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Distinctive sorption mechanisms of soil organic matter and mineral components as elucidated by organic vapor uptake kinetics
Author(s) -
Shih YangHsin,
Wu ShianChee
Publication year - 2005
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/05-186r.1
Subject(s) - sorption , environmental chemistry , chemistry , kaolinite , soil water , adsorption , organic matter , kinetics , humic acid , environmental remediation , soil organic matter , partition coefficient , toluene , soil science , mineralogy , contamination , organic chemistry , geology , ecology , fertilizer , physics , quantum mechanics , biology
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.