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A quantitative analysis of the dynamics of the sorption of hydrophobic organic chemicals to suspended sediments
Author(s) -
Lick Wilbert,
Rapaka Venkatrao
Publication year - 1996
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 - 10.1002/etc.5620150704
Subject(s) - sorption , desorption , adsorption , particle (ecology) , chemistry , environmental chemistry , diffusion , work (physics) , hexachlorobenzene , thermodynamics , organic chemistry , pollutant , geology , oceanography , physics
Recent long‐term adsorption and desorption experiments with hexachlorobenzene and three polychlorinated biphenyl congeners have clearly demonstrated that the rates of adsorption and desorption for hydrophobic organic chemicals to natural suspended sediments can be relatively slow and therefore that the assumption of chemical equilibrium may not be valid in many realistic situations. These experiments have also led to a better understanding of the adsorption, desorption, and partitioning processes. Based on this experimental work, a theoretical model of the adsorption, desorption, and partitioning of hydrophobic organic chemicals to suspended sediments has been developed. In the present article, a description of this model is given, and results of numerical calculations using this model are compared with experimental results. In the modeling, the emphasis is on the dynamics of sorption. The model is relatively simple, with retarded chemical diffusion within the particle/floc as the basic transport process. A complicating factor is the variations in the particle/floc size and density distributions; these distributions are dependent on local conditions and may also vary with time. In the modeling, they were chosen on the basis of measurements taken during the sorption experiments. In general, good agreement between the numerical and experimental results was obtained for all cases considered.