Photooxidation of exhaust pollutants—V. Photooxidation and photoreduction of polychlorinated dibenzo-p-dioxins and dibenzofurans on fly-ash

The photochemical decomposition of polychlorinated dibenzo-p-dioxins and dibenzofurans was investigated on fly-ash particles from municipal solid waste. Photodegradation experiments were performed in the solid phase by direct irradiation with medium and low pressure mercury lamps in an oxygen/ozon atmosphere under oxidizing conditions and in an nitrogen/ammonia atmosphere under reductiv conditions. Qualitative and quantitative analysis was performed by GC/MS-spectroscopy. The degradation efficiency mainly depends on the effective irradiation time but also on the reaction temperature and to a small degree on the power output of the UV-lamp. The degradation rates were investigated in special reaction chambers under different conditions and with various additives and lead to a maximum value of about 70%.