Reductive Debromination of Polybrominated Diphenyl Ethers: Dependence on Br Number of the Br-Rich Phenyl Ring

Abstract

Reductive debromination has been widely studied for the degradation of polybrominated diphenyl ethers (PBDEs), although the reaction mechanisms are not so clear. In the present study, the photocatalytic degradation and debromination of ten PBDEs were carried out with CuO/ TiO 2 nanocomposites as the photocatalyst under an anaerobic condition. The pseudo-first-order rate constants were obtained for the photocatalytic debromination of PBDEs, and their relative rate constants (k R ) were evaluated against k R = 1 for BDE209. Unlike the generally accepted summary that k R is dependent on the total Br number (N) of PBDEs, k R is found to depend on the Br number on a phenyl ring with more Br atoms than the other one. In other words, a phenyl ring substituted by more Br is more reactive for the reductive debromination. The calculated LUMO energies (E LUMO ) of all PBDEs are well correlated to the more reactive phenyl ring with more Br, compared with the N of two phenyl rings. The result was explained by LUMO localization on the Br-rich phenyl ring, suggesting that the reductive debromination occurs on the phenyl ring.

Polybrominated diphenyl ethers in water, suspended particulate matter, and sediment of reservoirs and their tributaries in Shenzhen, a mega city in South China

“…2.4 Quality assurance/control (QA/QC) and data analysis Quantitative measurements were executed using a standard addition method based on six concentration levels (1,2,5,10,20,50 ng/mL) for target compounds. Recoveries of 12 PBDEs in spiked water and sediment samples were 75 ~ 94% at 2 ~ 50 ng/L and 77 ~ 90% at 5 ~ 25 ng/g, respectively (Table S6).…”

“…Signi cant correlations (p < 0.05) were also observed between BDE-71, -66 and BDE-85, -138 and BDE-99, -153 and BDE-190, -209 in Wet_s, BDE-47, -85, -190 and BDE-71, -209 in Wet_SPM, suggesting that some low brominated PBDEs may be the degradation products of high brominated ones, e.g. BDE-99, -153 were degradation products of -190(Huang et al, 2019) and BDE-71 was degradation product of -209(Guo et al, 2019). Overall, the possible sources of PBDEs may be associated to the consumption of commercial penta-BDEs (DE-71 and Bromkal 70-5DE: BDE-47, -66, -71, -85, -99 and − 100), octa-BDEs (Bromkal 79-8DE and DE-79: -138, -153 and − 154) and deca-BDEs (Saytex 102E and Bromkal 82-0DE: BDE-209, -190 and − 183) (Bi et al, 2018; Liang et al, 2019; Luo et al, 2020; Mark J.…”

Enhanced Photocatalytic Dehalogenation Performance of RuDoped In2O3 Nanoparticles Induced by Oxygen Vacancy

“…[1,2]. Recently, an increasing amount of research has reported that these kinds of aryl halides, as a series of endocrine hormones, have high toxicity, environmental persistence and bioaccumulation potential, which might pose significant harm to humans and animals [3][4][5][6][7][8]. In order to control pollution due to brominated flame retardants, various technologies have been developed.…”

Aerobic Degradation Characteristics and Mechanism of Decabromodiphenyl Ether (BDE-209) Using Complex Bacteria Communities

“…However, these physical or chemical methods still have some problems that have not been well solved. For example, photocatalytic reduction, nano-zero valent iron and iron-based bimetallic materials have been used for the elimination of BDE-209 [ 21 , 22 , 23 ]; however, most of the reduction processes were incomplete and could produce low-brominated poly brominated diphenyl ethers (PBDEs) congeners, which were even more toxic and difficult to be degraded. As an effective and environmentally friendly approach, biodegradation has been considered a promising technology and one of the most ideal methods for BDE-209 in situ remediation.…”