Sorption and desorption rate comparisons for 1,2-dichlorobenzene to a peat soil

Abstract

Abstract The rates of sorption and desorption were quantified for 1,2-dichlorobenzene to and from a peat soil using a batch methodology. Solute—sorbent contact times of 2, 7, 14, 49, and 99 d were studied for the desorption rate experiments. The experimental data were simulated using a distributed rate parameter model. The optimal model fitting parameters and their 95% confidence intervals were computed. The rates of desorption were significantly slower than the rate of uptake for solute–sorbent contact times greater than 2 d. For contact times greater than 2 d, a significant fraction of the 1,2-dichlorobenzene seemed to be irreversibly sorbed. However, the rate of desorption and the magnitude of the irreversible fraction were independent of contact time for contact times greater than 2 d. The rate observations for this study were consistent with an intraorganic matter diffusion mechanism.