headspace is injected directly onto a capillary column and the analytes are quantified by electron capture detection. Method detection limits are 0.04 and 0.2 μg/l for CNCl and CNBr, respectively. Effects of temperature and salt addition on analyte response were investigated. Other tests were conducted to determine the effects of sulfite and free chlorine on analyte stability. A concluding set of experiments showed the relationship between bromide concentration and Cyanogen halide speciation.
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A rapid and simple analytical method for Cyanogen Chloride and Cyanogen bromide in drinking water
Water Research, 1993Co-Authors: Yuefeng F. Xie, David A ReckhowAbstract:Abstract A simple gas chromatographic method was developed for the determination of Cyanogen Chloride and Cyanogen bromide in drinking waters. Saturated headspace is injected directly onto a capillary column and the analytes are quantified by electron capture detection. Method detection limits are 0.04 and 0.2 μg/l for CNCl and CNBr, respectively. Effects of temperature and salt addition on analyte response were investigated. Other tests were conducted to determine the effects of sulfite and free chlorine on analyte stability. A concluding set of experiments showed the relationship between bromide concentration and Cyanogen halide speciation.
Joseph A. Rossin - One of the best experts on this subject based on the ideXlab platform.
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Zirconium Hydroxide–Metal–Organic Framework Composites for Toxic Chemical Removal
2016Co-Authors: Gregory W Peterson, Joseph A. Rossin, Jared B. Decoste, Kato L. Killops, Matthew Browe, Erica Valdes, Paulette JonesAbstract:Composite materials comprising the metal–organic framework CuBTC (HKUST-1 or Cu3(BTC)2) and zirconium hydroxide were made to develop a material capable of broad spectrum toxic chemical removal. Materials were physically mixed at varying percentages, followed by pressing into pellets to set the structure. Mixtures were confirmed using powder X-ray diffraction, attenuated total reflectance–Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Nitrogen isotherm data were collected on the composite media, followed by breakthrough testing against ammonia, Cyanogen Chloride, and sulfur dioxide. All samples exhibited substantial porosity. As the percentage of CuBTC increased, ammonia performance increased while sulfur dioxide removal generally decreased. Cyanogen Chloride removal increased with increased CuBTC percentage under dry conditions, but failed to provide any significant removal under humid conditions. Adding triethylenediamine to the composites resulted in a substantial increase in Cyanogen Chloride removal capacity under humid conditions. In all, the composite structures resulted in some synergistic effects for ammonia and Cyanogen Chloride, with removal capacities higher than weighted averages based on performance of pure components. Data indicate that composites comprising CuBTC and zirconium hydroxide may be viable for broad spectrum toxic chemical filtration
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Enhanced Cyanogen Chloride Removal by the Reactive Zirconium Hydroxide Substrate
Industrial & Engineering Chemistry Research, 2010Co-Authors: Gregory W Peterson, George W. Wagner, Jennifer H. Keller, Joseph A. RossinAbstract:A novel microporous sorbent consisting of zirconium hydroxide impregnated with triethylenediamine (TEDA) was evaluated for the removal of Cyanogen Chloride. Breakthrough data were collected on packed beds, illustrating the efficacious nature of TEDA and the enhanced Cyanogen Chloride removal from the basic zirconium hydroxide structure. NMR and XPS analyses revealed the fate of Cyanogen Chloride, with inorganic Chloride byproducts deposited on the surface of the material and polymerized urea condensates physically adsorbed in the pore structure. The zirconium hydroxide media were found to provide significantly enhanced removal capabilities as compared to traditionally impregnated activated carbons, allowing for the development of respirators with reduced encumbrance.
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Role of TEDA as an Activated Carbon Impregnant for the Removal of Cyanogen Chloride from Air Streams: Synergistic Effect with Cu(II)
The Journal of Physical Chemistry C, 2010Co-Authors: John J. Mahle, Gregory W Peterson, Joseph A. Rossin, Bryan J. Schindler, Philip B. Smith, George W. WagnerAbstract:The hydrolysis and fate of Cyanogen Chloride (CK) in the presence of triethylenediamine (TEDA)—a widely used carbon impregnant—in aqueous and nonaqueous (acetonitrile) media has been determined. In the presence of water, anticipated TEDA substitution is not observed; rather, simple base-catalyzed (OH−) hydrolysis to cyanic acid (HOCN; unstable in water, decomposing to CO2 and NH3) is the major reaction, accompanied by a series of complex side reactions (not involving TEDA) to form several persistent compounds. Thus, the role of TEDA, in the presence of water, is primarily a source of OH−. CK substitution at TEDA is observed in acetonitrile, again forming several complex, but quite different, species. Studies examining the removal of CK from humidified air streams by carbon impregnated with TEDA and/or basic Cu2+ (another common carbon impregnant) are consistent with simple hydrolysis being the major CK-removal mechanism; no TEDA substitution is observed in the presence of humidity/water. Considering the r...
Husam M. Abu-soud - One of the best experts on this subject based on the ideXlab platform.
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Melatonin prevents hypochlorous acid‐mediated cyanocobalamin destruction and Cyanogen Chloride generation
Journal of Pineal Research, 2018Co-Authors: Roohi Jeelani, Dhiman Maitra, Charalampos Chatzicharalampous, Syed Najeemuddin, Robert T. Morris, Husam M. Abu-soudAbstract:Hypochlorous acid (HOCl) is a potent cytotoxic oxidant generated by the enzyme myeloperoxidase (MPO) in the presence of hydrogen peroxide (H2 O2 ) and Chloride (Cl- ). Elevated levels of HOCl play an important role in various pathological conditions through oxidative modification of several biomolecules. Recently, we have highlighted the ability of HOCl to mediate the destruction of the metal-ion derivatives of tetrapyrrole macrocyclic rings such as hemoproteins and vitamin B12 (VB12 ) derivatives. Destruction of cyanocobalamin, a common pharmacological form of VB12 mediated by HOCl, results in the generation of toxic molecular products such as chlorinated derivatives, corrin ring cleavage products, the toxic blood agents cyanide (CN- ) and Cyanogen Chloride (CNCl), and redox-active free cobalt. Here, we show that melatonin prevents HOCl-mediated cyanocobalamin destruction, using a combination of UV-Vis spectrophotometry, high-performance liquid chromatography analysis, and colorimetric CNCl assay. Identification of several melatonin oxidation products suggests that the protective role of melatonin against HOCl-mediated cyanocobalamin destruction and subsequent CNCl generation is at the expense of melatonin oxidation. Collectively, this work highlights that, in addition to acting as an antioxidant and as a MPO inhibitor, melatonin can also prevent VB12 deficiency in inflammatory conditions such as cardiovascular and neurodegenerative diseases, among many others.
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The reaction of HOCl and cyanocobalamin: Corrin destruction and the liberation of Cyanogen Chloride
Free radical biology & medicine, 2011Co-Authors: Husam M. Abu-soud, Dhiman Maitra, Jaeman Byun, Carlos Eduardo A. Souza, Jashoman Banerjee, Ghassan M. Saed, Michael P. Diamond, Peter R. Andreana, Subramaniam PennathurAbstract:Abstract Overproduction of hypochlorous acid (HOCl) has been associated with the development of a variety of disorders such as inflammation, heart disease, pulmonary fibrosis, and cancer through its ability to modify various biomolecules. HOCl is a potent oxidant generated by the myeloperoxidase–hydrogen peroxide–Chloride system. Recently, we have provided evidence to support the important link between higher levels of HOCl and heme destruction and free iron release from hemoglobin and RBCs. Our current findings extend this work and show the ability of HOCl to mediate the destruction of metal-ion derivatives of tetrapyrrole macrocyclic rings, such as cyanocobalamin (Cobl), a common pharmacological form of vitamin B12. Cyanocobalamin is a water-soluble vitamin that plays an essential role as an enzyme cofactor and antioxidant, modulating nucleic acid metabolism and gene regulation. It is widely used as a therapeutic agent and supplement, because of its efficacy and stability. In this report, we demonstrate that although Cobl can be an excellent antioxidant, exposure to high levels of HOCl can overcome the beneficial effects of Cobl and generate proinflammatory reaction products. Our rapid kinetic, HPLC, and mass spectrometric analyses showed that HOCl can mediate corrin ring destruction and liberate Cyanogen Chloride (CNCl) through a mechanism that initially involves α-axial ligand replacement in Cobl to form a chlorinated derivative, hydrolysis, and cleavage of the phosphonucleotide moiety. Additionally, it can liberate free Co, which can perpetuate metal-ion-induced oxidant stress. Taken together, these results are the first report of the generation of toxic molecular products through the interaction of Cobl with HOCl.
George W. Wagner - One of the best experts on this subject based on the ideXlab platform.
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Enhanced Cyanogen Chloride Removal by the Reactive Zirconium Hydroxide Substrate
Industrial & Engineering Chemistry Research, 2010Co-Authors: Gregory W Peterson, George W. Wagner, Jennifer H. Keller, Joseph A. RossinAbstract:A novel microporous sorbent consisting of zirconium hydroxide impregnated with triethylenediamine (TEDA) was evaluated for the removal of Cyanogen Chloride. Breakthrough data were collected on packed beds, illustrating the efficacious nature of TEDA and the enhanced Cyanogen Chloride removal from the basic zirconium hydroxide structure. NMR and XPS analyses revealed the fate of Cyanogen Chloride, with inorganic Chloride byproducts deposited on the surface of the material and polymerized urea condensates physically adsorbed in the pore structure. The zirconium hydroxide media were found to provide significantly enhanced removal capabilities as compared to traditionally impregnated activated carbons, allowing for the development of respirators with reduced encumbrance.
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Role of TEDA as an Activated Carbon Impregnant for the Removal of Cyanogen Chloride from Air Streams: Synergistic Effect with Cu(II)
The Journal of Physical Chemistry C, 2010Co-Authors: John J. Mahle, Gregory W Peterson, Joseph A. Rossin, Bryan J. Schindler, Philip B. Smith, George W. WagnerAbstract:The hydrolysis and fate of Cyanogen Chloride (CK) in the presence of triethylenediamine (TEDA)—a widely used carbon impregnant—in aqueous and nonaqueous (acetonitrile) media has been determined. In the presence of water, anticipated TEDA substitution is not observed; rather, simple base-catalyzed (OH−) hydrolysis to cyanic acid (HOCN; unstable in water, decomposing to CO2 and NH3) is the major reaction, accompanied by a series of complex side reactions (not involving TEDA) to form several persistent compounds. Thus, the role of TEDA, in the presence of water, is primarily a source of OH−. CK substitution at TEDA is observed in acetonitrile, again forming several complex, but quite different, species. Studies examining the removal of CK from humidified air streams by carbon impregnated with TEDA and/or basic Cu2+ (another common carbon impregnant) are consistent with simple hydrolysis being the major CK-removal mechanism; no TEDA substitution is observed in the presence of humidity/water. Considering the r...
