Foods
·
2023
·Vol. 12
·期 15
·2875
·
IF 5.2
Yibo Dong,Xiaolong Yao,Wanping Zhang,Xiaomao Wu
3,4-dichloroaniline (3,4-DCA) and 3,5-dichloroaniline (3,5-DCA) are, respectively, the primary metabolites deriving from the breakdown of phenylurea herbicides and dicarboximide fungicides in both soils and plants, whose residues in vegetable products have a heightened concern considering their higher health risks to humans and greater toxicity than the parent compounds in the environment. In this study, a sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the simultaneous determination of 3,4-DCA and 3,5-DCA residues in chive products based on the optimization of HPLC-MS/MS chromatographic and mass-spectrometric conditions using the standard substances and the modified QuEChERS preparation technique. The preparation efficiency of 3,4-DCA and 3,5-DCA from chive samples showed that acetonitrile was the best extractant. The combination of the purification agent graphite carbon black + primary secondary amine and the eluting agent acetonitrile + toluene (4:1,v/v) had a satisfactory purification effect. The linear correlation coefficients (R2) were more than 0.996 with the six concentration range of 0.001–1.000 mg/L for 3,4-DCA and 3,5-DCA. The limit of detection and limit of quantitation of this method was 0.6 and 2.0 µg/kg for 3,4-DCA, as well as 1.0 and 3.0 µg/kg for 3,5-DCA, respectively. The matrix effect range of 3,4-DCA and 3,5-DCA in chive tissues was from −9.0% to −2.6% and from −4.4% to 2.3%, respectively. The fortified recovery of 3,4-DCA and 3,5-DCA in chive samples at four spiked levels of 0.001–1.000 mg/kg was 75.3–86.0% and 78.2–98.1%, with the relative standard deviation of 2.1–8.5% and 1.4–11.9%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) of the method were 0.6, 2.0, and 1.0, 3.03 for 4-DCA and 3,5-DCA, respectively. This study highlights that the analytical method established here can efficiently and sensitively detect residues of 3,4-DCA and 3,5-DCA residues for monitoring chive products. The method was successfully applied to 60 batches of actual vegetable samples from different regions.Keywords:3,4-dichloroaniline;3,5-dichloroaniline;simultaneous determination;UPLC-MS/MS;chive
研究领域:
分析化学
·
食品安全
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2024
·
IF 9.7
Jiahui Zhang,Wenliang Zhang,Yue Wang,Shaoyi Jiang,Yan Wang,Zhezheng Ding,Xiaomin Liu
2,4-dichlorophenoxyacetic (2,4-D) acid and 4-chlorophenoxyacetic acid (4-CPA), as widely utilized organochlorine pesticides , are normally detected in wastewater and atmosphere. Their harmfulness to the ecosystem cannot be ignored. UV/H 2 O 2 is one of the most conventional advanced oxidation processes, which has remarkable advantages for the removal of refractory organic pollutants in wastewater. However, the reaction mechanisms and pathways of pollutants with reactive radicals are still unclear. In this study, the degradation efficacy and mechanisms during the photodegradation of 2,4-D and 4-CPA in UV/H 2 O 2 processes were investigated by experiments and density functional theory calculations. The results showed that 2,4-D was more likely to be degraded by UV/H 2 O 2 treatment than UV photolysis alone. In contrast, 4-CPA can be degraded effectively and rapidly under UV irradiation alone. By LC-MS analysis, the degradation products of 2,4-D and 4-CPA in the UV/H 2 O 2 processes were identified and they were produced by hydroxylation and photolysis. Therefore, we speculated a competition mechanism presented between direct photolysis and indirect photolysis in the UV/H 2 O 2 degradation of 2,4-D and 4-CPA. The OH-initiated reaction mechanisms of 2,4-D and 4-CPA in aqueous environments were investigated using quantum chemical methods SMD/M06–2X/6–311++G (3df, 2p)//SMD/M06–2X/6-311 + G (d,p). The pH dependence of the reaction mechanisms and rate constants in their degradation process induced by ·OH was also investigated. The calculation results showed that the ionic forms (2,4-D - and 4-CPA - ) were more prone to react with ·OH in comparison to the corresponding molecular forms (2,4-D and 4-CPA). The total rate constants of 2,4-D and 4-CPA with OH increased with the pH from 1 to 10, and decreased with continued pH increase. The toxicities of 2,4-D, 4-CPA and their products were assessed by the QSAR-based toxicity evaluation software. The results showed that several products were more toxic than their parent compounds, such as 2,4-dichlorophenol, 3,5-dichlorocatechol, 4-chlorophenol and hydroquinone . This work can contribute to clarifying the environmental risks of 2,4-D and 4-CPA and offer a complete understanding for the photodegradation behavior of 2,4-D and 4-CPA in aqueous ecosystems.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
·
2021
·Vol. 87
·期 6
·
IF 4.792
Minggen Cheng,Dongmei Pei,Xiangrong He,Yongchuang Liu,Pingping Zhu,Xin Yan
The bacterial hydrolytic dehalogenation of 4-chlorobenzoate (4CBA) is a coenzyme A (CoA)-activation-type catabolic pathway that is usually a common part of the microbial mineralization of chlorinated aromatic compounds. Previous studies have shown that the transport and dehalogenation genes for 4CBA are typically clustered as an fcbBAT1T2T3C operon and inducibly expressed in response to 4CBA. However, the associated molecular mechanism remains unknown. In this study, a gene (fcbR) adjacent to the fcb operon was predicted to encode a TetR-type transcriptional regulator in Comamonas sediminis strain CD-2. The fcbR knockout strain exhibited constitutive expression of the fcb cluster. In the host Escherichia coli, the expression of the Pfcb-fused green fluorescent protein (gfp) reporter was repressed by the introduction of the fcbR gene, and genetic studies combining various catabolic genes suggest that the ligand for FcbR may be an intermediate metabolite. Purified FcbR could bind to the Pfcb DNA probe in vitro, and the metabolite 4-chlorobenzyl-CoA (4CBA-CoA) prevented FcbR binding to the Pfcb DNA probe. Isothermal titration calorimetry (ITC) measurements showed that 4CBA-CoA could bind to FcbR at a 1:1 molar ratio. DNase I footprinting showed that FcbR protected a 42-bp DNA motif (5′-GGAAATCAATAGGTCCATAGAAAATCTATTGACTAATCGAAT-3′) that consists of two sequence repeats containing four pseudopalindromic sequences (5′-TCNATNGA-3′). This binding motif overlaps with the −35 box of Pfcb and was proposed to prevent the binding of RNA polymerase. This study characterizes a transcriptional repressor of the fcb operon, together with its ligand, thus identifying halogenated benzoyl-CoA as belonging to the class of ligands of transcriptional regulators.IMPORTANCE The bacterial hydrolytic dehalogenation of 4CBA is a special CoA-activation-type catabolic pathway that plays an important role in the biodegradation of polychlorinated biphenyls and some herbicides. With genetic and biochemical approaches, the present study identified the transcriptional repressor and its cognate effector of a 4CBA hydrolytic dehalogenation operon. This work extends halogenated benzoyl-CoA as a new member of CoA-derived effector compounds that mediate allosteric regulation of transcriptional regulators.
研究领域:
微生物学
·
分子生物学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
Micromachines
·
2022
·Vol. 13
·期 11
·1857
·
IF 3.523
Shisong Yu,Kai Zhang,Xiangcheng Cai,Peng Tu,Yuanming Zhou,Fei Mei
Organic-inorganic perovskite materials are widely used in the preparation of light-emitting diodes due to their low raw material cost, solution preparation, high color purity, high fluorescence quantum yield, continuously tunable spectrum, and excellent charge transport properties. It has become a research hotspot in the field of optoelectronics today. At present, the nonradiative recombination and fluorescence quenching occurring at the interface between the device transport layer and the light-emitting layer are still important factors limiting the performance of perovskite light-emitting diodes (PeLEDs). In this work, based on CH3NH3PbBr3perovskite, the effects of parameters such as precursor solution, anti-solvent chlorobenzene (CB), and small amine molecule phenylmethylamine (PMA) on the performance of perovskite films and devices were investigated. The research results show that adding an appropriate amount of PMA can reduce the grain size of perovskite, improve the coverage of the film, enhance the crystallinity of the film, and increase the fluorescence intensity of the perovskite film. When the PMA content is 0.050 vol.%, the maximum luminance of PeLEDs is 2098 cd/m2and the maximum current efficiency is 1.592 cd/A, which is greatly improved by 30% and 64.8% compared with the reference device without PMA doping. These results suggest that an appropriate amount of PMA can effectively passivate the defects in perovskite films, and inhibit the non-radiative recombination caused by the traps, thereby improving the optoelectronic performance of the device.Keywords:perovskite;phenylmethylamine;chlorobenzene;light-emitting diode
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2024
·
IF 6.7
Xiaoxiao Ding,Yatao Yang,Weihong Jiao,Zequan Zeng,Zhanggen Huang
The heteroatom doping into the activated carbon (AC) has been proved to be one of powerful tools to remove dioxins from sintering flue gas. However, the fact that the intrinsic enhanced mechanism of specific nitrogen species still remains unanswered makes the choice and design of AC suitable for dioxins elimination difficult. Herein, nitrogen-doping AC with alterable N species were prepared by melamine modification to in-depth illuminate the promotional roles of N-containing groups on the adsorption of chlorobenzene (CB) (a model compound for dioxins) over ACs through experimental and density functional theory (DFT). The results demonstrated that the N-doping was obviously conducive to CB adsorption, and pyrrole N group with the strongest adsorption energy (−0.84 eV) between AC-pyrrole and CB was determined to be the key adsorption sites for CB. ACM600 with more pyrrole N group prominently improved the chemical adsorption of total adsorption amount from 8.18 % to 15.12 %. The adsorption mechanism of CB onto ACs was governed by physical adsorption and weak chemical adsorption, which was attributed to the synergistic effects of π-π stacking interaction and hydrogen bonds, and the π-π stacking interaction dominated the adsorption interactions. The introduction of heteroatom N enhanced the adsorption capacity by promoting the chemical reactivity and π-electron density distribution of AC, and forming more significant π-π stacking interaction with the π-acceptor. The study provided a sound theoretical guideline and scientific foundation for the design and estimation of carbonaceous materials for dioxins abatement.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Desalination and Water Treatment
·
2016
·
IF 1.272
Xudong Zheng,Jiangdong Dai,Jianming Pan
In this work, mesoporous attapulgite (mATP) was firstly prepared in the presence of the cetyltrimethylammonium bromide using attapulgite (ATP) as the matrix materials. Then, it was modified by β-cyclodextrin (β-CD) to obtain the β-cyclodextrin/mesoporous attapulgite composites (β-CD/mATP). The characterization of the composites showed that β-CD/mATP composites remained excellent channel structure and the value of the specific surface area was 300.30 m2/g. As-prepared β-CD/mATP was evaluated as sorbents to adsorption of 2,4,6-trichlorophenol (2,4,6-TCP) and 2,4,5-trichlorophenol (2,4,5-TCP). The results of the batch mode experiment revealed that the Langmuir isotherm model fitted the equilibrium data better, while the kinetic data could be described by pseudo-second-order model perfectly. Furthermore, 2,4,5-TCP adsorption onto β-CD/mATP was more affected than that of 2,4,6-TCP in the presence of competitive phenolic compound. In addition, β-CD/mATP possessed excellent regeneration property.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
ADSORPTION SCIENCE & TECHNOLOGY
·
2013
·
IF 0.559
Ping Yu,Qilong Sun,Jianming Pan,Zhenjiang Tan,Jiangdong Dai,Yongsheng Yan,Feng Cheng
Poly(styrene–divinylbenzene)/Fe3O4 (Fe3O4@St–DVB) magnetic porous polymer microspheres based on suspension polymerization were prepared for adsorption of 2, 4-dichlorophenol (2, 4-DCP) and 2, 6-dichlorophenol (2, 6-DCP) from aqueous solution. The as-prepared product was characterized by Fourier transform infrared spectroscopy, Raman, X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, differential thermal analysis and elemental analysis. The results showed that the composite material has both porous and magnetic characteristics, which aid in faster separation and increase in adsorption capacity. The adsorption performance of the Fe3O4@(St–DVB) magnetic porous microspheres was manifested by batch mode adsorption experiments with respect to pH, initial concentration, contact time and temperature. The adsorbent was found to be sensitive to changes in pH, and the adsorption capacity of 2, 4-DCP is higher than that of 2, 6-DCP. The kinetics experimental data fitted well with the pseudo-second-order model, as three steps belonged to the pseudo-second-order adsorption process. The adsorption isotherms were also described by the Langmuir and Freundlich isotherm models, respectively. It was found that the Langmuir isotherm model fitted the equilibrium data superior to the Freundlich model. Thermodynamic parameters were calculated by the Gibbs free energy function, confirming that adsorption process was spontaneous and endothermic. In addition, the reusability performance of the Fe3O4@(St–DVB) magnetic porous microspheres was demonstrated by four repeated cycles.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Lei Yang,Yun Chen,Da Ouyang,Jingchun Yan,Linbo Qian,Lu Han,Mengfang Chen,Jing Li,Mingyue Gu
Nanoscale zero-valent iron (nZVI) supported on rice stalk (RS) derived biochar composite (nZVI/RS) was synthesized as persulfate (PS) activator, achieving efficient adsorptive and catalytically oxidative removal for monochlorobenzene (MCB). Development of porous structures and enhanced aromaticity of RS with increased pyrolysis temperatures promoted MCB adsorption, with removal efficiencies of MCB rising from 11.2% for nZVI/RS300 to 72.3% for nZVI/RS700 after the adsorption for 14 h. The best PS activation performance was achieved for nZVI/RS500, with MCB removal efficiency being further increased to 98.8% after the oxidation for 3 h and reaction stoichiometric efficiency (RSE) reaching a maximum of 4.1% under conditions of 0.2 g·L −1 nZVI/RS500, 50.0 μM MCB, 2.0 mM PS and pH 0 6.5. The pre-adsorption of MCB was a rate-promoting step in the oxidative degradation processes within the nZVI/RS-PS systems under low RS pyrolysis temperatures (<500 °C). However, excessive adsorptive capacity of nZVI/RS600 and nZVI/RS700 induced blocking of the active sites and low PS activation efficiencies. In addition to transformation of nZVI and surface functional groups on RS500, electron transfer from sp 2 hybridized carbon enhanced by internal electron migration of sp 3 - sp 2 hybridized carbon was also responsible for PS activation, producing SO 4 •− , · OH and 1 O 2 for MCB degradation through both radical and nonradical pathways. Six degradation intermediates were identified with possible degradation pathways of MCB in the nZVI/RS500-PS system being proposed. Additionally, 80.2% and 67.4% of MCB removal rates were achieved in tap water and groundwater contaminated by MCB respectively. These findings have significant implications for the synthesis and application of metal-carbon composite based multifunctional materials with strong adsorption and catalytic potential for activating PS to completely remove organic contaminants in groundwater.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2018
·
IF 2.196
Kai Fan,Feng Zhou,Changxu Chen,Ye Li,Weisong Li,Bo Xiao,Chunjian Xu
Isobaric vapor–liquid equilibria of tert-butanol + chlorobenzene and tert-butyl acetate + chlorobenzene binary systems and the tert-butanol + tert-butyl acetate + chlorobenzene ternary system at 101.33 kPa were measured using a circulation VLE still. The data of binary systems passed the thermodynamic consistency test of the Herington method and the Van Ness point test, and the experimental data of the ternary system also passed the Wisniak consistency test. These binary systems’ VLE data were fitted by the Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models with minor deviations. Furthermore, the obtained binary interaction parameters from the binary systems were used to predict the VLE behavior of the tert-butanol + tert-butyl acetate + chlorobenzene ternary system. The rmsd of vapor and the temperature between the experimental and predicted values for the ternary system were smaller than 0.0304 and 0.81K, respectively. The results indicated that the relative volatility between tert-butanol and tert-butyl acetate obviously increased when adding chlorobenzene as a solvent. Thus, chlorobenzene is a promising solvent for the separation of the tert-butanol and tert-butyl acetate mixture system by extractive distillation.
研究领域:
化学工程
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Sciences
·
2022
·
IF 6.796
Jie Wen,Zewei Liu,Hongxia Xi,Bichun Huang
In this work, hydrothermal technique combined with KOH activation were employed to develop a series of porous carbons (NPCK- x ) using tobacco stem as a low-cost carbon source and (NH 4 ) 2 C 2 O 4 as a novel nitrogen-doping agent. Physicochemical properties of NPCK- x were characterized by Brunauer-Emmett-Teller, field emission scanning electron microscopy, X-ray diffraction, Raman microscope, elemental analysis, and X-ray photoelectron spectroscopy. Results showed that the NPCK- x samples possessed large surface areas (maximum: 2875 m 2 /g), hierarchical porous structures, and high degree of disorder. N-containing functional groups decomposed during activation process, which could be the dominant reason for appearance of abundant mesopores and well-developed pore structure. Dynamic chlorobenzene adsorption experiments demonstrated that carbon materials with (NH 4 ) 2 C 2 O 4 modification exhibited higher adsorption capacity (maximum: 1053 mg/g) than those without modification (maximum: 723 mg/g). The reusability studies of chlorobenzene indicated that the desorption efficiency of (NH 4 ) 2 C 2 O 4 modified porous carbon reached 90.40% after thermal desorption at 100°C under N 2 atmosphere. Thomas model fitting results exhibited that the existence of mesopores accelerated the diffusion rate of chlorobenzene in porous carbon. Moreover, Grand Canonical Monte Carlo simulation was conducted to verify that micropores with pore sizes of 1.2–2 nm of the optimized porous carbon were the best adsorption sites for chlorobenzene and mesopores with pore sizes of 2–5 nm were also highly active sites for chlorobenzene adsorption.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials
·
2024
·Vol. 17
·期 9
·2103
·
IF 3.1
Pengfei Zhu,Qiaosen Yuan,Na Li,Zhaoxia Hu,Shouwen Chen
The development of efficient catalysts with longevity to remove chlorobenzene is challenging due to Cl poisoning. Herein, a series of Mn-Cr/ZrOxcatalysts supported by Zr-based metal-organic framework (UiO-66)-derived ZrOxwas prepared and investigated for chlorobenzene (CB) catalytic oxidation. MnCr/ZrOx-M prepared via a wet impregnation method presented an amorphous structure, indicating the homogeneous dispersion of Cr and Mn, which improved acid and redox properties. 40Mn7Cr3/ZrOx-M exhibited the best catalytic activity for chlorobenzene oxidation with T90of 293 °C, which is mainly due to the strong interaction between manganese and chromium promoted by the large specific surface area of the ZrOxsupport. Furthermore, 40Mn7Cr3/ZrOx-M presented excellent stability for chlorobenzene oxidation.
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
BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY
·
2013
·Vol. 91
·期 5
·522-525
·
IF 1.105
Li Yong-Fang,Yang Zhong-Zhi,Fan Jing,Zhu Yong
Five higher chlorinated benzenes (including hexachlorobenzene (HCB), pentachlorobenzene (PeCB) and three isomers of tetrachlorobenzens) were measured in the livers of grass carp and common carp collected from five markets in Xinxiang city, China. HCB and PeCB were detected in all samples. The major component of the higher CBs residue was HCB and significant correlations existed between HCB and PeCB in both grass carp and common carp livers. The ratio range of HCB/PeCB in grass carp and common carp were 3.4–6.2 and 4.9–7.7, respectively, which implied the sources of higher CBs originate mainly from the revolatilization of industrial HCB with a minor impact from PeCB.
研究领域:
环境科学
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）