Sorption Kinetics of Micropollutants from Suspended Particles: Experimental Observations and Modeling

Abstract

Desorption rates of heavy metals (Zn, Cd, Cu and Pb) and polycyclic aromatic hydrocarbons (phenanthrene, anthracene, fluoranthene, pyrene and benzo(a)pyrene) from natural suspended sediment particles to water were measured experimentally. The amounts cumulatively recovered by desorption were compared to total amounts that could be measured by means of standard analytical methods. Both the metals and the PAH were completely released in 100 days. The observed desorption rates could not be described by simple pseudo first-order kinetics. During the first days desorption rates equivalent to first-order rate constants of approximately 10-2 hr-1 were observed. At the final stage of the desorption process these apparent rate constants were very much lower.