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Electrocatalytic debromination of BDE-47 at palladized graphene electrode

Hongtao YU, Bin MA, Shuo CHEN, Qian ZHAO, Xie QUAN, Shahzad AFZAL

《环境科学与工程前沿（英文）》 2014年第8卷第2期页码 180-187 doi: 10.1007/s11783-013-0552-x

摘要： Graphene electrodes (Ti/Gr) were prepared by depositing Gr sheets on Ti substrate, followed by an annealing process for enhancing the adhesion strength. Electrochemical impedance spectroscopies and X-ray diffraction patterns displayed that the electrochemical behavior of Ti/Gr electrodes can be improved due to the generation of TiO layer at Ti-Gr interface during the annealing process. The palladized Gr electrodes (Ti/Gr/Pd) were prepared by electrochemical depositing Pd nanoparticles on Gr sheets. The debromination ability of Ti/Gr/Pd electrodes was investigated using BDE-47 as a target pollutant with various bias potentials. The results indicated that the BDE-47 degradation rates on Ti/Gr/Pd electrodes increased with the negative bias potentials from 0 V to -0.5 V (vs. SCE). Almost all of the BDE-47 was removed in the debromination reaction on the Ti/Gr/Pd electrode at -0.5 V for 3 h, and the main product was diphenyl ethers, meaning it is promising to debrominate completely using the Ti/Gr/Pd electrode. Although the debromination rate was slightly slower at -0.3 V than that under -0.5 V, the current efficiency at -0.3 V was higher, because the electrical current acted mostly on BDE-47 rather than on water.

关键词： graphene palladium debromination BDE-47

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Enhanced debromination of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) by zero-valent zinc with ascorbic

Chaojin Jiang, Xiaoqian Jiang, Lixun Zhang, Yuntao Guan

《环境科学与工程前沿（英文）》 2020年第14卷第3期 doi: 10.1007/s11783-020-1224-2

摘要： Highly efficient debromination of BDE-47 was achieved in the ZVZ/AA system. BDE-47 debromination by the ZVZ/AA can be applied to a wide range of pH. AA inhibits the formation of (hydr)oxide and accelerates the corrosion of ZVZ. Reduction mechanism of BDE-47 debromination by the ZVZ/AA system was proposed. A new technique of zero-valent zinc coupled with ascorbic acid (ZVZ/AA) was developed and applied to debrominate the 2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47), which achieved high conversion and rapid debromination of BDE-47 to less- or non-toxic forms. The reaction conditions were optimized by the addition of 100 mg/L ZVZ particles and 3 mmol/L AA at original solution pH= 4.00 using the solvent of methanol/H2O (v:v= 4:6), which could convert approximately 94% of 5 mg/L BDE-47 into lower-brominated diphenyl ethers within a 90 min at the ZVZ/AA system. The high debromination of BDE-47 was mainly attributed to the effect of AA that inhibits the formation of Zn(II)(hydr)oxide passivation layers and promotes the corrosion of ZVZ, which leads to increase the reactivity of ZVZ. Additionally, ion chromatography and gas chromatography mass spectrometry analyses revealed that bromine ion and lower-debromination diphenyl ethers formed during the reduction of BDE-47. Furthermore, based on the generation of the intermediates products, and its concentration changes over time, it was proposed that the dominant pathway for conversion of BDE-47 was sequential debromination and the final products were diphenyl ethers. These results suggested that the ZVZ/AA system has the potential for highly efficient debromination of BDE-47 from wastewater.

关键词： 2 2′ 4 4′-tetrabromodiphenyl ether (BDE-47) Ascorbic acid Reductive debromination Zero-valent zinc

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Effect of humic acid and metal ions on the debromination of BDE209 by nZVM prepared from steel pickling

Yuling CAI,Bin LIANG,Zhanqiang FANG,Yingying XIE,Eric Pokeung TSANG

《环境科学与工程前沿（英文）》 2015年第9卷第5期页码 879-887 doi: 10.1007/s11783-014-0764-8

摘要： As a promising in situ remediation technology, nanoscale zero-valent iron (nZVI) can remove polybrominated diphenyl ethers such as decabromodiphenyl ether (BDE209) effectively, However its use is limited by its high production cost. Using steel pickling waste liquor as a raw material to prepare nanoscale zero-valent metal (nZVM) can overcome this deficiency. It has been shown that humic acid and metal ions have the greatest influence on remediation. The results showed that nZVM and nZVI both can effectively remove BDE209 with little difference in their removal efficiencies, and humic acid inhibited the removal efficiency, whereas metal ions promoted it. The promoting effects followed the order Ni >Cu >Co and the cumulative effect of the two factors was a combination of the promoting and inhibitory individual effects. The major difference between nZVM and nZVI lies in their crystal form, as nZVI was found to be amorphous while that of nZVM was crystal. However, it was found that both nZVM and nZVI removed BDE209 with similar removal efficiencies. The effects and cumulative effects of humic acid and metal ions on nZVM and nZVI were very similar in terms of the efficiency of the BDE209 removal.

关键词： steel pickling waste liquor nanoscale zero-valet metal nanoscale zero-valent iron humic acid metal ion

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Removal of decabromodiphenyl ether (BDE-209) by sepiolite-supported nanoscale zerovalent iron

Rongbing FU,Na MU,Xiaopin GUO,Zhen XU,Dongsu BI

《环境科学与工程前沿（英文）》 2015年第9卷第5期页码 867-878 doi: 10.1007/s11783-015-0800-3

摘要： Nanoscale zerovalent iron (nZVI) synthesized using sepiolite as a supporter was used to investigate the removal kinetics and mechanisms of decabromodiphenyl ether (BDE-209). BDE-209 was rapidly removed by the prepared sepiolite-supported nZVI with a reaction rate that was 5 times greater than that of the conventionally prepared nZVI because of its high surface area and reactivity. The degradation of BDE-209 occurred in a stepwise debromination manner, which followed pseudo-first-order kinetics. The removal efficiency of BDE-209 increased with increasing dosage of sepiolite-supported nZVI particles and decreasing pH, and the efficiency decreased with increasing initial BDE-209 concentrations. The presence of tetrahydrofuran (THF) as a cosolvent at certain volume fractions in water influenced the degradation rate of sepiolite-supported nZVI. Debromination pathways of BDE-209 with sepiolite-supported nZVI were proposed based on the identified reaction intermediates, which ranged from nona- to mono-brominated diphenylethers (BDEs) under acidic conditions and nona- to penta-BDEs under alkaline conditions. Adsorption on sepiolite-supported nZVI particles also played a role in the removal of BDE-209. Our findings indicate that the particles have potential applications in removing environmental pollutants, such as halogenated organic contaminants.

关键词： sepiolite-supported nanoscale zerovalent iron decabromodiphenyl ether debromination adsorption mechanism

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Effective remediation of organic-metal co-contaminated soil by enhanced electrokinetic-bioremediation process

Fu Chen, Qi Zhang, Jing Ma, Qianlin Zhu, Yifei Wang, Huagen Liang

《环境科学与工程前沿（英文）》 2021年第15卷第6期 doi: 10.1007/s11783-021-1401-y

摘要： Abstract • A new EK-BIO technology was developed to decontaminate e-waste contaminated soil. • Adding sodium citrate in electrolyte was a good choice for decontaminating the soil. • The system has good performance with low cost. This work investigates the influence of electrokinetic-bioremediation (EK-BIO) on remediating soil polluted by persistent organic pollutants (POPs) and heavy metals (mainly Cu, Pb and Ni), originated from electronic waste recycling activity. The results demonstrate that most of POPs and metals were removed from the soil. More than 60% of metals and 90% of POPs in the soil were removed after a 30-day EK-BIO remediation assisted by citrate. A citrate sodium concentration of 0.02 g/L was deemed to be suitable because higher citrate did not significantly improve treatment performance whereas increasing dosage consumption. Citrate increased soil electrical current and electroosmotic flow. After remediation, metal residues mainly existed in stable and low-toxic states, which could effectively lower the potential hazard of toxic metals to the surrounding environment and organisms. EK-BIO treatment influenced soil microbial counts, dehydrogenase activity and community structure.

关键词： Electrokinetic Co-contamination Debromination