CHEMOSPHERE
·
2022
·
IF 8.943
Zhengnan Tu,Yumeng Qi,Ruijuan Qu,Xiaosheng Tang,Zunyao Wang,Zongli Huo
As one of the first batch of persistent organic pollutants (POPs) included in Stockholm Convention , hexachlorobenzene (HCB) has attracted great attention because of its wide occurrence and great environmental risks. Considering the easy adsorption of HCB on solids and the complexity of natural particles, we systematically investigated the photodegradation of HCB on the surface of silica gel (SG) in aqueous solution in this work to reveal its fate in natural waters. Under mercury lamp irradiation, more than 90% of HCB loaded on SG could be removed after 240 min. Moreover, the effects of solution pH and water constituents were examined, and results showed that the presence of NO 2 − , NO 3 − , Fe 3+ and humic acid (HA) significantly inhibited the reaction due to the scavenging of ROS and/or competitive absorption of light. According to radical quenching experiments and electron paramagnetic resonance (EPR) spectra, hydroxyl radicals and singlet oxygen generated on the surface of SG could participate in the transformation of HCB, but •OH played a dominant role. Based on products identified by high performance liquid chromatography-mass spectrometry (HPLC-MS) and gas chromatography-mass spectrometry (GC-MS), two main pathways were proposed for the removal of HCB, including dechlorination and hydroxylation which represent direct and indirect photodegradation, respectively, and the occurrence of these two reactions was further supported by density functional theory (DFT) calculations. From the quantitative analysis of penta-chlorobenzene, it was estimated that dechlorination and hydroxylation contributed to approximately 44.4% and 55.6% of initial HCB degradation, respectively. Furthermore, toxicity predictions by the ecological structure–activity relationship model (ECOSAR) suggested that the toxicity of HCB was decreased in the photodegradation process. This study would provide important information for understanding the photochemical transformation mechanism of HCB at the solid/water interface.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2022
·
IF 8.943
Zhenzhen Yao,Xiaoman He,Qian Wang,Chao Wang,Qing Shi,Qiwu Zhang
This study explored a possible destruction of hexachlorobenzene (HCB) as example of persistent organic pollutants (POPs) as well as the dechlorination mechanism by directly using minerals in the soil, such as antigorite , talc and olivine. Compared with a stable quartz phase of SiO 2 , all three Mg silicate minerals demonstrated certain degrading capacity for HCB with different efficiency order as: antigorite > talc > olivine > SiO 2 at 2 h of milling time. Interestingly, olivine exhibited a better performance than antigorite at 4 h of milling time, giving destruction percentage of 92.7% over 89.0% even at high concentrated HCB up to 5% added. Raman and ESR characterizations of the ball milled sample with olivine indicated the formation of amorphous carbon and graphitic carbon, and the occurrence of free radicals was observed to play an important role in dechlorination and carbonization of HCB. The first identified effectiveness of directly using Mg silicate minerals, allowed no addition of active chemicals during the ball milling, therefore avoided the concern over extrinsic contaminations on the soil. Olivine was further utilized to deal with actual contaminated soil and showed unique advantages on application prospects.
研究领域:
环境科学
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化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2023
·Vol. 30
·期 14
·41910-41922
·
IF 5.8
Li Xue,Chen Huichao
The use of mechanochemistry for the remediation of hexachlorobenzene (HCB)-contaminated soil was investigated. Additives such as alkaline materials, neutral materials, natural minerals, and solid waste were studied to explore their effect on the degradation of hexachlorobenzene in soil with single or combined addition by mechanochemical method. The best combination of materials were determined based on HCB destruction percentage by considering the impact on soil quality, the treatment cost, and the availability of additives. Scanning electron microscope (SEM) images and X-ray photoelectron spectrometer (XPS) analysis were conducted for the mechanism studies. The combination of albite and ferric oxide (Fe 3 O 4 ) was found to achieve the best performance in the degradation of HCB with the destruction percentage from 74.3 to 92.5% after 2-h and 6-h reaction, respectively. The developed fracture structure and complex compositions of albite provided abundant reaction sites for mechanochemical degradation of HCB in soil.
研究领域:
环境科学
·
土壤修复
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY
·
2010
·Vol. 86
·期 1
·38-42
·
IF 0.992
Yang Zhong-Zhi,Li Yong-Fang,Li Zhi-Chun,Gu Yu-Mei,Zhu Ya,Zhang Zhan-Jun
Five higher Chlorinated Benzenes (CBs), include Hexachlorobenzene (HCB), pentachlorobenzene (PeCB) and three isomers of tetrachlorobenzens, were analyzed in 20 outdoor dust samples collected from a fast developing city, Xinxiang. Only HCB was detected in all outdoor dust samples. The dominate part of the CBs residue in most samples was HCB and the mean HCB concentration (4.13 ng/g dry weight) in this study was in the range of global background soil HCB levels (ranging from 0.010 to 5.20 ng/g dry weight). The higher ratios of HCB/PeCB in the outdoor dust samples in the present study indicate that pesticide application may be an important source of HCB in China.
研究领域:
环境科学
·
毒理学
✓ 已验证
DOI
PubMed
高影响因子
Desalination and Water Treatment
·
2016
·
IF 1.272
Wei-Fang Chen,Weiya Wang,Jinghui Zhang,Xiaomao Zhang,Yuxiang Li
Activated carbon, nano zerovalent iron (nZVI), and nano zerovalent iron/activated carbon (nZVI/AC) have all been found to be effective for hexachlorobenzene (HCB) removal either through adsorption, dechlorination, or both. Detailed investigations on the effects of several anions and cations normally present in aqueous streams on the removal of HCB were carried out to evaluate the potential performance of these materials in field treatment. Effects of ions were analyzed from the perspectives of changes in pH, ionic strength, and redox conditions. Results showed that ions that facilitate zerovalent iron corrosion, i.e. bicarbonate, chloride, chloride, ferrous, and copper, could greatly enhance HCB removal by nZVI, while HCB adsorption by activated carbon was more a factor of solution pH and ionic strength. The effects of ions on nZVI/AC were more complicated since both nZVI and activated carbon played a role in HCB removal. The results lead to a better understanding of HCB removal by these materials and could be employed in the consideration of choosing materials and prediction of treatment efficiency.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2024
·
IF 3.5
Zhengyan Wang,Chenhao Yuan,Dong Yang,Mifen Cui,Jihai Tang,Zhuxiu Zhang,Xu Qiao
It is of great significance to develop catalysts for the degradation of hexachlorobenzene from the industrial thermal process. In this paper, formic acid was used as a modulator to generate defect sites in Ce/Zr-UiO-66 with intrinsic Brønsted acidity. The defective formate ligands were removed through methanol–water vapor treatment to expose additional open metal sites with Lewis acidity. The intrinsic Brønsted acid sites of the resulting Ce/Zr-UiO-66-FA-P achieved a hexachlorobenzene degradation efficiency of 99.5% at 250 °C. The generated Lewis acid sites facilitated the C–C cleavage of degradation intermediates. More than 95.0% of the final products were CO2/CO, coupled with chlorinated alkanes/alkenes, which outperformed other benchmark metal oxide catalysts. The Ce/Zr-UiO-66-FA-P catalyst maintained its catalytic activity in the model industrial flue gas and humid environment. The degradation pathway of hexachlorobenzene was tracked using in situ FT-IR spectra.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2016
·
IF 3.698
Yingjie Li,Qingnan Liu,Wenfeng Li,Yingzhou Lu,Hong Meng,Chunxi Li
Mechanochemical destruction (MCD) is a good alternative to traditional incineration for the destruction of persistent organic pollutants (POPs), like hexachlorobenzene (HCB), and the key is to find an efficient co-milling reagent. Toward this aim, HCB was milled with various reagents in a planetary ball mill at room temperature, and CaC 2 was found to be the best one. HCB can be destroyed completely within 20 min at a mass ratio of CaC 2 /HCB = 0.9 and a rotation speed of 300 rpm. The ground samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy . The results show that the destruction products are nonhazardous CaCl 2 and carbon material with both crystalline and amorphous structures. On these bases, possible reaction pathways were proposed. Considering its excellent efficiency and safety, CaC 2 may be the most feasible co-milling regent for MCD treatment of HCB. Further, the results are instructive for the destruction of other POPs.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Shuyao Yu,Bing Du,Amanjiao Baheiduola,Chao Geng,Jianguo Liu
Municipal solid waste incineration fly ash (MSWI-FA) has been strictly controlled as hazardous waste globally because it contains various heavy metals and dioxins. This study prepared a nanometallic Al/CaO (n-Al/CaO) dispersion mixture via ball-milling as a reductive stabilization reagent for the simultaneous immobilization of heavy metals and detoxification of POPs like substance in MSWI-FA. Under optimal conditions, Cu, Zn, Cd, Cr, Ni, and Pb had been significantly immobilized (over 99.9 %) and the leaching concentration of Zn, Cd, Cr, Ni, and Pb were below the detectable limit. Simultaneously, 82.43 % of HCB can be destructed into alkanes and amorphous carbon. The porous structure of the fly ash and alkaline surface of n-Al/CaO promoted the adsorption and cracking of HCB. The highly active n-Al/CaO interacted with water as the hydrogen donor to promote the reductive dechlorination process. Hydrocalumite was a new mineral formed from the adsorption and complexation of heavy metal. Therefore, n-Al/CaO can strengthen the control of heavy metals in the S/S treatment of MSWI-FA, effectively detoxify chlorinated organics, and reduce environmental health risks.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2018
·
IF 4.61
Jun Hu,Zhiyong Huang,Jianming Yu
In this study, Fe/Fe 3 O 4 mixture was first applied as an additive to achieve the highly-effective mechanochemical destruction (MCD) of two halogenated organic pollutants (HOPs), hexachloroethane (HCE) and hexachlorobenzene (HCB). The MCD of HCE was more effective than that of HCB in virtue of the lower dissociation energy of C Cl bond. The MCD of HOPs occurred mainly via the reduction by Fe, Fe 3 O 4 and Fe/Fe 3 O 4 . The oxidation of Fe 3 O 4 and reduction of FeO (formed on account of the oxidation of Fe by oxygen-containing species) may also contribute to the HOP destruction. Fe/Fe 3 O 4 mixture exhibited a higher dechlorination rate (DR) than other three effective additives (i.e., Fe/SiO 2 , Al/Al 2 O 3 and Mg/Al 2 O 3 mixture), owing to the electrical property of Fe 3 O 4 and its electron transfer with Fe. The HOP destruction was significantly impacted by the mass fraction of Fe 3 O 4 (MF mag ) and achieved the maximum level with an MF mag of 70%. The DR of HOPs in the atmosphere of air was higher than those of pure oxygen and nitrogen because of the oxygen vacancy in Fe 3 O 4 and oxidation of Fe. The presence of water dramatically inhibited the HOP destruction due to the decrease of collision energy and its competition for the active sites in both Fe and Fe 3 O 4 . As expected, the DR of HOPs increased with rotation speed, and the mass ratio of ball to reactant and additive to pollutant. The analysis of intermediates indicates that HCB destruction was mainly via dechlorination and polymerization, while HCl cleavage also played an important role in HCE destruction. The results demonstrate that Fe/Fe 3 O 4 mixture is a suitable additive for MCD process.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 87
·46689-46696
·
IF 3.708
Wei-fang Chen,Ling Pan,Li-fang Chen,Qiong Wang,Chang-cheng Yan
Nano zero-valent iron (nZVI) and activated carbon composites were synthesized and employed to remove hexachlorobenzene (HCB). Methods of impregnation and adsorption were employed to firstly load iron salt onto activated carbon, and thus loaded iron was then reduced to form zero valent iron. Results indicate that the method of iron loading significantly impacted the amount of iron and HCB dechlorination. In general, nZVI/activated carbon composite synthesized using an adsorption method showed considerably higher removal efficiency and dechlorination capability. More than 80% of the HCB was dechlorinated after 48 h. The dechlorination of HCB followed a stepwise pathway: HCB (hexachlorobenzene) → PCB (pentachlorobenzene) → 1,2,4,5 TeCB (tetrachlorobenzene) → TriCB (trichlorobenzene) → 1,4 DCB (dichlorobenzene) → MCB (monochlorobenzene). Compared with activated carbon or nZVI, nZVI/activated carbon composite showed much higher HCB removal. Analysis of mass partition on solid and aqueous phases indicates that most of the HCB and its dechlorination intermediates were retained on solids probably due to the strong adsorption on activated carbon. In summary, activated carbon performs three important functions: it alleviated the limitation of nZVI agglomeration, contributed to HCB removal due to its own adsorption capability and increased the resistance of nZVI against pH change.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2017
·
IF 0
Shengjie Xia,Mengdan Qian,Xiaobo Zhou,Yue Meng,Jilong Xue,Zheming Ni
In this paper, we synthesized five different types of ZnCr layered double hydroxides with different anions (F − , Cl − , Br − , I − and NO 3 − ). A thorough determination of the structure, chemical composition and other physical and chemical properties of the synthesized LDHs materials were done by techniques such as XRD, FTIR, BET, ICP-AES and UV–vis. The photocatalytic degradation of hexachlorobenzene reaction showed that different anions have largely influence on the reactivity and selectivity of the LDHs. The structure stability difference of the LDHs was explained and compared based on the difference of the following physical properties such as Mulliken bonding population, hydrogen bonding and density of states, which were calculated based on DFT theory. It was found that the photocatalytic performance of these LDHs was highly related to their structure stability. In addition, the HCB degradation mechanism was also analyzed by combining GC–MS data and the dissociation energy calculation.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
SENSORS AND ACTUATORS B-CHEMICAL
·
2016
·
IF 4.758
Guangxia Yu,Weina Zhang,Qiang Zhao,Weixiang Wu,Xiaoyun Wei,Qing Lu
Reduction of hexachlorobenzene (HCB) on the surface of nitrogen–doped graphene (NG) and chitosan modified glassy carbon electrode is sensitive in deaerated organic electrolyte solutions using differential pulse voltammetry (DPV). Under optimized conditions, the modified electrode achieved good sensing performances for the detection of HCB, with a wide linear range from 3 μg/L to 10 mg/L, and a low detection limit of 1.72 μg/L. The HCB sensor is constructed by using a layer–by–layer assembly technique. In this sensor, NG not only provides electrocatalytic activity for the reduction of HCB, but also shows good adsorption affinity to HCB, which enhances the sensitivity of sensor. The sensor has been successfully utilized for detection of HCB in practical water samples, providing a promising alternative for the environmental monitoring.
研究领域:
环境科学
·
材料科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）