Kinetics of phenanthrene desorption from activated carbons to water

We determined the kinetics of phenanthrene desorption from three activated carbons to water using Tenax beads as an infinite sink for organic compounds in water. Desorption kinetic data very well fitted a biphasic kinetic model based on the presence of two different adsorption sites, viz. low-energy sites and high-energy sites. Rate constants for desorption to water from these two types of sites in the three activated carbons did not reveal a relation with activated carbon grain size. These rate constants were comparable to those for desorption of various organic compounds from hard carbon in various sediments.