Effects of oxygen on formation of PCB and PCDD/F on extracted fly ash in the presence of carbon and cupric salt

The effect of oxygen–nitrogen atmosphere (N2+10%O2,N2+1%O2 and 99.999% N2) on the formation of PCB, PCDD and PCDF by the de novo synthetic reactions in the system consisting of extracted fly ash (from municipal waste incinerators – MWI), activated carbon, CuCl2 · 2H2O and NaCl at 340°C was studied. The content of PCDD/F for systems with 10% O2,1%O2 and 99.999% N2 was decreasing and corresponded to 17304, 5544, and 1437 ng/sample. In all studied systems the isomer OCDD/F was prevailing. The content of PCBs in the same system was also decreasing from 1214 to 166 ng/g. Formation of nonortho PCB was relatively high compared to the system where only nitrogen was present. The possible mechanism of formation is outlined.