Speciation Chemistry

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Hallvard F Svendsen - One of the best experts on this subject based on the ideXlab platform.

  • kinetics of carbon dioxide absorption into aqueous amine amino acid salt 3 methylamino propylamine sarcosine solution
    Chemical Engineering Science, 2011
    Co-Authors: Ugochukwu E. Aronu, Ardi Hartono, Hallvard F Svendsen
    Abstract:

    Abstract A string of discs contactor apparatus was used to measure the CO 2 absorption kinetics into an unloaded aqueous amine amino acid salt, 3-(methylamino)propylamine/sarcosine, SARMAPA solution. The solution was prepared by mixing equinormal proportions of sarcosine, SAR and 3-(methylamino)propylamine, MAPA. Experiments were carried out for the concentration range 1.0–5.0 kmol m −3 and for temperatures 25–62 °C. The termolecular mechanism was applied to interpret the experimental data after correcting for non-idealities from the ionic strength using an ionic correction factor. A model correlation without the ionic strength correction was found not to give a good fit to the experimental data. The reaction rate constant for aqueous SARMAPA was determined and found to be comparable to values for amines. It increases significantly with temperature and concentration. The reaction rate constant for water is higher in the SARMAPA system than in amine systems indicating that water contributes significantly to the overall absorption rate and more than in amine systems. The reaction order with respect to the amino acid salt, SARMAPA, concentration varies from 1.06 to 1.43 with an average value of 1.21. A simplified approach applied to the complex Speciation Chemistry of the amine amino acid salt, AAAS, system gave a good representation of the experimentally observed kinetic rate constant.

  • Kinetics of carbon dioxide absorption into aqueous amine amino acid salt: 3-(methylamino)propylamine/sarcosine solution
    Chemical Engineering Science, 2011
    Co-Authors: Ugochukwu E. Aronu, Ardi Hartono, Hallvard F Svendsen
    Abstract:

    Abstract A string of discs contactor apparatus was used to measure the CO 2 absorption kinetics into an unloaded aqueous amine amino acid salt, 3-(methylamino)propylamine/sarcosine, SARMAPA solution. The solution was prepared by mixing equinormal proportions of sarcosine, SAR and 3-(methylamino)propylamine, MAPA. Experiments were carried out for the concentration range 1.0–5.0 kmol m −3 and for temperatures 25–62 °C. The termolecular mechanism was applied to interpret the experimental data after correcting for non-idealities from the ionic strength using an ionic correction factor. A model correlation without the ionic strength correction was found not to give a good fit to the experimental data. The reaction rate constant for aqueous SARMAPA was determined and found to be comparable to values for amines. It increases significantly with temperature and concentration. The reaction rate constant for water is higher in the SARMAPA system than in amine systems indicating that water contributes significantly to the overall absorption rate and more than in amine systems. The reaction order with respect to the amino acid salt, SARMAPA, concentration varies from 1.06 to 1.43 with an average value of 1.21. A simplified approach applied to the complex Speciation Chemistry of the amine amino acid salt, AAAS, system gave a good representation of the experimentally observed kinetic rate constant.

Paula M C Antunes - One of the best experts on this subject based on the ideXlab platform.

  • lead toxicity to lemna minor predicted using a metal Speciation Chemistry approach
    Environmental Toxicology and Chemistry, 2014
    Co-Authors: Paula M C Antunes, Nancy J Kreager
    Abstract:

    In the present study, predictive measures for Pb toxicity and Lemna minor were developed from bioassays with 7 surface waters having varied chemistries (0.5–12.5 mg/L dissolved organic carbon, pH of 5.4–8.3, and water hardness of 8–266 mg/L CaCO3). As expected based on water quality, 10%, 20%, and 50% inhibitory concentration (IC10, IC20, and IC50, respectively) values expressed as percent net root elongation (%NRE) varied widely (e.g., IC20s ranging from 306 nM to >6920 nM total dissolved Pb), with unbounded values limited by Pb solubility. In considering chemical Speciation, %NRE variability was better explained when both Pb hydroxides and the free lead ion were defined as bioavailable (i.e., f{OH}) and colloidal Fe(III)(OH)3 precipitates were permitted to form and sorb metals (using FeOx as the binding phase). Although cause and effect could not be established because of covariance with alkalinity (p = 0.08), water hardness correlated strongly (r2 = 0.998, p < 0.0001) with the concentration of total Pb in true solution ([Pb]T_True solution). Using these correlations as the basis for predictions (i.e., [Pb]T_True solution vs water hardness and %NRE vs f{OH}), IC20 and IC50 values produced were within a factor of 2.9 times and 2.2 times those measured, respectively. The results provide much needed effect data for L. minor and highlight the importance of chemical Speciation in Pb-based risk assessments for aquatic macrophytes. Environ Toxicol Chem 2014;33:2225–2233. © 2014 SETAC

  • Lead toxicity to Lemna minor predicted using a metal Speciation Chemistry approach
    Environmental Toxicology and Chemistry, 2014
    Co-Authors: Paula M C Antunes, Nancy J Kreager
    Abstract:

    In the present study, predictive measures for Pb toxicity and Lemna minor were developed from bioassays with 7 surface waters having varied chemistries (0.5–12.5 mg/L dissolved organic carbon, pH of 5.4–8.3, and water hardness of 8–266 mg/L CaCO3). As expected based on water quality, 10%, 20%, and 50% inhibitory concentration (IC10, IC20, and IC50, respectively) values expressed as percent net root elongation (%NRE) varied widely (e.g., IC20s ranging from 306 nM to >6920 nM total dissolved Pb), with unbounded values limited by Pb solubility. In considering chemical Speciation, %NRE variability was better explained when both Pb hydroxides and the free lead ion were defined as bioavailable (i.e., f{OH}) and colloidal Fe(III)(OH)3 precipitates were permitted to form and sorb metals (using FeOx as the binding phase). Although cause and effect could not be established because of covariance with alkalinity (p = 0.08), water hardness correlated strongly (r2 = 0.998, p 

Ugochukwu E. Aronu - One of the best experts on this subject based on the ideXlab platform.

  • kinetics of carbon dioxide absorption into aqueous amine amino acid salt 3 methylamino propylamine sarcosine solution
    Chemical Engineering Science, 2011
    Co-Authors: Ugochukwu E. Aronu, Ardi Hartono, Hallvard F Svendsen
    Abstract:

    Abstract A string of discs contactor apparatus was used to measure the CO 2 absorption kinetics into an unloaded aqueous amine amino acid salt, 3-(methylamino)propylamine/sarcosine, SARMAPA solution. The solution was prepared by mixing equinormal proportions of sarcosine, SAR and 3-(methylamino)propylamine, MAPA. Experiments were carried out for the concentration range 1.0–5.0 kmol m −3 and for temperatures 25–62 °C. The termolecular mechanism was applied to interpret the experimental data after correcting for non-idealities from the ionic strength using an ionic correction factor. A model correlation without the ionic strength correction was found not to give a good fit to the experimental data. The reaction rate constant for aqueous SARMAPA was determined and found to be comparable to values for amines. It increases significantly with temperature and concentration. The reaction rate constant for water is higher in the SARMAPA system than in amine systems indicating that water contributes significantly to the overall absorption rate and more than in amine systems. The reaction order with respect to the amino acid salt, SARMAPA, concentration varies from 1.06 to 1.43 with an average value of 1.21. A simplified approach applied to the complex Speciation Chemistry of the amine amino acid salt, AAAS, system gave a good representation of the experimentally observed kinetic rate constant.

  • Kinetics of carbon dioxide absorption into aqueous amine amino acid salt: 3-(methylamino)propylamine/sarcosine solution
    Chemical Engineering Science, 2011
    Co-Authors: Ugochukwu E. Aronu, Ardi Hartono, Hallvard F Svendsen
    Abstract:

    Abstract A string of discs contactor apparatus was used to measure the CO 2 absorption kinetics into an unloaded aqueous amine amino acid salt, 3-(methylamino)propylamine/sarcosine, SARMAPA solution. The solution was prepared by mixing equinormal proportions of sarcosine, SAR and 3-(methylamino)propylamine, MAPA. Experiments were carried out for the concentration range 1.0–5.0 kmol m −3 and for temperatures 25–62 °C. The termolecular mechanism was applied to interpret the experimental data after correcting for non-idealities from the ionic strength using an ionic correction factor. A model correlation without the ionic strength correction was found not to give a good fit to the experimental data. The reaction rate constant for aqueous SARMAPA was determined and found to be comparable to values for amines. It increases significantly with temperature and concentration. The reaction rate constant for water is higher in the SARMAPA system than in amine systems indicating that water contributes significantly to the overall absorption rate and more than in amine systems. The reaction order with respect to the amino acid salt, SARMAPA, concentration varies from 1.06 to 1.43 with an average value of 1.21. A simplified approach applied to the complex Speciation Chemistry of the amine amino acid salt, AAAS, system gave a good representation of the experimentally observed kinetic rate constant.

Nancy J Kreager - One of the best experts on this subject based on the ideXlab platform.

  • lead toxicity to lemna minor predicted using a metal Speciation Chemistry approach
    Environmental Toxicology and Chemistry, 2014
    Co-Authors: Paula M C Antunes, Nancy J Kreager
    Abstract:

    In the present study, predictive measures for Pb toxicity and Lemna minor were developed from bioassays with 7 surface waters having varied chemistries (0.5–12.5 mg/L dissolved organic carbon, pH of 5.4–8.3, and water hardness of 8–266 mg/L CaCO3). As expected based on water quality, 10%, 20%, and 50% inhibitory concentration (IC10, IC20, and IC50, respectively) values expressed as percent net root elongation (%NRE) varied widely (e.g., IC20s ranging from 306 nM to >6920 nM total dissolved Pb), with unbounded values limited by Pb solubility. In considering chemical Speciation, %NRE variability was better explained when both Pb hydroxides and the free lead ion were defined as bioavailable (i.e., f{OH}) and colloidal Fe(III)(OH)3 precipitates were permitted to form and sorb metals (using FeOx as the binding phase). Although cause and effect could not be established because of covariance with alkalinity (p = 0.08), water hardness correlated strongly (r2 = 0.998, p < 0.0001) with the concentration of total Pb in true solution ([Pb]T_True solution). Using these correlations as the basis for predictions (i.e., [Pb]T_True solution vs water hardness and %NRE vs f{OH}), IC20 and IC50 values produced were within a factor of 2.9 times and 2.2 times those measured, respectively. The results provide much needed effect data for L. minor and highlight the importance of chemical Speciation in Pb-based risk assessments for aquatic macrophytes. Environ Toxicol Chem 2014;33:2225–2233. © 2014 SETAC

  • Lead toxicity to Lemna minor predicted using a metal Speciation Chemistry approach
    Environmental Toxicology and Chemistry, 2014
    Co-Authors: Paula M C Antunes, Nancy J Kreager
    Abstract:

    In the present study, predictive measures for Pb toxicity and Lemna minor were developed from bioassays with 7 surface waters having varied chemistries (0.5–12.5 mg/L dissolved organic carbon, pH of 5.4–8.3, and water hardness of 8–266 mg/L CaCO3). As expected based on water quality, 10%, 20%, and 50% inhibitory concentration (IC10, IC20, and IC50, respectively) values expressed as percent net root elongation (%NRE) varied widely (e.g., IC20s ranging from 306 nM to >6920 nM total dissolved Pb), with unbounded values limited by Pb solubility. In considering chemical Speciation, %NRE variability was better explained when both Pb hydroxides and the free lead ion were defined as bioavailable (i.e., f{OH}) and colloidal Fe(III)(OH)3 precipitates were permitted to form and sorb metals (using FeOx as the binding phase). Although cause and effect could not be established because of covariance with alkalinity (p = 0.08), water hardness correlated strongly (r2 = 0.998, p 

Ardi Hartono - One of the best experts on this subject based on the ideXlab platform.

  • kinetics of carbon dioxide absorption into aqueous amine amino acid salt 3 methylamino propylamine sarcosine solution
    Chemical Engineering Science, 2011
    Co-Authors: Ugochukwu E. Aronu, Ardi Hartono, Hallvard F Svendsen
    Abstract:

    Abstract A string of discs contactor apparatus was used to measure the CO 2 absorption kinetics into an unloaded aqueous amine amino acid salt, 3-(methylamino)propylamine/sarcosine, SARMAPA solution. The solution was prepared by mixing equinormal proportions of sarcosine, SAR and 3-(methylamino)propylamine, MAPA. Experiments were carried out for the concentration range 1.0–5.0 kmol m −3 and for temperatures 25–62 °C. The termolecular mechanism was applied to interpret the experimental data after correcting for non-idealities from the ionic strength using an ionic correction factor. A model correlation without the ionic strength correction was found not to give a good fit to the experimental data. The reaction rate constant for aqueous SARMAPA was determined and found to be comparable to values for amines. It increases significantly with temperature and concentration. The reaction rate constant for water is higher in the SARMAPA system than in amine systems indicating that water contributes significantly to the overall absorption rate and more than in amine systems. The reaction order with respect to the amino acid salt, SARMAPA, concentration varies from 1.06 to 1.43 with an average value of 1.21. A simplified approach applied to the complex Speciation Chemistry of the amine amino acid salt, AAAS, system gave a good representation of the experimentally observed kinetic rate constant.

  • Kinetics of carbon dioxide absorption into aqueous amine amino acid salt: 3-(methylamino)propylamine/sarcosine solution
    Chemical Engineering Science, 2011
    Co-Authors: Ugochukwu E. Aronu, Ardi Hartono, Hallvard F Svendsen
    Abstract:

    Abstract A string of discs contactor apparatus was used to measure the CO 2 absorption kinetics into an unloaded aqueous amine amino acid salt, 3-(methylamino)propylamine/sarcosine, SARMAPA solution. The solution was prepared by mixing equinormal proportions of sarcosine, SAR and 3-(methylamino)propylamine, MAPA. Experiments were carried out for the concentration range 1.0–5.0 kmol m −3 and for temperatures 25–62 °C. The termolecular mechanism was applied to interpret the experimental data after correcting for non-idealities from the ionic strength using an ionic correction factor. A model correlation without the ionic strength correction was found not to give a good fit to the experimental data. The reaction rate constant for aqueous SARMAPA was determined and found to be comparable to values for amines. It increases significantly with temperature and concentration. The reaction rate constant for water is higher in the SARMAPA system than in amine systems indicating that water contributes significantly to the overall absorption rate and more than in amine systems. The reaction order with respect to the amino acid salt, SARMAPA, concentration varies from 1.06 to 1.43 with an average value of 1.21. A simplified approach applied to the complex Speciation Chemistry of the amine amino acid salt, AAAS, system gave a good representation of the experimentally observed kinetic rate constant.