Thermal Degradation of PCDD/Fs Promoted by Alcohol Amines in Different Types of Incinerator Ashes

The low-temperature thermal treatment to degrade PCDD/Fs contained in fly ash was promoted by alcohol amines in a closed system. Three types of fly ash collected separately from municipal solid waste incinerator, medical waste incinerator and hazardous waste incinerator, were compared. Experimental design was used to investigate the homologue patterns of PCDD/Fs and distribution of the toxic congeners in fly ash from incinerator after thermal treatment promoted by alcohol amines. The effect of ethanolamine (MEA) on the hydrodechlorination reaction of polychlorinated aromatics pollutants on fly ash from solid waste incinerator was carried out, and the three ashes clearly showed different degradation potentials for PCDD/F during thermal treatment. Results from the present study indicate that (1) the concentration of alkaline species and metals strongly influenced the degradation of PCDD/F; (2) after addition of 8% MEA, the toxicity equivalent (TEQ) values of PCDD/Fs in fly ash were significantly lower than those obtained without MEA. 49%–71% of PCDD/Fs in TEQ was removed from different types of ash at 250℃ with 8% MEA; (3) the destruction and dechlorination are major mechanism for PCDD/Fs degradation.