The Experts below are selected from a list of 24 Experts worldwide ranked by ideXlab platform
Anh V Nguyen - One of the best experts on this subject based on the ideXlab platform.
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physical and chemical analysis of elemental sulfur formation during galena surface oxidation
Langmuir, 2011Co-Authors: Marc A Hampton, Chris Plackowski, Anh V NguyenAbstract:The surface oxidation of sulfide minerals, such as galena (PbS), in aqueous solutions is of critical importance in a number of applications. A comprehensive understanding of the formation of oxidation species at the galena surface is still lacking. Much controversy over the nature of these oxidation products exists. A number of oxidation pathways have been proposed, and experimental evidence for the formation of elemental sulfur, metal polySulfides, and metal-deficient Lead Sulfides in acidic conditions has been shown and argued. This paper provides further insight into the electrochemical behavior of galena at pH 4.5. Utilizing a novel experimental system that combines in situ electrochemical control and AC mode atomic force microscopy (AFM) surface imaging, the formation and growth of nanoscopic domains on the galena surface are detected and examined at anodic potentials. AFM phase images indicate that these domains have different material properties to the underlying galena. Continued oxidation results in nanoscopic pitting and the formation of microscopic surface domains, which are confirmed to be elemental sulfur by Raman spectroscopy. Further clarification of the presence of elemental sulfur is provided by Cryo-XPS. Polysulfide and metal-deficient sulfide could not be detected within this system.
Marc A Hampton - One of the best experts on this subject based on the ideXlab platform.
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physical and chemical analysis of elemental sulfur formation during galena surface oxidation
Langmuir, 2011Co-Authors: Marc A Hampton, Chris Plackowski, Anh V NguyenAbstract:The surface oxidation of sulfide minerals, such as galena (PbS), in aqueous solutions is of critical importance in a number of applications. A comprehensive understanding of the formation of oxidation species at the galena surface is still lacking. Much controversy over the nature of these oxidation products exists. A number of oxidation pathways have been proposed, and experimental evidence for the formation of elemental sulfur, metal polySulfides, and metal-deficient Lead Sulfides in acidic conditions has been shown and argued. This paper provides further insight into the electrochemical behavior of galena at pH 4.5. Utilizing a novel experimental system that combines in situ electrochemical control and AC mode atomic force microscopy (AFM) surface imaging, the formation and growth of nanoscopic domains on the galena surface are detected and examined at anodic potentials. AFM phase images indicate that these domains have different material properties to the underlying galena. Continued oxidation results in nanoscopic pitting and the formation of microscopic surface domains, which are confirmed to be elemental sulfur by Raman spectroscopy. Further clarification of the presence of elemental sulfur is provided by Cryo-XPS. Polysulfide and metal-deficient sulfide could not be detected within this system.
David N Harpp - One of the best experts on this subject based on the ideXlab platform.
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new methodologies fluorodemetalation of organogermanium tin and Lead compounds applications with organometallic Sulfides to produce highly active anions and spectroscopic evidence for pentavalent intermediates in substitution at tin
Journal of Organic Chemistry, 1990Co-Authors: Marc Gingras, T H Chan, David N HarppAbstract:The general concept of fluorodemetalation is illustrated with three novel methodologies. Fluoride ion smoothly demetalates organogermanium, -tin, and -Lead Sulfides under mild and neutral conditions to liberate active nucleophilic sulfur species. Eight different sulfur transfer agents derived from group IV are used to demonstrate fluorodemetalation. The reactions of fluorodeplumbylation and fluorodegermanylation are presented for the first time along with a discussion of their potential uses in chemistry
Chris Plackowski - One of the best experts on this subject based on the ideXlab platform.
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physical and chemical analysis of elemental sulfur formation during galena surface oxidation
Langmuir, 2011Co-Authors: Marc A Hampton, Chris Plackowski, Anh V NguyenAbstract:The surface oxidation of sulfide minerals, such as galena (PbS), in aqueous solutions is of critical importance in a number of applications. A comprehensive understanding of the formation of oxidation species at the galena surface is still lacking. Much controversy over the nature of these oxidation products exists. A number of oxidation pathways have been proposed, and experimental evidence for the formation of elemental sulfur, metal polySulfides, and metal-deficient Lead Sulfides in acidic conditions has been shown and argued. This paper provides further insight into the electrochemical behavior of galena at pH 4.5. Utilizing a novel experimental system that combines in situ electrochemical control and AC mode atomic force microscopy (AFM) surface imaging, the formation and growth of nanoscopic domains on the galena surface are detected and examined at anodic potentials. AFM phase images indicate that these domains have different material properties to the underlying galena. Continued oxidation results in nanoscopic pitting and the formation of microscopic surface domains, which are confirmed to be elemental sulfur by Raman spectroscopy. Further clarification of the presence of elemental sulfur is provided by Cryo-XPS. Polysulfide and metal-deficient sulfide could not be detected within this system.
Marc Gingras - One of the best experts on this subject based on the ideXlab platform.
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new methodologies fluorodemetalation of organogermanium tin and Lead compounds applications with organometallic Sulfides to produce highly active anions and spectroscopic evidence for pentavalent intermediates in substitution at tin
Journal of Organic Chemistry, 1990Co-Authors: Marc Gingras, T H Chan, David N HarppAbstract:The general concept of fluorodemetalation is illustrated with three novel methodologies. Fluoride ion smoothly demetalates organogermanium, -tin, and -Lead Sulfides under mild and neutral conditions to liberate active nucleophilic sulfur species. Eight different sulfur transfer agents derived from group IV are used to demonstrate fluorodemetalation. The reactions of fluorodeplumbylation and fluorodegermanylation are presented for the first time along with a discussion of their potential uses in chemistry