Mechanism and products of the photolysis of hexabromocyclododecane in acetonitrile–water solutions under a UV-C lamp

Yu, Yingtan; Zhou, Danna; Wu, Feng

doi:10.1016/j.cej.2015.07.031

Cited by 29 publications

(9 citation statements)

References 39 publications

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“…Compared with SO 3 •– , SO 5 •– has a moderate oxidative ability. , Residual As(III) oxidation in the presence of EtOH could be attributed to SO 5 •– . By using a competitive kinetics method (Figure S16), the second-order rate constant for the reaction between SO 5 •– and As(III) is determined to be 1.2 × 10 6 M –1 s –1 , which is large enough for As(III) oxidation in the ES process.…”

Section: Resultsmentioning

confidence: 99%

Metal-Free Electro-Activated Sulfite Process for As(III) Oxidation in Water Using Graphite Electrodes

Luo

Peng

Chen

et al. 2020

Environ. Sci. Technol.

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Transition-metal-activated sulfite [S(IV)] processes for water decontamination have recently received intense attention in the field of decontamination by advanced oxidation processes (AOPs). However, the drawback with respect to the secondary metal sludge contamination involved in various AOPs has been argued often. In this work, we developed a novel electro-sulfite (ES) process using stable and low-cost graphite electrodes to address that concern. Arsenite [As(III)] was used as the target compound for removal by the ES process because of its wide presence and high toxicity. Parameters, including cell voltage, S(IV) concentration, solution pH, and water matrix, and the mechanisms for reactions on anode and cathode were investigated in electrolytic cells containing one or two compartments, respectively. The results show that the ES process using 1 mM S(IV) and 2 V cell voltage oxidizes 5 μM As(III) at a rate of 0.127 min–1, which is 15-fold higher than mere electrolysis without S(IV) addition (0.008 min–1) at pH 7. Further studies using radical scavengers and electron spin resonance assays demonstrated that oxysulfur radicals (i.e., SO5 •– and SO4 •–) and HO• are responsible for As(III) oxidation in the ES process. However, HO2 • produced via the oxygen reduction reaction in the EO process plays a major role in As(III) oxidation, which explains the lower reaction rate in the absence of S(IV). The effectiveness of the ES process was moreover evidenced by 60–82% As(III) oxidation in field water within 40 min. Overall, this work realizes the metal-free activation of S(IV) and significantly leverages the S(IV)-based water treatment technologies.

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Section: Resultsmentioning

confidence: 99%

Metal-Free Electro-Activated Sulfite Process for As(III) Oxidation in Water Using Graphite Electrodes

Luo

Peng

Chen

et al. 2020

Environ. Sci. Technol.

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“…The removal rates of SW and SWLB were higher than SW-C and SWLB-C, indicated that the presence of strain stu-38 could facilitate the removal of HBCDs, which was corresponding to other research (Huang et al 2019). Chemical and physical factors can lead to abiotic transformation of HBCDs, for example, FeS, nanoscale zero-valent aluminum, sul dated nanoscale zerovalent iron, and ultraviolet light (Franke et al 2017;Palau et al 2017;Yu et al 2015). Abiotic transformation of HBCDs could have been mediated by chemicals since the cultures were placed in the dark environment.…”

Section: Discussionmentioning

confidence: 65%

“…The debromination pathways of HBCDs include HBr-elimination (dehydrobromination), HBrdihaloelimination and hydrolytic debromination (Ang et al 2018;Yu et al 2015). HBr-elimination of HBCDs yields lower brominated compounds with an HBr removed to form a carbon-carbon double bond (Kunze et al 2017).…”

Section: The Formation Of the Debrominated Productsmentioning

confidence: 99%

Biotransformations of HBCDs by Rhodococcus Strain Stu-38 and Identification of Transformation Products

Yu¹,

Luo²,

Li³

et al. 2021

Preprint

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1, 2, 5, 6, 9, 10-Hexabromocyclododecanes (HBCDs) are new brominated flame retardants causing serious environmental pollution. Dozens of degradative bacteria have been found with capacity to transform HBCDs. In the present study, an aerobic functional bacterium Rhodococcus strain stu-38 was isolated from enriched culture of mangrove sediment using HBCDs as carbon source. This strain could stereoselectively transform HBCDs, the removal rate was α-＞γ-＞β-HBCD in the mineral salt medium, but was β-＞α- and γ-HBCD in the growth medium, and it selectively transformed γ- HBCD in the seawater. Transformation rate of strain stu-38 was lower than other functional strains, however, seven potential debrominated products of HBCDs were identified by using GC-MS. These debrominated products, included dibromocyclododecadiene, bromocyclododecadienol and bromocyclododecatriene were formed through reductive debromination, hydrolytic debromination and dehydrobromination. Overall, Rhodococcus sp. stu-38 diastereoisomer-specifically transformed HBCDs to various debrominated products in the different cultural media, which highlighted the complicated stereoselective biotransformation of HBCDs.

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“…To elucidate the mechanisms of photocatalytic and photoelectrocatalytic degradation for BPB by the prepared GR/β-CD composite on titanium mesh, 4-BQ (scavenger for O 2 ˙ − , 1.0 mM), 38 isopropanol (scavenger for ˙OH, 0.5 mM), 39 EDTA-2Na (scavenger for the hole, 0.5 mM), 40 and methanol (transforming agent for ˙OH to ˙HO 2 /O 2 ˙ − , 1.0 mM) 41 were added into BPB solutions, respectively.…”

Section: Methodsmentioning

confidence: 99%

Efficient photoelectrocatalytic performance of beta-cyclodextrin/graphene composite and effect of Cl⁻in water: degradation for bromophenol blue as a case study

et al. 2021

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Mechanism and products of the photolysis of hexabromocyclododecane in acetonitrile–water solutions under a UV-C lamp

Cited by 29 publications

References 39 publications

Metal-Free Electro-Activated Sulfite Process for As(III) Oxidation in Water Using Graphite Electrodes

Metal-Free Electro-Activated Sulfite Process for As(III) Oxidation in Water Using Graphite Electrodes

Biotransformations of HBCDs by Rhodococcus Strain Stu-38 and Identification of Transformation Products

Efficient photoelectrocatalytic performance of beta-cyclodextrin/graphene composite and effect of Cl⁻in water: degradation for bromophenol blue as a case study

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Mechanism and products of the photolysis of hexabromocyclododecane in acetonitrile–water solutions under a UV-C lamp

Cited by 29 publications

References 39 publications

Metal-Free Electro-Activated Sulfite Process for As(III) Oxidation in Water Using Graphite Electrodes

Metal-Free Electro-Activated Sulfite Process for As(III) Oxidation in Water Using Graphite Electrodes

Biotransformations of HBCDs by Rhodococcus Strain Stu-38 and Identification of Transformation Products

Efficient photoelectrocatalytic performance of beta-cyclodextrin/graphene composite and effect of Cl−in water: degradation for bromophenol blue as a case study

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Efficient photoelectrocatalytic performance of beta-cyclodextrin/graphene composite and effect of Cl⁻in water: degradation for bromophenol blue as a case study