Aquatic photolysis of hydroxylated polybromodiphenyl ethers under direct UV irradiation: a case study of 2′-HO-BDE-68

Abstract

Hydroxylated polyhalodiphenyl ethers (HO-PXDEs) have attracted considerable scientific interest as examples of emerging aquatic pollutants. However, a comprehensive assessment of disposal methods for this particular pollutant was seldom investigated. This study examined the UV light degradation of HO-PXDEs, using 2′-HO-2, 3′, 4, 5′-tetrabromodiphenyl ether (2′-HO-BDE-68) as a case study. The results showed that UV light was superior to visible light and electron beam irradiation for producing a high degradation rate of 2′-HO-BDE-68. At low concentrations of HO-BDE, the degradation rate was not obviously improved with decreasing initial concentration. The degradation efficiency was also found to be better in alkaline solutions. In a UV/H₂O₂ system, the hydroxyl radical provided by H₂O₂ was shown to enhance the degradation efficiency. The main photolysis products of 2′-HO-BDE-68 were identified, and the possible photodegradation pathways were proposed. 1, 3, 8-Tribromodibenzo-p-dioxin was one of the photoproducts, which indicates that secondary pollution must also be considered with the UV photolysis process.

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