The Correlation Pattern of Fly Ash Components: Chromium as a Potential Catalyst in the Thermal Formation of Chlorinated Aromatic Compounds

Environmental Context. Harmful chlorinated aromatic molecules are often formed and released into the environment during incineration of municipal waste and other waste fuels. This is a problem that has been known since the 1970s, and while efforts are being made to reduce these emissions, these persistent organic pollutants are still subsequently released into the environment, with residues and emissions to the atmosphere. In an attempt to uncover the chemical agents responsible for the formation of these pollutants, this study reveals that chromium, a commonly encountered metal, could be an important factor.

Abstract. Chlorinated aromatic compounds are unintentionally released from combustion sources into the environment. This thermal formation is catalyzed by fly ash components and much interest has been focussed on the role of copper. This study report results from a series of 16 full-scale trials with different fuel compositions. The correlation pattern of fly ash components seem to suggest that the catalytic effect may be due also to other metal oxychlorination catalysts. Chromium shows particularly strong and statistically significant correlations with many of the chlorinated phenols, benzenes, dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs).