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 mois t airstream on pretreated fly ash were studied in a laboratory pilot p lant with temperature ranging from 200 to 350 degrees C and reaction t imes varying from 15 to 240 min. The mathematical treatment of experim ental data indicated that two reaction pathways, decomposition and dec hlorination, operated independently because of a partition of the reag ents 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 fi rst-order series reactions. Here, the kinetic scheme for the first two dechlorination steps is discussed. Kinetic constants and partition co nstants at different temperatures as well as Arrhenius and Eyring para meters and the isosteric enthalpy of adsorption are calculated.