Applicability of a Dual-Equilibrium Desorption Model to the Desorption of Organic Compounds from the Sediments in China Rivers

Soil contamination is an enormous problem in China and severely threatens environmental quality and food safety. Desorption of contaminants from soil is a critical process controlling the availability of soil contaminants and thus the risk associated with contaminated soil. All the currently adopted desorption models greatly simplify desorption by assuming that desorption is a simple reverse of adsorption. However, numerous studies have shown that desorption is indeed biphasic. A new dual-equilibrium desorption (DED) model to account for the biphasic desorption has been developed and tested using a wide range of laboratory data. In this paper, field data of major rivers in China were modeled with the DED isotherm and the linear isotherm. Results in the present study indicate that the DED model can more accurately quantify desorption of contaminants from soil and sediments, which proposed the application of the dual-equilibrium desorption model.