The Experts below are selected from a list of 260307 Experts worldwide ranked by ideXlab platform
Mohsen Mehrabi - One of the best experts on this subject based on the ideXlab platform.
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surface structural alteration of multi walled carbon nanotubes decorated by nickel nanoparticles based on laser ablation Chemical Reduction methods to enhance hydrogen storage properties
2019Co-Authors: Mohsen Mehrabi, Parviz Parvin, A Reyhani, S Z MortazaviAbstract:Abstract The catalytic effect of nickel is addressed to decorate the multi-walled carbon nanotubes for the purpose of hydrogen storage. The hydrogen sorption/desorption are investigated using the volumetric technique. Nickel nanoparticles are distributed on the surface of nanotubes using the laser ablation/Chemical Reduction treatments. The hydrogen uptake is elevated at higher nickel population up to a certain value and then experiences a significant drop for larger nickel content. The laser treatment is accompanied by the induced pores around nanotubes. This gives rise to the creation of the larger pores at higher laser doses leading to decrease the hydrogen trapping. Despite the pore size distribution strongly alters during both synthesis methods, however the abundance of small pore size in laser treatments is relatively higher than the that of the other technique. In comparison, the laser ablation demonstrates a relatively smaller desorption temperature against Chemical one, mainly owing to the formation of larger pore size/volume. Generally, the hydrogen trapping efficiently takes place in the laser treated samples against Chemical Reduction method. The highest value of hydrogen storage ∼1% (0.6% weight) is corresponding to 12.3% (13% weight) of nickel loading via the laser ablation (Chemical Reduction).
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hydrogen storage in multi walled carbon nanotubes decorated with palladium nanoparticles using laser ablation Chemical Reduction methods
2017Co-Authors: Mohsen Mehrabi, Parviz Parvin, A Reyhani, S Z MortazaviAbstract:Hydrogen storage properties of multi-walled carbon nanotubes (MWCNTs) decorated by palladium nanoparticles (Pd NPs) are investigated using laser ablation and Chemical Reduction methods, revealing great differences between the two techniques. In the case of laser ablation, the hydrogen uptake is elevated with the Pd content up to a certain value and then undergoes a notable drop, whereas the hydrogen content linearly scales up with the Pd loading during the Chemical Reduction method. When the Pd loading is low, the storage capacity of the laser treated samples is higher than those decorated via the other technique of interest. During laser ablation, the larger Pd content is accompanied by plentiful pore formation, leading to larger pore sizes at higher doses, which seriously reduces the hydrogen uptake. Moreover, the desorption temperature of hydrogen notably increases in terms of Pd loading. In comparison, the laser ablation method undergoes a relatively smaller desorption temperature, mainly due to the larger pore size/volume.
S Z Mortazavi - One of the best experts on this subject based on the ideXlab platform.
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surface structural alteration of multi walled carbon nanotubes decorated by nickel nanoparticles based on laser ablation Chemical Reduction methods to enhance hydrogen storage properties
2019Co-Authors: Mohsen Mehrabi, Parviz Parvin, A Reyhani, S Z MortazaviAbstract:Abstract The catalytic effect of nickel is addressed to decorate the multi-walled carbon nanotubes for the purpose of hydrogen storage. The hydrogen sorption/desorption are investigated using the volumetric technique. Nickel nanoparticles are distributed on the surface of nanotubes using the laser ablation/Chemical Reduction treatments. The hydrogen uptake is elevated at higher nickel population up to a certain value and then experiences a significant drop for larger nickel content. The laser treatment is accompanied by the induced pores around nanotubes. This gives rise to the creation of the larger pores at higher laser doses leading to decrease the hydrogen trapping. Despite the pore size distribution strongly alters during both synthesis methods, however the abundance of small pore size in laser treatments is relatively higher than the that of the other technique. In comparison, the laser ablation demonstrates a relatively smaller desorption temperature against Chemical one, mainly owing to the formation of larger pore size/volume. Generally, the hydrogen trapping efficiently takes place in the laser treated samples against Chemical Reduction method. The highest value of hydrogen storage ∼1% (0.6% weight) is corresponding to 12.3% (13% weight) of nickel loading via the laser ablation (Chemical Reduction).
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hydrogen storage in multi walled carbon nanotubes decorated with palladium nanoparticles using laser ablation Chemical Reduction methods
2017Co-Authors: Mohsen Mehrabi, Parviz Parvin, A Reyhani, S Z MortazaviAbstract:Hydrogen storage properties of multi-walled carbon nanotubes (MWCNTs) decorated by palladium nanoparticles (Pd NPs) are investigated using laser ablation and Chemical Reduction methods, revealing great differences between the two techniques. In the case of laser ablation, the hydrogen uptake is elevated with the Pd content up to a certain value and then undergoes a notable drop, whereas the hydrogen content linearly scales up with the Pd loading during the Chemical Reduction method. When the Pd loading is low, the storage capacity of the laser treated samples is higher than those decorated via the other technique of interest. During laser ablation, the larger Pd content is accompanied by plentiful pore formation, leading to larger pore sizes at higher doses, which seriously reduces the hydrogen uptake. Moreover, the desorption temperature of hydrogen notably increases in terms of Pd loading. In comparison, the laser ablation method undergoes a relatively smaller desorption temperature, mainly due to the larger pore size/volume.
Christophe Mouvet - One of the best experts on this subject based on the ideXlab platform.
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laboratory study on the mobility of chlordecone and seven of its transformation products formed by Chemical Reduction in nitisol lysimeters of a banana plantation in martinique french caribbean
2020Co-Authors: Patrick Ollivier, Sébastien Bristeau, Jeremy Engevin, Christophe MouvetAbstract:Abstract The contamination by chlordecone (CLD) of soils and water in the French Caribbean (FC) has major environmental and human health impacts. In Situ Chemical Reduction (ISCR) is a promising method to degrade CLD but it generates transformation products (TPs). Here, the fate and transport of CLD and its TPs have been studied using three lysimeters, 65–70 cm-long and 20 cm in diameter, collected from a CLD contaminated nitisol in the FC. A simulated ISCR remediation process (Sim-ISCR) was applied to the top 15 cm layer. An equivalent of 9.8 years of effective rainfall was simulated during the 451 days of the experiments. CLD and seven TPs were analyzed in soils, soil pore waters and outflow waters of the lysimeters before and after the Sim-ISCR. CLD concentration in the soil pore waters increases with depth. In the Sim-ISCR treated layer, the CLD contamination was lowered by 41 to 47% in the soil and by 48 to 73% in the soil pore water. In the lysimeters outflow, however, the CLD concentration was lowered by only 13 to 25%, the flux of CLD from the untreated 50–55 cm of the profile concealing much of the beneficial impact of treating the top 15 cm. Remediating by ISCR the topsoil only will therefore not be sufficient for preventing further CLD contamination of the underlying groundwater. Sim-ISCR generated 5-hydroCLD in soils and waters and, to a much lesser extent, a trihydroCLD, a tetrahydroCLD, a pentahydroCLD and a heptahydroCLD. 5-hydroCLD is more mobile than CLD, but it still interacts strongly with the soil. The 5-hydroCLD values measured in the outflow were up to a factor of 4.4 lower than in the treated soil pore waters, indicating some natural attenuation.
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Physico-Chemical and agronomic results of soil remediation by In Situ Chemical Reduction applied to a chlordecone-contaminated nitisol at plot scale in a French Caribbean banana plantation
2020Co-Authors: Christophe Mouvet, Sébastien Bristeau, Bastien Collet, Jean-marie Gaude, Luc Rangon, Mathlide Senergues, Magalie Lesueur-jannoyer, Alexandra Jestin, Jennifer Hellal, Thierry WoignierAbstract:The In Situ Chemical Reduction (ISCR) process was tested in a nitisol in a French Caribbean banana plantation using five different soil amendments. The addition of 2.8% or 4.0% of Zero Valent Iron (ZVI; dw/dw, 2 different trial plots) in the 0–40-cm soil layer lowered the initial chlordecone (CLD) concentration by up to 74% or 69% in 37 days or 94 days, with 75% of the decrease achieved after only 21 or 24 days of treatment depending on the trial plot. The addition of commercially available Daramend® was also tested by applying the 6% dose (dw/dw) recommended by the manufacturer and using either the regular alfalfa-based product or a bagasse-based product specifically formulated for the study. Both significantly lowered CLD concentrations, but to a lesser extent than with the ZVI-only amendment. A bagasse-ZVI mixture prepared on site produced results slightly better than the two Daramend®. The percentage decreases in CLD concentrations were correlated with the negative redox potentials achieved. In all the trial plots, dechlorinated transformation products appeared in the soil and soil water as the CLD concentrations decreased, with H atoms replacing up to 4 and 7 of the 10 Cl atoms, respectively. None of these degradation products appeared to accumulate in the soil or soil water during the treatment. Instead, the reverse occurred, with an overall downward trend in their concentrations over time. The effects of ISCR treatment on agronomic and human health–related parameters were measured in three different crops. The radishes produced with some treatments were visually of lower quality or smaller in size than those grown in the control plots. Lower yields were observed for the cucumbers and sweet potatoes grown after applying the bagasse-based amendments. Mortality among cucumber seedlings was observed after treatment with ZVI only. Simple operational solutions should suffice to remedy these negative agronomic effects. As regards human health–related effects, the CLD concentrations in radishes grown with three of the amendments were significantly lower than in the two control plots and well below the maximum residue level (MRL), which was substantially exceeded in the radishes grown on untreated soil. For cucumbers, the treatments with regular Daramend® and with a local bagasse-ZVI mixture produced fruits with CLD below the MRL and also below the concentrations in one of the two control plots. As for the sweet potatoes, adding a bagasse-ZVI mixture had a significant positive effect by decreasing contamination below the levels in the two control plots and below the MRL.
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Remediation by Chemical Reduction in laboratory mesocosms of three chlordecone-contaminated tropical soils
2017Co-Authors: Christophe Mouvet, Dominique Breeze, Marie Christine Dictor, Sébastien Bristeau, Anne MercierAbstract:Chlordecone (CLD), a highly persistent organochlorine pesticide commonly encountered in French West Indies (FWI) agricultural soils, represents a major source of contamination of FWI ecosystems. The potential of Chemical Reduction for remediation of CLD-contaminated soil has been investigated in laboratory pilot-scale 80 kg mesocosms for andosol, ferralsol, and nitisol from FWI banana plantations. Six cycles consisting of a 3-week reducing phase followed by a 1-week oxidizing phase were applied, with 2 % (dw/dw) Daramend® (organic plant matter fortified with zero valent iron) added at the start of each cycle. Complementary amendments of zero valent iron and zinc (total of 3 % dw/dw) were added at the start of the first three cycles. After the 6-month treatment, the CLD soil concentration was lowered by 74 % in nitisol, 71 % in ferralsol, and 22 % in andosol. Eleven CLD-dechlorinated transformation products, from mono- to penta-dechlorinated, were identified. None of them accumulated over the duration of the experiment. Six of the seven ecotoxicological tests applied showed no difference between the control and treated soils. The treatment applied in this study may offer a means to remediate CLD-contaminated soils, especially nitisol and ferralsol.
Sébastien Bristeau - One of the best experts on this subject based on the ideXlab platform.
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laboratory study on the mobility of chlordecone and seven of its transformation products formed by Chemical Reduction in nitisol lysimeters of a banana plantation in martinique french caribbean
2020Co-Authors: Patrick Ollivier, Sébastien Bristeau, Jeremy Engevin, Christophe MouvetAbstract:Abstract The contamination by chlordecone (CLD) of soils and water in the French Caribbean (FC) has major environmental and human health impacts. In Situ Chemical Reduction (ISCR) is a promising method to degrade CLD but it generates transformation products (TPs). Here, the fate and transport of CLD and its TPs have been studied using three lysimeters, 65–70 cm-long and 20 cm in diameter, collected from a CLD contaminated nitisol in the FC. A simulated ISCR remediation process (Sim-ISCR) was applied to the top 15 cm layer. An equivalent of 9.8 years of effective rainfall was simulated during the 451 days of the experiments. CLD and seven TPs were analyzed in soils, soil pore waters and outflow waters of the lysimeters before and after the Sim-ISCR. CLD concentration in the soil pore waters increases with depth. In the Sim-ISCR treated layer, the CLD contamination was lowered by 41 to 47% in the soil and by 48 to 73% in the soil pore water. In the lysimeters outflow, however, the CLD concentration was lowered by only 13 to 25%, the flux of CLD from the untreated 50–55 cm of the profile concealing much of the beneficial impact of treating the top 15 cm. Remediating by ISCR the topsoil only will therefore not be sufficient for preventing further CLD contamination of the underlying groundwater. Sim-ISCR generated 5-hydroCLD in soils and waters and, to a much lesser extent, a trihydroCLD, a tetrahydroCLD, a pentahydroCLD and a heptahydroCLD. 5-hydroCLD is more mobile than CLD, but it still interacts strongly with the soil. The 5-hydroCLD values measured in the outflow were up to a factor of 4.4 lower than in the treated soil pore waters, indicating some natural attenuation.
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Physico-Chemical and agronomic results of soil remediation by In Situ Chemical Reduction applied to a chlordecone-contaminated nitisol at plot scale in a French Caribbean banana plantation
2020Co-Authors: Christophe Mouvet, Sébastien Bristeau, Bastien Collet, Jean-marie Gaude, Luc Rangon, Mathlide Senergues, Magalie Lesueur-jannoyer, Alexandra Jestin, Jennifer Hellal, Thierry WoignierAbstract:The In Situ Chemical Reduction (ISCR) process was tested in a nitisol in a French Caribbean banana plantation using five different soil amendments. The addition of 2.8% or 4.0% of Zero Valent Iron (ZVI; dw/dw, 2 different trial plots) in the 0–40-cm soil layer lowered the initial chlordecone (CLD) concentration by up to 74% or 69% in 37 days or 94 days, with 75% of the decrease achieved after only 21 or 24 days of treatment depending on the trial plot. The addition of commercially available Daramend® was also tested by applying the 6% dose (dw/dw) recommended by the manufacturer and using either the regular alfalfa-based product or a bagasse-based product specifically formulated for the study. Both significantly lowered CLD concentrations, but to a lesser extent than with the ZVI-only amendment. A bagasse-ZVI mixture prepared on site produced results slightly better than the two Daramend®. The percentage decreases in CLD concentrations were correlated with the negative redox potentials achieved. In all the trial plots, dechlorinated transformation products appeared in the soil and soil water as the CLD concentrations decreased, with H atoms replacing up to 4 and 7 of the 10 Cl atoms, respectively. None of these degradation products appeared to accumulate in the soil or soil water during the treatment. Instead, the reverse occurred, with an overall downward trend in their concentrations over time. The effects of ISCR treatment on agronomic and human health–related parameters were measured in three different crops. The radishes produced with some treatments were visually of lower quality or smaller in size than those grown in the control plots. Lower yields were observed for the cucumbers and sweet potatoes grown after applying the bagasse-based amendments. Mortality among cucumber seedlings was observed after treatment with ZVI only. Simple operational solutions should suffice to remedy these negative agronomic effects. As regards human health–related effects, the CLD concentrations in radishes grown with three of the amendments were significantly lower than in the two control plots and well below the maximum residue level (MRL), which was substantially exceeded in the radishes grown on untreated soil. For cucumbers, the treatments with regular Daramend® and with a local bagasse-ZVI mixture produced fruits with CLD below the MRL and also below the concentrations in one of the two control plots. As for the sweet potatoes, adding a bagasse-ZVI mixture had a significant positive effect by decreasing contamination below the levels in the two control plots and below the MRL.
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In vivo comparison of the proangiogenic properties of chlordecone and three of its dechlorinated derivatives formed by in situ Chemical Reduction
2019Co-Authors: Eid Alabed Alibrahim, Sébastien Bristeau, Samuel Legeay, Pierre-andré Billat, Emmanuelle Bichon, Ingrid Guiffard, Jean-philippe Antignac, Pierre Legras, Jérôme Roux, Nicolas ClereAbstract:In situ Chemical Reduction (ISCR) has been identified as a possible way for the remediation of soils contaminated by chlordecone (CLD). Evidences provided by the literature indicate an association between the development of prostate cancer and CLD exposure (Multigner et al. 2010 ). In a previous in vitro study, we demonstrated that the two main dechlorinated CLD derivatives formed by ISCR, CLD-1Cl, and CLD-3Cl have lower cytotoxicity and proangiogenic properties than CLD itself (Legeay et al. 2017 ). By contrast, nothing is known on the in vivo proangiogenic effect of these dechlorinated derivatives. Based on in vitro data, the aims of this study were therefore to evaluate the in vivo influence of CLD and three of its dechlorinated metabolites in the control of neovascularization in a mice model of prostate cancer. The proangiogenic effect of CLD and three of its dechlorinated derivatives, CLD-1Cl, CLD-3Cl, and CLD-4Cl, was evaluated on a murine model of human prostate tumor (PC-3) treated, at two exposure levels: 33 μg/kg and 1.7 μg/kg respectively reflecting acute and chronic toxic exposure in human. The results of serum measurements show that, for the same ingested dose, the three metabolite concentrations were significantly lower than that of CLD. Dechlorination of CLD lead therefore to molecules that are biologically absorbed or metabolized, or both, faster than the parent molecule. Prostate tumor growth was lower in the groups treated by the three metabolites compared to the one treated by CLD. The vascularization measured on the tumor sections was inversely proportional to the rate of dechlorination, the treatment with CLD-4Cl showing no difference with control animals treated with only the vehicle oil used for all substances tested. We can therefore conclude that the proangiogenic effect of CLD is significantly decreased following the ISCR-resulting dechlorination. Further investigations are needed to elucidate the molecular mechanisms by which dechlorination of CLD reduces proangiogenic effects in prostate tumor.
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Remediation by Chemical Reduction in laboratory mesocosms of three chlordecone-contaminated tropical soils
2017Co-Authors: Christophe Mouvet, Dominique Breeze, Marie Christine Dictor, Sébastien Bristeau, Anne MercierAbstract:Chlordecone (CLD), a highly persistent organochlorine pesticide commonly encountered in French West Indies (FWI) agricultural soils, represents a major source of contamination of FWI ecosystems. The potential of Chemical Reduction for remediation of CLD-contaminated soil has been investigated in laboratory pilot-scale 80 kg mesocosms for andosol, ferralsol, and nitisol from FWI banana plantations. Six cycles consisting of a 3-week reducing phase followed by a 1-week oxidizing phase were applied, with 2 % (dw/dw) Daramend® (organic plant matter fortified with zero valent iron) added at the start of each cycle. Complementary amendments of zero valent iron and zinc (total of 3 % dw/dw) were added at the start of the first three cycles. After the 6-month treatment, the CLD soil concentration was lowered by 74 % in nitisol, 71 % in ferralsol, and 22 % in andosol. Eleven CLD-dechlorinated transformation products, from mono- to penta-dechlorinated, were identified. None of them accumulated over the duration of the experiment. Six of the seven ecotoxicological tests applied showed no difference between the control and treated soils. The treatment applied in this study may offer a means to remediate CLD-contaminated soils, especially nitisol and ferralsol.
Parviz Parvin - One of the best experts on this subject based on the ideXlab platform.
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surface structural alteration of multi walled carbon nanotubes decorated by nickel nanoparticles based on laser ablation Chemical Reduction methods to enhance hydrogen storage properties
2019Co-Authors: Mohsen Mehrabi, Parviz Parvin, A Reyhani, S Z MortazaviAbstract:Abstract The catalytic effect of nickel is addressed to decorate the multi-walled carbon nanotubes for the purpose of hydrogen storage. The hydrogen sorption/desorption are investigated using the volumetric technique. Nickel nanoparticles are distributed on the surface of nanotubes using the laser ablation/Chemical Reduction treatments. The hydrogen uptake is elevated at higher nickel population up to a certain value and then experiences a significant drop for larger nickel content. The laser treatment is accompanied by the induced pores around nanotubes. This gives rise to the creation of the larger pores at higher laser doses leading to decrease the hydrogen trapping. Despite the pore size distribution strongly alters during both synthesis methods, however the abundance of small pore size in laser treatments is relatively higher than the that of the other technique. In comparison, the laser ablation demonstrates a relatively smaller desorption temperature against Chemical one, mainly owing to the formation of larger pore size/volume. Generally, the hydrogen trapping efficiently takes place in the laser treated samples against Chemical Reduction method. The highest value of hydrogen storage ∼1% (0.6% weight) is corresponding to 12.3% (13% weight) of nickel loading via the laser ablation (Chemical Reduction).
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hydrogen storage in multi walled carbon nanotubes decorated with palladium nanoparticles using laser ablation Chemical Reduction methods
2017Co-Authors: Mohsen Mehrabi, Parviz Parvin, A Reyhani, S Z MortazaviAbstract:Hydrogen storage properties of multi-walled carbon nanotubes (MWCNTs) decorated by palladium nanoparticles (Pd NPs) are investigated using laser ablation and Chemical Reduction methods, revealing great differences between the two techniques. In the case of laser ablation, the hydrogen uptake is elevated with the Pd content up to a certain value and then undergoes a notable drop, whereas the hydrogen content linearly scales up with the Pd loading during the Chemical Reduction method. When the Pd loading is low, the storage capacity of the laser treated samples is higher than those decorated via the other technique of interest. During laser ablation, the larger Pd content is accompanied by plentiful pore formation, leading to larger pore sizes at higher doses, which seriously reduces the hydrogen uptake. Moreover, the desorption temperature of hydrogen notably increases in terms of Pd loading. In comparison, the laser ablation method undergoes a relatively smaller desorption temperature, mainly due to the larger pore size/volume.