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Title: Kinetic study of supercritical fluid extraction of organic contaminants from heterogeneous environmental samples with carbon dioxide and elevated temperatures

Abstract

Supercritical fluid extraction (SFE) rates of spiked polychlorinated dibenzo-p-dioxins (PCDDs) from Florisil, spiked [{sup 13}C]PCDDs and native PCDDs from fly ash, and spiked [{sup 2}H]polycyclic aromatic hydrocarbons (PAHs) and native PAHs from marine sediment and railroad bed soil were examined at 40, 120, and 200 {degree}C, while constant fluid density (d = 0.67 g/mL) and flow rate were maintained. In all cases, native analytes were extracted more slowly than spiked analytes, suggesting that additional processes affect SFE rates of native analytes. A kinetic model was used that could help distinguish between these processes and included terms for matrix-fluid mass transport, as well as partitioning and bulk mass transport in the supercritical fluid. Using a three-rate constant desorption model to describe mass transport, good correlations (r{sup 2} > 0.9 in most cases) were obtained with experimental data for native analytes, and desorption rate constants suggest that analyte-matrix interactions are strong. The results of this study show that increasing the extraction temperature is a simple and effective method to increase SFE rates while still exploiting the advantages of supercritical CO{sub 2}, and can be used regardless of whether slow SFE rates are due to poor partitioning into the fluid or limited bymore » slow desorption due to strong analyte-matrix interactions. 29 refs., 7 figs., 3 tabs.« less

Authors:
 [1]; ;  [1];  [2]
  1. Univ. of North Dakota, Grand Forks, ND (United States)
  2. Univ. of Waterloo (Canada)
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
53971
Resource Type:
Journal Article
Journal Name:
Analytical Chemistry (Washington)
Additional Journal Information:
Journal Volume: 67; Journal Issue: 10; Other Information: PBD: 15 May 1995
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 99 MATHEMATICS, COMPUTERS, INFORMATION SCIENCE, MANAGEMENT, LAW, MISCELLANEOUS; 54 ENVIRONMENTAL SCIENCES; DIOXIN; SUPERCRITICAL GAS EXTRACTION; POLYCYCLIC AROMATIC HYDROCARBONS; CARBON DIOXIDE; TEMPERATURE RANGE 0273-0400 K; TEMPERATURE DEPENDENCE; MATHEMATICAL MODELS; DESORPTION; FLY ASH; MASS TRANSFER; KINETICS; POLLUTION CONTROL

Citation Formats

Langenfeld, J J, Univ. of Waterloo, Hawthorne, S B, Miller, D J, and Pawliszyn, J. Kinetic study of supercritical fluid extraction of organic contaminants from heterogeneous environmental samples with carbon dioxide and elevated temperatures. United States: N. p., 1995. Web. doi:10.1021/ac00106a013.
Langenfeld, J J, Univ. of Waterloo, Hawthorne, S B, Miller, D J, & Pawliszyn, J. Kinetic study of supercritical fluid extraction of organic contaminants from heterogeneous environmental samples with carbon dioxide and elevated temperatures. United States. https://doi.org/10.1021/ac00106a013
Langenfeld, J J, Univ. of Waterloo, Hawthorne, S B, Miller, D J, and Pawliszyn, J. Mon . "Kinetic study of supercritical fluid extraction of organic contaminants from heterogeneous environmental samples with carbon dioxide and elevated temperatures". United States. https://doi.org/10.1021/ac00106a013.
@article{osti_53971,
title = {Kinetic study of supercritical fluid extraction of organic contaminants from heterogeneous environmental samples with carbon dioxide and elevated temperatures},
author = {Langenfeld, J J and Univ. of Waterloo and Hawthorne, S B and Miller, D J and Pawliszyn, J},
abstractNote = {Supercritical fluid extraction (SFE) rates of spiked polychlorinated dibenzo-p-dioxins (PCDDs) from Florisil, spiked [{sup 13}C]PCDDs and native PCDDs from fly ash, and spiked [{sup 2}H]polycyclic aromatic hydrocarbons (PAHs) and native PAHs from marine sediment and railroad bed soil were examined at 40, 120, and 200 {degree}C, while constant fluid density (d = 0.67 g/mL) and flow rate were maintained. In all cases, native analytes were extracted more slowly than spiked analytes, suggesting that additional processes affect SFE rates of native analytes. A kinetic model was used that could help distinguish between these processes and included terms for matrix-fluid mass transport, as well as partitioning and bulk mass transport in the supercritical fluid. Using a three-rate constant desorption model to describe mass transport, good correlations (r{sup 2} > 0.9 in most cases) were obtained with experimental data for native analytes, and desorption rate constants suggest that analyte-matrix interactions are strong. The results of this study show that increasing the extraction temperature is a simple and effective method to increase SFE rates while still exploiting the advantages of supercritical CO{sub 2}, and can be used regardless of whether slow SFE rates are due to poor partitioning into the fluid or limited by slow desorption due to strong analyte-matrix interactions. 29 refs., 7 figs., 3 tabs.},
doi = {10.1021/ac00106a013},
url = {https://www.osti.gov/biblio/53971}, journal = {Analytical Chemistry (Washington)},
number = 10,
volume = 67,
place = {United States},
year = {1995},
month = {5}
}