The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform
Dongqiang Zhu - One of the best experts on this subject based on the ideXlab platform.
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Surface quinone-induced formation of aqueous reactive sulfur species controls pine wood biochar-mediated reductive dechlorination of Hexachloroethane by sulfide
Environmental science. Processes & impacts, 2020Co-Authors: Shujun Yin, Chenhui Wei, Dongqiang ZhuAbstract:Understanding the mechanisms controlling the redox transformation of organic contaminants mediated by biochar is of great significance for application of biochar in remediation of contaminated soils and sediments. Here we investigated the mediation effect of a pine wood-derived biochar (P-char) in comparison with multiwalled carbon nanotubes (MCNTs) and graphite on the reductive dechlorination of Hexachloroethane by sulfide. Upon normalization of the mediator's surface area, the reduction rate of Hexachloroethane follows an order of P-char < MCNTs < graphite. Aqueous polysulfides and polysulfide free radicals were readily produced by reacting sulfide only with P-char, and the supernatant separated from the reaction system could account for 83.4% of the pseudo-kinetic rate constant of Hexachloroethane mediated by P-char. In contrast, MCNTs and graphite had weak abilities to produce reactive sulfur species, and the supernatant exhibited very low reduction capability (
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surface quinone induced formation of aqueous reactive sulfur species controls pine wood biochar mediated reductive dechlorination of Hexachloroethane by sulfide
Environmental Science: Processes & Impacts, 2020Co-Authors: Shujun Yin, Chenhui Wei, Dongqiang ZhuAbstract:Understanding the mechanisms controlling the redox transformation of organic contaminants mediated by biochar is of great significance for application of biochar in remediation of contaminated soils and sediments. Here we investigated the mediation effect of a pine wood-derived biochar (P-char) in comparison with multiwalled carbon nanotubes (MCNTs) and graphite on the reductive dechlorination of Hexachloroethane by sulfide. Upon normalization of the mediator's surface area, the reduction rate of Hexachloroethane follows an order of P-char < MCNTs < graphite. Aqueous polysulfides and polysulfide free radicals were readily produced by reacting sulfide only with P-char, and the supernatant separated from the reaction system could account for 83.4% of the pseudo-kinetic rate constant of Hexachloroethane mediated by P-char. In contrast, MCNTs and graphite had weak abilities to produce reactive sulfur species, and the supernatant exhibited very low reduction capability (<20.7%) of Hexachloroethane. Electron paramagnetic resonance (EPR) analysis demonstrated that the surface quinone moieties on P-char induced the formation of polysulfides and polysulfide free radicals from sulfide by serving as one-electron acceptors. Consistently, polysulfides prepared by reacting elemental sulfur with sulfide showed much stronger reducing capability compared to sulfide. Thus, the mediation effect of P-char was dominantly attributed to the surface quinone-induced formation of reactive reducing sulfur species, whereas the mediation effect of MCNTs and graphite mainly stemmed from the enhanced electron transfer by the graphitized carbon. These results showed for the first time that surface quinone-induced formation of aqueous reactive sulfur species could control biochar-mediated reductive dechlorination of chloroorganic contaminants by sulfides.
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Reductive dechlorination of Hexachloroethane by sulfide in aqueous solutions mediated by graphene oxide and carbon nanotubes
Carbon, 2014Co-Authors: Yong Guo, Wei Chen, Dongqiang ZhuAbstract:Abstract The main objective of this study was to test the capability of CNMs to mediate the reductive dechlorination of chlorinated aliphatic hydrocarbons. We herein investigated the mediation effects of graphene oxide (GO) and multi-walled carbon nanotubes (CNT) on the reductive dechlorination of Hexachloroethane by sodium sulfide in aqueous solutions (pH buffered). The presence of 10 mg/L CNT or GO enhanced the observed pseudo-first-order rate constant ( k obs ) of the reaction by a factor of 2 and 4, respectively; the enhancement effects were significantly greater than that of a soil humic acid (20 mg C/L). The strong enhancement effects of the test CNMs were attributable to the facilitated electron transfer by the graphitic surfaces and particularly to the activation of C–Cl bonds of Hexachloroethane by the zigzag carbon atoms at the edges and defects of the carbon nanomaterials. Additionally, changes of pH and the presence of dissolved humic acid could significantly affect the CNT- and GO-mediated reactions. The reaction rate was markedly accelerated by the increase of pH, but was suppressed by the coexisting dissolved humic acid. The findings imply that CNMs have the potential to enhance reductive dechlorination of relatively recalcitrant contaminants, such as chlorinated aliphatic hydrocarbons, in natural aquatic environments.
Shujun Yin - One of the best experts on this subject based on the ideXlab platform.
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Surface quinone-induced formation of aqueous reactive sulfur species controls pine wood biochar-mediated reductive dechlorination of Hexachloroethane by sulfide
Environmental science. Processes & impacts, 2020Co-Authors: Shujun Yin, Chenhui Wei, Dongqiang ZhuAbstract:Understanding the mechanisms controlling the redox transformation of organic contaminants mediated by biochar is of great significance for application of biochar in remediation of contaminated soils and sediments. Here we investigated the mediation effect of a pine wood-derived biochar (P-char) in comparison with multiwalled carbon nanotubes (MCNTs) and graphite on the reductive dechlorination of Hexachloroethane by sulfide. Upon normalization of the mediator's surface area, the reduction rate of Hexachloroethane follows an order of P-char < MCNTs < graphite. Aqueous polysulfides and polysulfide free radicals were readily produced by reacting sulfide only with P-char, and the supernatant separated from the reaction system could account for 83.4% of the pseudo-kinetic rate constant of Hexachloroethane mediated by P-char. In contrast, MCNTs and graphite had weak abilities to produce reactive sulfur species, and the supernatant exhibited very low reduction capability (
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surface quinone induced formation of aqueous reactive sulfur species controls pine wood biochar mediated reductive dechlorination of Hexachloroethane by sulfide
Environmental Science: Processes & Impacts, 2020Co-Authors: Shujun Yin, Chenhui Wei, Dongqiang ZhuAbstract:Understanding the mechanisms controlling the redox transformation of organic contaminants mediated by biochar is of great significance for application of biochar in remediation of contaminated soils and sediments. Here we investigated the mediation effect of a pine wood-derived biochar (P-char) in comparison with multiwalled carbon nanotubes (MCNTs) and graphite on the reductive dechlorination of Hexachloroethane by sulfide. Upon normalization of the mediator's surface area, the reduction rate of Hexachloroethane follows an order of P-char < MCNTs < graphite. Aqueous polysulfides and polysulfide free radicals were readily produced by reacting sulfide only with P-char, and the supernatant separated from the reaction system could account for 83.4% of the pseudo-kinetic rate constant of Hexachloroethane mediated by P-char. In contrast, MCNTs and graphite had weak abilities to produce reactive sulfur species, and the supernatant exhibited very low reduction capability (<20.7%) of Hexachloroethane. Electron paramagnetic resonance (EPR) analysis demonstrated that the surface quinone moieties on P-char induced the formation of polysulfides and polysulfide free radicals from sulfide by serving as one-electron acceptors. Consistently, polysulfides prepared by reacting elemental sulfur with sulfide showed much stronger reducing capability compared to sulfide. Thus, the mediation effect of P-char was dominantly attributed to the surface quinone-induced formation of reactive reducing sulfur species, whereas the mediation effect of MCNTs and graphite mainly stemmed from the enhanced electron transfer by the graphitized carbon. These results showed for the first time that surface quinone-induced formation of aqueous reactive sulfur species could control biochar-mediated reductive dechlorination of chloroorganic contaminants by sulfides.
Chenhui Wei - One of the best experts on this subject based on the ideXlab platform.
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Surface quinone-induced formation of aqueous reactive sulfur species controls pine wood biochar-mediated reductive dechlorination of Hexachloroethane by sulfide
Environmental science. Processes & impacts, 2020Co-Authors: Shujun Yin, Chenhui Wei, Dongqiang ZhuAbstract:Understanding the mechanisms controlling the redox transformation of organic contaminants mediated by biochar is of great significance for application of biochar in remediation of contaminated soils and sediments. Here we investigated the mediation effect of a pine wood-derived biochar (P-char) in comparison with multiwalled carbon nanotubes (MCNTs) and graphite on the reductive dechlorination of Hexachloroethane by sulfide. Upon normalization of the mediator's surface area, the reduction rate of Hexachloroethane follows an order of P-char < MCNTs < graphite. Aqueous polysulfides and polysulfide free radicals were readily produced by reacting sulfide only with P-char, and the supernatant separated from the reaction system could account for 83.4% of the pseudo-kinetic rate constant of Hexachloroethane mediated by P-char. In contrast, MCNTs and graphite had weak abilities to produce reactive sulfur species, and the supernatant exhibited very low reduction capability (
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surface quinone induced formation of aqueous reactive sulfur species controls pine wood biochar mediated reductive dechlorination of Hexachloroethane by sulfide
Environmental Science: Processes & Impacts, 2020Co-Authors: Shujun Yin, Chenhui Wei, Dongqiang ZhuAbstract:Understanding the mechanisms controlling the redox transformation of organic contaminants mediated by biochar is of great significance for application of biochar in remediation of contaminated soils and sediments. Here we investigated the mediation effect of a pine wood-derived biochar (P-char) in comparison with multiwalled carbon nanotubes (MCNTs) and graphite on the reductive dechlorination of Hexachloroethane by sulfide. Upon normalization of the mediator's surface area, the reduction rate of Hexachloroethane follows an order of P-char < MCNTs < graphite. Aqueous polysulfides and polysulfide free radicals were readily produced by reacting sulfide only with P-char, and the supernatant separated from the reaction system could account for 83.4% of the pseudo-kinetic rate constant of Hexachloroethane mediated by P-char. In contrast, MCNTs and graphite had weak abilities to produce reactive sulfur species, and the supernatant exhibited very low reduction capability (<20.7%) of Hexachloroethane. Electron paramagnetic resonance (EPR) analysis demonstrated that the surface quinone moieties on P-char induced the formation of polysulfides and polysulfide free radicals from sulfide by serving as one-electron acceptors. Consistently, polysulfides prepared by reacting elemental sulfur with sulfide showed much stronger reducing capability compared to sulfide. Thus, the mediation effect of P-char was dominantly attributed to the surface quinone-induced formation of reactive reducing sulfur species, whereas the mediation effect of MCNTs and graphite mainly stemmed from the enhanced electron transfer by the graphitized carbon. These results showed for the first time that surface quinone-induced formation of aqueous reactive sulfur species could control biochar-mediated reductive dechlorination of chloroorganic contaminants by sulfides.
Hans Marchner - One of the best experts on this subject based on the ideXlab platform.
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mutagenicity testing of condensates of smoke from titanium dioxide Hexachloroethane and zinc Hexachloroethane pyrotechnic mixtures
Mutation Research\ genetic Toxicology, 1991Co-Authors: Nils Karlsson, Ingrid Fängmark, Inger Häggqvist, Britt Karlsson, Lars Rittfeldt, Hans MarchnerAbstract:Condensates of smoke from titanium dioxide/Hexachloroethane and zinc/Hexachloroethane pyrotechnic mixtures were investigated for their potential to produce genetic damage in the tester strains TA98, TA100, TA1535 and TA1537 of Salmonella typhimurium and in the mouse bone marrow micronucleus assay. Both smoke condensates contained several chlorinated hydrocarbons among which tetrachloroethylene, Hexachloroethane, hexachlorobutadiene and hexachlorobenzene were identified by GC/MS. Condensate of smoke from titanium dioxide/Hexachloroethane showed a dose-related positive response in the Salmonella assay with strains TA98 and TA100 in the absence of metabolic activation from rat liver S9 fraction. Both smoke condensates were negative in the micronucleus assay but produced a small but significant depression of erythropoietic activity. The results indicate that smoke condensate from titanium dioxide/Hexachloroethane mixtures contains unidentified compound(s) that may be considered mutagenic in the Salmonella assay.
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Mutagenicity testing of condensates of smoke from titanium dioxide/Hexachloroethane and zinc/Hexachloroethane pyrotechnic mixtures.
Mutation research, 1991Co-Authors: Nils Karlsson, Ingrid Fängmark, Inger Häggqvist, Britt Karlsson, Lars Rittfeldt, Hans MarchnerAbstract:Condensates of smoke from titanium dioxide/Hexachloroethane and zinc/Hexachloroethane pyrotechnic mixtures were investigated for their potential to produce genetic damage in the tester strains TA98, TA100, TA1535 and TA1537 of Salmonella typhimurium and in the mouse bone marrow micronucleus assay. Both smoke condensates contained several chlorinated hydrocarbons among which tetrachloroethylene, Hexachloroethane, hexachlorobutadiene and hexachlorobenzene were identified by GC/MS. Condensate of smoke from titanium dioxide/Hexachloroethane showed a dose-related positive response in the Salmonella assay with strains TA98 and TA100 in the absence of metabolic activation from rat liver S9 fraction. Both smoke condensates were negative in the micronucleus assay but produced a small but significant depression of erythropoietic activity. The results indicate that smoke condensate from titanium dioxide/Hexachloroethane mixtures contains unidentified compound(s) that may be considered mutagenic in the Salmonella assay.
Nils Karlsson - One of the best experts on this subject based on the ideXlab platform.
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mutagenicity testing of condensates of smoke from titanium dioxide Hexachloroethane and zinc Hexachloroethane pyrotechnic mixtures
Mutation Research\ genetic Toxicology, 1991Co-Authors: Nils Karlsson, Ingrid Fängmark, Inger Häggqvist, Britt Karlsson, Lars Rittfeldt, Hans MarchnerAbstract:Condensates of smoke from titanium dioxide/Hexachloroethane and zinc/Hexachloroethane pyrotechnic mixtures were investigated for their potential to produce genetic damage in the tester strains TA98, TA100, TA1535 and TA1537 of Salmonella typhimurium and in the mouse bone marrow micronucleus assay. Both smoke condensates contained several chlorinated hydrocarbons among which tetrachloroethylene, Hexachloroethane, hexachlorobutadiene and hexachlorobenzene were identified by GC/MS. Condensate of smoke from titanium dioxide/Hexachloroethane showed a dose-related positive response in the Salmonella assay with strains TA98 and TA100 in the absence of metabolic activation from rat liver S9 fraction. Both smoke condensates were negative in the micronucleus assay but produced a small but significant depression of erythropoietic activity. The results indicate that smoke condensate from titanium dioxide/Hexachloroethane mixtures contains unidentified compound(s) that may be considered mutagenic in the Salmonella assay.
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Mutagenicity testing of condensates of smoke from titanium dioxide/Hexachloroethane and zinc/Hexachloroethane pyrotechnic mixtures.
Mutation research, 1991Co-Authors: Nils Karlsson, Ingrid Fängmark, Inger Häggqvist, Britt Karlsson, Lars Rittfeldt, Hans MarchnerAbstract:Condensates of smoke from titanium dioxide/Hexachloroethane and zinc/Hexachloroethane pyrotechnic mixtures were investigated for their potential to produce genetic damage in the tester strains TA98, TA100, TA1535 and TA1537 of Salmonella typhimurium and in the mouse bone marrow micronucleus assay. Both smoke condensates contained several chlorinated hydrocarbons among which tetrachloroethylene, Hexachloroethane, hexachlorobutadiene and hexachlorobenzene were identified by GC/MS. Condensate of smoke from titanium dioxide/Hexachloroethane showed a dose-related positive response in the Salmonella assay with strains TA98 and TA100 in the absence of metabolic activation from rat liver S9 fraction. Both smoke condensates were negative in the micronucleus assay but produced a small but significant depression of erythropoietic activity. The results indicate that smoke condensate from titanium dioxide/Hexachloroethane mixtures contains unidentified compound(s) that may be considered mutagenic in the Salmonella assay.
