Accumulated Gibbs free energy as a quantitative measure of desorption hysteresis associated with the formation of metastable states.

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  • Author(s): Borisover M;Borisover M
  • Source:
    Chemosphere [Chemosphere] 2019 Jan; Vol. 215, pp. 490-499. Date of Electronic Publication: 2018 Oct 09.
  • Publication Type:
    Journal Article
  • Language:
    English
  • Additional Information
    • Source:
      Publisher: Elsevier Science Ltd Country of Publication: England NLM ID: 0320657 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1879-1298 (Electronic) Linking ISSN: 00456535 NLM ISO Abbreviation: Chemosphere Subsets: MEDLINE
    • Publication Information:
      Publication: Oxford : Elsevier Science Ltd
      Original Publication: Oxford, New York, : Pergamon Press.
    • Subject Terms:
      Adsorption* ; Thermodynamics*; Organic Chemicals/*chemistry; Kinetics ; Molecular Structure ; Soil/chemistry ; Soil Pollutants/analysis ; Soil Pollutants/chemistry
    • Abstract:
      The persistence of metastable states was proposed in the literature as one explanation for sorption-desorption hysteresis (SDH) of organic compounds on soils and sediments. When such metastable states freely exchange sorbate molecules with the surroundings and there is no spontaneous exit of a whole system from that state, it is possible to determine the extra Gibbs free energy (ΔG ext ) accumulated in a system due to the persistence of metastable states. A novel contribution of this paper is the characterization of SDH, in which the sorption isotherm (SI) and desorption isotherm (DI) do not close a loop, in terms of free energy needed to create "frozen", metastable states. To that end, liquid phase sorption of non-ionized sorbates is considered and by integrating over the sorption-desorption sequence, ΔG ext and an integral hysteresis index (IHI) were obtained. Experimental data collected from the literature on aqueous sorption and desorption of polyaromatic hydrocarbons, triazines and ureas were examined on soils, sediments, organic matter-rich sorbents, montmorillonites and fullerene. Positive ΔG ext values were obtained to quantify the thermodynamic potential for spontaneous exit from a metastable state that is not implemented due to the kinetic barriers. Relating the ΔG ext values to sorbate molecular structure and sorbent properties may allow the prediction of SDH for various chemicals on sorbents in which the sorbate-induced perturbation of a sorbent matrix is believed to be a cause for the formation of persistent metastable states and the appearance of a non-closed sorption-desorption sequence.
      (Copyright © 2018 Elsevier Ltd. All rights reserved.)
    • Contributed Indexing:
      Keywords: "Frozen" state; Clay; Free energy; Hysteresis; Natural organic matter; Sorption
    • Accession Number:
      0 (Organic Chemicals)
      0 (Soil)
      0 (Soil Pollutants)
    • Publication Date:
      Date Created: 20181020 Date Completed: 20181211 Latest Revision: 20181211
    • Publication Date:
      20231215
    • Accession Number:
      10.1016/j.chemosphere.2018.10.051
    • Accession Number:
      30340157