A quantitative examination of the kinetics of sorption of hydrophobic organic chemicals by soils from mixed solvents reveals that the reverse sorption rate constant (k2) increases log-linearly with increasing volume fraction of organic cosolvent (fc). This relationship was expected, based on the existence of a log-log inverse relationship between k2and the equilibrium sorption constant (Kp), and a log-linear inverse relationship between Kpand fc. 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.
ASJC Scopus subject areas
- Environmental Chemistry