Photochemical Degradation of Polybrominated Diphenyl Ethers in Micro Photo-Reactor

Abstract

Polybrominated diphenyl ethers (PBDE) were widely used as flame retardants in plastics. There are highly persistent and bio-accumulative toxicants that came to the attention after their huge quantities had been released into the environment. Due to distinct similarity of PBDE to the polychlorinated biphenyls (PCB), the PBDE present a potential health hazard. In order to decrease the environmental impact of PBDEs and to stop their spread in the food chain the different degradation methods have been investigated. This work is focused on verification and comparison of the various dehalogenation methods of PBDE. In particular, the photochemical degradation reaction pathways of different selected congeners substituted with 1 to 10 bromines, in solvents are examined. Photochemical reaction is a non-invasive method with a high degradation potential. The photochemical reaction is conducted in batch or continuous reactors. Comparison of experimental results based on determination of individual reaction products shows the efficiency of the studied photochemical methods running in both reactor arrangements. New photochemical method employing the photochemical microreactor was investigated that has not been reported in the literature so far. The original experimental results confirm the significantly faster and deeper degradation rate of PBDE's compared to the published results of the photocatalysis over nanoporous TiO 2 in microwave field and the conventional photochemical reactors.