Decoding gas-solid interaction effects on adsorption isotherm shape: I. Non-polar adsorptives

S. Hadi Madani, Phillip Kwong, Francisco Rodríguez-Reinoso, Mark J. Biggs, Phillip Pendleton*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)
94 Downloads (Pure)


A suite of non-polar adsorptives of different kinetic diameters and shape were used to determine adsorption and pore filling mechanism of a well-characterised poly(furfuryl alcohol)-based activated carbon. Triplicate measured Type I adsorption isotherms for each adsorptive were averaged to provide standard deviation in relative pressures and associated amounts adsorbed. Plateau amounts adsorbed for N2, Ar, CH4, and C6H6, provided Gurvitsch volumes averaged to 0.368 ± 0.015 cm3(liq)/g. The calculated Gurvitsch volumes were compared with those derived via the Dubinin-Radushkevich (DR) equation. Additional adsorptives were CO2, iso-butane and SF6. The results of these 7 adsorptives were used to qualitatively analyse and decode a micropore filling adsorption mechanism. The DR equation was also used for further analysis of the pore filling mechanism. Based on the adsorbate-adsorbate and adsorbate-adsorbent interactions, adsorbates were classified into three groups: (a) Non-polar with non-specific interactions (no dipole, no quadrupole, not readily polarizable: Ar, N2, CH4 and iso-butane), adsorbing as a continuous uptake over the observed relative pressure range; (b) Non-polar adsorptives with potential for specific interactions (no dipole, quadrupole moment: CO2 and C6H6), adsorbing as a condensation process over a relatively narrow relative pressure range in a medium pressure range; (c) Halogenated adsorptives (no dipole, no quadrupole, polarizable: SF6), adsorbing with an S-shaped uptake extending over a relatively broad relative pressure range.

Original languageEnglish
Pages (from-to)76-83
Number of pages8
JournalMicroporous and Mesoporous Materials
Early online date16 Jan 2018
Publication statusPublished - 1 Jul 2018


  • Adsorption
  • Mechanism
  • Non-specific interaction
  • Polarity
  • Polarizability

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials


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