Influence of Organic Cosolvents on the Sorption Kinetics of Hydrophobic OrganicChemicals

摘要

A quantitative examination of the kinetics of sorption of hydrophobic organicchemicals by soils from mixed solvents reveals that the reverse sorption rate constant k(sub 2) increases log-linearly with increasing volume fraction of organic cosolvent f(sub c). The relationship was expected, based on the existence of a log-log inverse relationship between k(sub 2) and the equilibrium sorption constant K(sub p), and a log-linear inverse relationship between K(sub p) and f(sub c). These results are interpreted in terms of a conceptual model wherein sorption kinetics is controlled by diffusion of sorbate within the matrix of sorbent organic matter. Decreased polarity of the mixed solvent, caused by the addition of a cosolvent, appears to influence the conformation of the polymeric organic matter and, hence, the rate of sorbate diffusion. (Copyright (c) 1991 by the American Chemical Society.)