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L. M. Doubova - One of the best experts on this subject based on the ideXlab platform.

  • Building up an electrocatalytic activity scale of cathode materials for Organic Halide reductions
    Electrochimica Acta, 2005
    Co-Authors: C. Bellomunno, D. Bonanomi, Luigi Falciola, Mariangela Longhi, Patrizia R. Mussini, L. M. Doubova, G. Di Silvestro
    Abstract:

    A wide investigation on the electrochemical activity of four model Organic bromides has been carried out in acetonitrile on nine cathodes of widely different affinity for Halide anions (Pt, Zn, Hg, Sn, Bi, Pb, Au, Cu, Ag), and the electrocatalytic activities of the latter have been evaluated with respect to three possible inert reference cathode materials, i.e. glassy carbon, boron-doped diamond, and fluorinated boron-doped diamond. A general electrocatalytic activity scale for the process is proposed, with a discussion on its modulation by the configuration of the reacting molecule, and its connection with thermodynamic parameters accounting for Halide adsorption.

  • the role of surface morphology on the electrocatalytic reduction of Organic Halides on mono and polycrystalline silver
    Electrochimica Acta, 2003
    Co-Authors: S Ardizzone, L. M. Doubova, G Cappelletti, P R Mussini, Silvia Maria Passeri, S Rondinini
    Abstract:

    Abstract The electrocatalytic reduction of Organic Halides on silver, assumed to hinge on an attenuated radical intermediate R⋯X⋯Ag, is a reaction of great applicative interest that also provides an example of Organic electrocatalytic process particularly convenient for a mechanistic study. The complexity of the problem requires to analyze separately the roles of the many actors involved. The present work focuses on the role of the silver surface morphology, contrasting the reactivity of a series of model Halides in systematic CV experiments on (1 1 1), (1 1 0), and (1 0 0) silver monocrystals and on controlled polycrystalline silver surfaces of increasing roughness, in acetonitrile+tetraethylammonium perchlorate medium. The reduction potentials of the alkyl, glycosyl, and benzyl derivatives appear significantly shifted in the positive direction with increasing surface roughness (for polycrystals) or atomic densities and/or surface faceting (for monocrystals) by an extent linked with the molecular structure of the Organic Halide to be reduced. The addition of strongly specifically adsorbed iodide anions, resulting in surface screening, also results in a leveling effect of the catalytic properties of the different surfaces tested.

  • adsorption competition effects in the electrocatalytic reduction of Organic Halides on silver
    Journal of Electroanalytical Chemistry, 2002
    Co-Authors: S Ardizzone, G Cappelletti, P R Mussini, S Rondinini, L. M. Doubova
    Abstract:

    Abstract A systematic study of {silver ∣ inOrganic and/or Organic Halide} interphases is described, based on cyclovoltammetric and impedance experiments carried out on polycrystalline electrodes of high reproducibility (controlled by comparison with monocrystalline ones), in water and in acetonitrile. The adsorption competition is brought into focus (i) between the three inOrganic Halides Cl − , Br − , and I − , with the possible interference of ions from the supporting electrolyte, and (ii) between Organic and inOrganic Halides, especially iodides. Actually adsorption competition proves to be a determining factor in the electrocatalytic mechanism (a remarkable threshold effect being observed for the reduction potentials of Organic bromides in correspondence with the limiting negative potential for iodide anion adsorption). Vice versa, the variation of the reduction potentials of a given reacting molecule with the background electrolyte provides significant clues on the nature of the specifically adsorbed species.

Pratima Bajpai - One of the best experts on this subject based on the ideXlab platform.

  • decolorization and detoxification of extraction stage effluent from chlorine bleaching of kraft pulp by rhizopus oryzae
    Applied and Environmental Microbiology, 1999
    Co-Authors: R Nagarathnamma, Pratima Bajpai
    Abstract:

    Rhizopus oryzae, a zygomycete, was found to decolorize, dechlorinate, and detoxify bleach plant effluent at lower cosubstrate concentrations than the basidiomycetes previously investigated. With glucose at 1 g/liter, this fungus removed 92 to 95% of the color, 50% of the chemical oxygen demand, 72% of the adsorbable Organic Halide, and 37% of the extractable Organic Halide in 24 h at temperatures of 25 to 45°C and a pH of 3 to 5. Even without added cosubstrate the fungus removed up to 78% of the color. Monomeric chlorinated aromatic compounds were removed almost completely, and toxicity to zebra fish was eliminated. The fungal mycelium could be immobilized in polyurethane foam and used repeatedly to treat batches of effluent. The residue after treatment was not further improved by exposure to fresh R. oryzae mycelium.

  • decolorization and detoxification of extraction stage effluent from chlorine bleaching of kraft pulp by rhizopus oryzae
    Applied and Environmental Microbiology, 1999
    Co-Authors: R Nagarathnamma, Pratima Bajpai
    Abstract:

    Rhizopus oryzae, a zygomycete, was found to decolorize, dechlorinate, and detoxify bleach plant effluent at lower cosubstrate concentrations than the basidiomycetes previously investigated. With glucose at 1 g/liter, this fungus removed 92 to 95% of the color, 50% of the chemical oxygen demand, 72% of the adsorbable Organic Halide, and 37% of the extractable Organic Halide in 24 h at temperatures of 25 to 45°C and a pH of 3 to 5. Even without added cosubstrate the fungus removed up to 78% of the color. Monomeric chlorinated aromatic compounds were removed almost completely, and toxicity to zebra fish was eliminated. The fungal mycelium could be immobilized in polyurethane foam and used repeatedly to treat batches of effluent. The residue after treatment was not further improved by exposure to fresh R. oryzae mycelium.

S Rondinini - One of the best experts on this subject based on the ideXlab platform.

  • the role of surface morphology on the electrocatalytic reduction of Organic Halides on mono and polycrystalline silver
    Electrochimica Acta, 2003
    Co-Authors: S Ardizzone, L. M. Doubova, G Cappelletti, P R Mussini, Silvia Maria Passeri, S Rondinini
    Abstract:

    Abstract The electrocatalytic reduction of Organic Halides on silver, assumed to hinge on an attenuated radical intermediate R⋯X⋯Ag, is a reaction of great applicative interest that also provides an example of Organic electrocatalytic process particularly convenient for a mechanistic study. The complexity of the problem requires to analyze separately the roles of the many actors involved. The present work focuses on the role of the silver surface morphology, contrasting the reactivity of a series of model Halides in systematic CV experiments on (1 1 1), (1 1 0), and (1 0 0) silver monocrystals and on controlled polycrystalline silver surfaces of increasing roughness, in acetonitrile+tetraethylammonium perchlorate medium. The reduction potentials of the alkyl, glycosyl, and benzyl derivatives appear significantly shifted in the positive direction with increasing surface roughness (for polycrystals) or atomic densities and/or surface faceting (for monocrystals) by an extent linked with the molecular structure of the Organic Halide to be reduced. The addition of strongly specifically adsorbed iodide anions, resulting in surface screening, also results in a leveling effect of the catalytic properties of the different surfaces tested.

  • adsorption competition effects in the electrocatalytic reduction of Organic Halides on silver
    Journal of Electroanalytical Chemistry, 2002
    Co-Authors: S Ardizzone, G Cappelletti, P R Mussini, S Rondinini, L. M. Doubova
    Abstract:

    Abstract A systematic study of {silver ∣ inOrganic and/or Organic Halide} interphases is described, based on cyclovoltammetric and impedance experiments carried out on polycrystalline electrodes of high reproducibility (controlled by comparison with monocrystalline ones), in water and in acetonitrile. The adsorption competition is brought into focus (i) between the three inOrganic Halides Cl − , Br − , and I − , with the possible interference of ions from the supporting electrolyte, and (ii) between Organic and inOrganic Halides, especially iodides. Actually adsorption competition proves to be a determining factor in the electrocatalytic mechanism (a remarkable threshold effect being observed for the reduction potentials of Organic bromides in correspondence with the limiting negative potential for iodide anion adsorption). Vice versa, the variation of the reduction potentials of a given reacting molecule with the background electrolyte provides significant clues on the nature of the specifically adsorbed species.

S Ardizzone - One of the best experts on this subject based on the ideXlab platform.

  • the role of surface morphology on the electrocatalytic reduction of Organic Halides on mono and polycrystalline silver
    Electrochimica Acta, 2003
    Co-Authors: S Ardizzone, L. M. Doubova, G Cappelletti, P R Mussini, Silvia Maria Passeri, S Rondinini
    Abstract:

    Abstract The electrocatalytic reduction of Organic Halides on silver, assumed to hinge on an attenuated radical intermediate R⋯X⋯Ag, is a reaction of great applicative interest that also provides an example of Organic electrocatalytic process particularly convenient for a mechanistic study. The complexity of the problem requires to analyze separately the roles of the many actors involved. The present work focuses on the role of the silver surface morphology, contrasting the reactivity of a series of model Halides in systematic CV experiments on (1 1 1), (1 1 0), and (1 0 0) silver monocrystals and on controlled polycrystalline silver surfaces of increasing roughness, in acetonitrile+tetraethylammonium perchlorate medium. The reduction potentials of the alkyl, glycosyl, and benzyl derivatives appear significantly shifted in the positive direction with increasing surface roughness (for polycrystals) or atomic densities and/or surface faceting (for monocrystals) by an extent linked with the molecular structure of the Organic Halide to be reduced. The addition of strongly specifically adsorbed iodide anions, resulting in surface screening, also results in a leveling effect of the catalytic properties of the different surfaces tested.

  • adsorption competition effects in the electrocatalytic reduction of Organic Halides on silver
    Journal of Electroanalytical Chemistry, 2002
    Co-Authors: S Ardizzone, G Cappelletti, P R Mussini, S Rondinini, L. M. Doubova
    Abstract:

    Abstract A systematic study of {silver ∣ inOrganic and/or Organic Halide} interphases is described, based on cyclovoltammetric and impedance experiments carried out on polycrystalline electrodes of high reproducibility (controlled by comparison with monocrystalline ones), in water and in acetonitrile. The adsorption competition is brought into focus (i) between the three inOrganic Halides Cl − , Br − , and I − , with the possible interference of ions from the supporting electrolyte, and (ii) between Organic and inOrganic Halides, especially iodides. Actually adsorption competition proves to be a determining factor in the electrocatalytic mechanism (a remarkable threshold effect being observed for the reduction potentials of Organic bromides in correspondence with the limiting negative potential for iodide anion adsorption). Vice versa, the variation of the reduction potentials of a given reacting molecule with the background electrolyte provides significant clues on the nature of the specifically adsorbed species.

R Nagarathnamma - One of the best experts on this subject based on the ideXlab platform.

  • decolorization and detoxification of extraction stage effluent from chlorine bleaching of kraft pulp by rhizopus oryzae
    Applied and Environmental Microbiology, 1999
    Co-Authors: R Nagarathnamma, Pratima Bajpai
    Abstract:

    Rhizopus oryzae, a zygomycete, was found to decolorize, dechlorinate, and detoxify bleach plant effluent at lower cosubstrate concentrations than the basidiomycetes previously investigated. With glucose at 1 g/liter, this fungus removed 92 to 95% of the color, 50% of the chemical oxygen demand, 72% of the adsorbable Organic Halide, and 37% of the extractable Organic Halide in 24 h at temperatures of 25 to 45°C and a pH of 3 to 5. Even without added cosubstrate the fungus removed up to 78% of the color. Monomeric chlorinated aromatic compounds were removed almost completely, and toxicity to zebra fish was eliminated. The fungal mycelium could be immobilized in polyurethane foam and used repeatedly to treat batches of effluent. The residue after treatment was not further improved by exposure to fresh R. oryzae mycelium.

  • decolorization and detoxification of extraction stage effluent from chlorine bleaching of kraft pulp by rhizopus oryzae
    Applied and Environmental Microbiology, 1999
    Co-Authors: R Nagarathnamma, Pratima Bajpai
    Abstract:

    Rhizopus oryzae, a zygomycete, was found to decolorize, dechlorinate, and detoxify bleach plant effluent at lower cosubstrate concentrations than the basidiomycetes previously investigated. With glucose at 1 g/liter, this fungus removed 92 to 95% of the color, 50% of the chemical oxygen demand, 72% of the adsorbable Organic Halide, and 37% of the extractable Organic Halide in 24 h at temperatures of 25 to 45°C and a pH of 3 to 5. Even without added cosubstrate the fungus removed up to 78% of the color. Monomeric chlorinated aromatic compounds were removed almost completely, and toxicity to zebra fish was eliminated. The fungal mycelium could be immobilized in polyurethane foam and used repeatedly to treat batches of effluent. The residue after treatment was not further improved by exposure to fresh R. oryzae mycelium.