Distinctive sorption mechanisms of soil organic matter and mineral components as elucidated by organic vapor uptake kinetics
Journal
Environmental Toxicology and Chemistry
Journal Volume
24
Journal Volume
24
Journal Issue
11
Journal Issue
11
Pages
2827-2832
Start Page
2827
End Page
2832
ISSN
07307268
Date Issued
2005-11
Author(s)
Wu, Shian-Chee
Abstract
Sorption kinetics and capacities of volatile organic compounds (VOCs) affect the remediation and fate of these pollutants in soils. The soil organic-mineral compositional heterogeneity complicates the transport and fate of VOCs in soils. The sorption kinetics of toluene vapor with two common soil components, kaolinite and humic acid, shows two distinct sorption patterns. Results with kaolinite are characteristic of surface adsorption, whereas results with humic acid are characteristic of solvation and partition effects. On soils, the kinetics of toluene vapor sorption show a two-stage sorption phenomenon. The first stage is reflective of surface adsorption (1-4 h to completion) and the second stage of much slower partitioning into soil organic matter, which was preceded by a lag phase (∼4 h) and took as long as 15 h for completion. The relative contributions of these two stages to soil uptake are quantifiable by two independent parameters, the soil organic fraction and the surface area. A better understanding of the effect of soil compositional heterogeneity on sorption kinetics and capacities facilitates our understanding of the prediction for the fate of organic contaminants in the environment.
Subjects
Adsorption
Humic acid
Kaolinite
Partition
Volatile organic compounds
SDGs
Type
journal article
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