Preliminary study on the photocatalytic degradation of PCDDs in alpha propylene glycol solution

Polychlorinated dibenzodioxins (PCDDs) are a class of notorious persistent organic pollutants (POPs). In this paper, the photocatalytic degradation effects of two typical dioxin compounds including 1,2,7,8-tetrachlorodibenzo-p-dioxin (1,2,7,8-TCDD) and 1,2,4,6,7,9-hexachlorodibenzo-p-dioxin (1,2,4,6,7,9-HxCDD) were studied under the irradiation of 500 nm UV light at room temperature by using multi-functional photochemical reactor when alpha propylene glycol was selected as the carrier solvent. The results showed that the photocatalytic degradation is a highly efficient, energy-saving and potential method for PCDDs. And alpha propylene glycol is a favorable solvent to photocatalytic degradation of PCDDs. The degradation efficiencies of PCDDs varied by time and degradation rate could reach 95% after 75 min irradiation. During the photocatalytic degradation of high chlorinated PCDDs, some low chlorinated dioxins could be detected. The results suggested that the possible mechanism of photolysis of PCDDs was reductive dechlorination. The further research should be carried out.