Isosteric heats of adsorption were determined for 18 compounds with low injection volumes. The isosteric heats of adsorption of benzene and hexane on the pretreated Diesel samples were compared with those of the same compounds on a graphitized carbon black. The peak shapes of the Diesel-sample chromatograms and the relationship between the injection volume and the retention volume are evidence of a heterogeneous surface and a type II adsorption isotherm. For two compounds, benzene and hexane, the effect of varying the surface coverage, by changing the injection volume, on the adsorption heats was determined. The differences between the heats of adsorption measured for the two Diesel samples is attributed to the difference in the quantities and identities of the extractable compounds (or presorbed materials) on the particulate samples. The adsorption energies reported are significant with respect to the bioavailability of the sorbed species.
ASJC Scopus subject areas
- Environmental Chemistry