DEGRADATION OF OCTACHLORODIBENZOFURAN AND OCTACHLORODIBENZO-P-DIOXIN SPIKED ON FLY-ASH - KINETICS AND MECHANISM

Octachlorodibenzofuran (OCDF)degradation kinetics in a moist nitrogen stream and those of octachlorodibenzo-p-dioxin (OCDD) in a dry or moist airstream on pretreated fly ash were studied in a laboratory pilot plant with temperature ranging from 200 to 350 degrees C and reaction times varying from 15 to 240 min. The mathematical treatment of experimental data indicated that two reaction pathways, decomposition and dechlorination, operated independently because of a partition of the reagents in the fly ash according to a physical and a chemical adsorption. The decomposition reaction was of the first order with respect to the reactant adsorbed physically. The dechlorination reaction involved first-order series reactions. Here, the kinetic scheme for the first two dechlorination steps is discussed. Kinetic constants and partition constants at different temperatures as well as Arrhenius and Eyring parameters and the isosteric enthalpy of adsorption are calculated.