Formation of aromatic chlorinated compounds catalyzed by copper and iron

This study shows the catalyzing effects of iron and copper on the formation of chlorinated compounds such as chlorobenzenes (ClBzs), chlorophenols (CIPhs), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). Both total concentrations and congener distributions have been studied. The parameters and conditions varied during the combustion tests were the complete and incomplete combustion and the metal and chlorine addition. The incomplete combustion promoted the formation of organic chlorinated compounds in flue gas particles. Highly chlorinated congeners of PCDD/F were dominant in the flue gas particles, whereas the importance of lower chlorinated congener were increased in the gas phase. In the complete combustion conditions the concentrations of PCDD/Fs increased when the degree of chlorination were high, nevertheless the concentrations of tetra and penta PCDD/Fs were higher in the gas phase than the concentrations in the fly ash particles. Organic chlorine promoted the formation of chlorinated compounds more effectively than inorganic chlorine, which instead promoted the formation of PCDD/Fs in the gas phase, especially with copper catalyst. Different concentration levels of chlorinated compounds were observed in the gas phase and in particles when the chlorine source and combustion conditions were varied from incomplete to optimum conditions. Both copper and iron seem to have a catalytic effect on PCDD/F formation.