Characteristic adsorption functions and the surface structure of solid adsorbents

Krisztina László, József Tóth

Research output: Contribution to journalArticle

4 Citations (Scopus)


A thermodynamic model of gas/solid adsorption has been constructed from two elements. The first is the original Gibbs equation. The second consists of functions ψ(Θ) or ψ(P) that are calculable from measured isotherms. Based on this model the characteristic adsorption functions (CAFs) were defined and calculated. The CAFs, which concentrate into one function all measured isotherms having the same change in relative free energy of the surface, are very sensitive to the structure of the adsorbents. This statement was tested with nitrogen isotherms measured at 77 K on well-characterized chemically/physically treated activated carbons prepared from poly(ethylene terephthalate). Changes in the surface structure were followed by small angle X-ray scattering (SAXS). This experimental approach made it possible to observe the correspondence between structural changes and the CAF.

Original languageEnglish
Pages (from-to)425-432
Number of pages8
JournalJournal of colloid and interface science
Issue number2
Publication statusPublished - Jun 15 2005



  • Characteristic adsorption functions (CAFs)
  • Correlations between CAF and SAXS measurements
  • Nitrogen isotherms measured on virgin and treated activated carbons
  • Sensitivity of CAFs to structure of adsorbents
  • Surface structure measured by SAXS

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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