MICROCHEMICAL JOURNAL
·
2019
·
IF 3.206
Tao Liu,Xiaoxue Yuan,Gang Zhang,Jing Hu,Jing An,Tong Chen,Gongying Wang
In this study, a fast and sensitive method based on stir bar sorptive extraction (SBSE) and two-step thermal desorption coupled with online gas chromatography-mass spectrometry was established to simultaneously analyse six trace byproducts [phenyl salicylate (PS), xanthone (XA), methyl o -hydroxybenzoate (MS), 2-methyl diphenyl carbonate (PTC), methyl o -methoxybenzoate (MSME) and phenyl o -methoxybenzoate (PSME)] generated in the process of diphenyl carbonate (DPC) synthesis. Analytes were enriched with multiple sorptive stir bars simultaneously, followed by thermal desorption, cryo-focusing, and instantaneous injection, effectively solving such problems as long adsorption time and small sample volumes compared with conventional stir bars. The main factors influencing SBSE and thermal desorption were studied. Optimized stir bar extraction conditions are as follows: the volume fraction of methanol is 10%, the extraction time is 6 min, and the stirring rate is 1200 rpm at room temperature (25 °C). Optimized two-step thermal desorption conditions are as follows: in the first desorption step, the desorption temperature is 300 °C, the desorption time is 10 min, and the valve and transmission line temperature is 200 °C; in the second desorption step, the cold trap temperature is −10 °C, which is increased at a rate of 100 °C/s to 320 °C and held for 5 min. A splitless mode and a split mode with a split ratio of 20:1 are used in the first and the second desorption step, respectively. Under the optimal conditions, the six byproducts generated in the synthesis of DPC via transesterification were quantitatively analyzed by external standard method. The results showed that, within the range of 1.0−100 ng/L for all of the six transesterification byproducts, this method revealed good linearity with correlation coefficients (r) ≥0.997. The limits of detection (LODs) were between 0.054 ng/L and 0.253 ng/L, the relative standard deviations (RSD) were from 5.2% to 11.5%, and the recoveries were 81.6%−102.6% ( n = 3). The method is simple, rapid and has a wide linear range, high accuracy, and sensitivity, as well as good stability. It is suitable for simultaneous, rapid and selective analysis of six trace byproducts in the process of DPC synthesis. It can also provide vigorous data support and industrialization guidance for the selection of transesterification conditions and research on the formation mechanisms, distribution regularity, and even control of transesterification byproducts.
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2019
·
IF 5.128
Tinghao Jia,Si Gong,Lun Pan,Chuan Deng,Ji-Jun Zou,Xiangwen Zhang
Thermal oxidative stability is a key issue for jet fuel serving as a coolant of high-performance aircraft. This study investigated the effects of the hydrogenation degree on the oxidation and deposition of jet fuel (RP-3). Fuels with different hydrogenation degrees were achieved by a commercial catalyst, with the aromatic content reduced from 12.6 wt% to 0.4 wt%, resulting in a slight density decrease and a slight increase of the net heating value. Meanwhile, the total sulfur content of hydrogenated fuel was lowered to below 1 ppm, and the naturally occurring phenols were completely removed. The initial oxidation reactivity and deposition tendency of hydrogenated fuels were investigated by pressure differential scanning calorimetry and jet fuel thermal oxidation tester, respectively. For the initial oxidation, both the oxidation OT (onset temperature) and IP (induction period) of jet fuel decrease with increasing hydrogenation degree and show good linear correlations with the aromatic content. For thermal deposition, pristine RP-3 cannot pass the JFTOT test (355 °C for 5 h), while all hydrogenated RP-3- t can pass 355 °C JFTOT test, owing to the almost total removal of inherent heteroatomic species (sulfurs and phenols) by hydrogenation. This work confirms that deep hydrogenation is a promising approach to improve the thermal oxidative stability of jet fuel (fewer deposits) for the practical applications.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2019
·
IF 3.571
Zhuolin Wang,Qing Xiao,Jinda Zhuang,Tao Feng,Chi-Tang Ho,Shiqing Song
Gas chromatography–olfactometry coupled with sensory analysis and partial least-squares regression (PLSR) analysis led to the identification of the odorants responsible for the different flavors of four yeast extracts. Sensory analysis showed that LA00L had an intense sulfurous attribute, and LA00 was characterized by fatty and green notes, FA31 exhibited the floral odor, while KA02 had strong phenolic, animal, fermented, roasted, and caramellic notes. A total of 37 key aroma compounds with odor activity values greater than 1 were determined. 2,4-Di-tert-butylphenol and methional were the most potent aroma compounds. In addition, the key aroma compounds in LA00L were nonanal, dimethyl disulfide, and γ-decalactone. Octanal, dimethyl disulfide, and benzeneacetaldehyde were the key aroma compounds in LA00. In FA31, styrene, benzeneacetaldehyde, and acetophenone were the key aroma compounds, while indole, 2-methoxyphenol, benzeneacetaldehyde, and p-cresol contributed significantly to the aroma of KA02. PLSR showed that p-cresol and indole were significantly responsible for the phenolic and animal notes inducing the off-flavor (yeasty odor) of yeasty extracts. More significantly, indole was first reported to have an important effect on yeasty odor.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2019
·
IF 6.361
Bo Song,Qiao Wang,Li Wang,Jing Lin,Xin Wei,Vignesh Murugadoss,Shide Wu,Zhanhu Guo,Tao Ding,Suying Wei
Decorating electron-accepting materials on carbon nitride (C 3 N 4 ) is a promising strategy to construct heterostructure catalysts for improved photocatalytic abilities. In this study, B-doped carbon-dots (B-C-dots) decorated C 3 N 4 (C 3 N 4 /B-C-dots) catalysts were fabricated through the surface deposition. The benefits from integration of B-C-dots and C 3 N 4 are four folds: (i) increasing surface area; (ii) improving visible light absorption; (iii) promoting the transfer of photoinduced carriers; and (iv) reducing the recombination of photoinduced carriers. The optimum photocatalytic activity of B-C-dots/C 3 N 4 for Rhodamine B (Rh B) (or tetracycline hydrochloride (TC)) degradation was about 7.21 (6.56) and 4.80 (4.35) times higher than that of C 3 N 4 and C-dots/C 3 N 4 , respectively, exhibiting both remarkable stability and repeatability. Moreover, enhanced photocatalytic activity of C 3 N 4 /B-C-dots could also be attributed to the type-II heterojunction formed between C 3 N 4 and B-C-dots caused by B doping.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Lili Jiang,Qi Wang,Minghua Zhou,Liang Liang,Kerui Li,Weilu Yang,Xiaoye Lu,Ying Zhang
A porous carbon aerogel (CA) was prepared to activate persulfate (PS) for the removal of phenol. The adsorption of phenol on CA and its removal in CA/PS system was fitted to a second-order model and first-order kinetic model, respectively. Influencing factors of CA/PS such as pH, CA dose, PS concentration, phenol concentration and temperature were investigated. CA/PS presented good performance on phenol removal over a pH range of 3–11 with the highest removal obtained at pH 7. Four kinds of organic pollutants including tetracycline , Rhodamine B, Safranine T and malachite green were investigated in the CA/PS system, proving that the adsorption of the contaminants benefitted their subsequent oxidation removal. The removal of aromatic compounds (phenol, p -diphenol, p -chlorophenol, and p -nitrophenol) in CA/PS system followed a decreasing order of hydroxyl > chlorine > nitro. The radical scavenging experiments suggested the removal of phenol was mainly through a non-radical pathway. The study presented the preparation and application of a green catalyst to activate PS, which is very promising for the development of the technology and the treatment of phenolic wastewater.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Peng Zhou,Jing Zhang,Zhaokun Xiong,Yang Liu,Xiaowei Huo,Xin Cheng,Wenshu Li,Feng Cheng,Yongli Zhang
Hydroxylated C 60 Fullerene (Fullerol) induced photochemical production of reactive oxygen species (ROS, e.g. singlet oxygen ( 1 O 2 ) and hydroxyl radical ( OH)) is a slow process, and the role of its surface groups other than high water-solubility is still lack of investigation. In this study, we demonstrate Fullerol can promote Fe(III)/Fe(II) cycles to degrade dimethyl phthalate (DMP) in Fe(III)/H 2 O 2 Fenton system as both an electron donor and an electron-transfer mediator. At acidic condition, the formation of carbonyl and carboxyl via pinacol rearrangement and subsequent keto-enol isomerization can produce cage-opened structure of Fullerol, resulting in the pH-dependent formation of Fe(III)-Fullerol complex. Two pathways of Fe(II) recovery via intramolecular electron transfer of Fe(III)-Fullerol complex to enhance Fe(III)/H 2 O 2 Fenton oxidation were proposed: 1) Fullerol direct reduces Fe(III) into Fe(II) as an electron donor in dark, and it was strongly enhanced under visible light irradiation; 2) Fullerol mediates electron transfer from electron donor (e.g. hydrogen peroxide and organics) to Fe(III) in visible light condition. Furthermore, DMP degradation pathway was proposed based on variation of main intermediates.
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL LETTERS
·
2020
·
IF 1.467
Pan Guo,Song Zheng,Yong Wang,Qianfen Zhuang,Yongnian Ni
Fluorescent tremella-like carbon nanosheets (TCNs) were hydrothermally synthesized using citric acid and adenosine as the starting materials. The resulting product had high quantum yield, water-solubility, and photostability. The addition of 2,4,6-trinitrophenol (TNP) induces remarkable fluorescence quenching, and this phenomenon was used to construct a TNP fluorescence sensor. The fluorescence quenching of TCNs by TNP was shown to be likely due to the inner filter effect. The developed sensor has a wide linear range from 0.05 to 50.0 μM with a detection limit of 5 nM. The TCN-based sensor was used for the determination of TNP in lake water with satisfactory recoveries from 98% to 103%.
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2019
·Vol. 6
·期 11
·115540
·
IF 1.449
Yong Liu,Qiong Luo,Hao Lu,Zhao Wang
The factors influencing the hydrothermal synthesis of ZSM-5 have been investigated in detail, such as silicon source, template, pH, reaction temperature, etc The type of template plays a key role. It is difficult to synthesize ZSM-5 without template or using inorganic template under our research conditions. However, the organic template of tetrapropylammonium bromide (TPABr) or n-butylamine (BTA) is beneficial to the synthesis of HZSM-5. The pH range of 10.79–11.14 is favorable for the synthesis of HZSM-5 zeolite. When temperature is greater than or equal to 160 °C, the synthesis of target zeolites is easy. However, if temperature is ≤140 °C, the synthesized product belongs to amorphous solid. Scanning electron microscopy (SEM) shows that the morphology of HZSM-5 crystal is hexagonal columnar. Fourier transform infrared (FTIR) analysis shows the synthesized product has a good ZSM-5 skeleton structure. The synthetic HZSM-5 zeolite has the BET specific surface area of about 387.326 m2 g−1. The adsorption capacities of the synthesized HZSM-5 for phenol, quinoline and indole can reach up to 43.54 mg g−1, 83.10 mg g−1 and 69.51 mg g−1, respectively.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2019
·Vol. 43
·期 5
·987-995
·
IF 2.516
Jinyi Wu,Lei Tan,Yuling Li,Xiaotong Wu,Yong Liang
Selective removal of bisphenol A from wastewater is quite challenging primarily because of its low concentration and matrix complexity. To this end, according to the molecular structure of bisphenol A, we designed a functional monomer for the preparation of molecularly imprinted mesoporous silica using click chemistry reaction. The resultant bisphenol A imprinted mesoporous silica was characterized by transmission electron microscopy, small angle X-ray diffraction, and N 2 adsorption–desorption experiments. The results indicated that the bisphenol A imprinted mesoporous silica possessed a highly ordered periodic hexagonal mesostructure with the Brunauer–Emmett–Teller surface area of 944.28 m 2 /g. The bisphenol A imprinted mesoporous silica showed fast adsorption kinetics and the saturated adsorption capacity reached up to 88.6 mg/g at pH 6.5, and with relative selectivity factors ranged from 1.06 to 3.20. The adsorption efficiency of the bisphenol A imprinted mesoporous silica was above 97.96% after five extraction/elution cycles. The bisphenol A imprinted mesoporous silica was further applied to the selective removal of bisphenol A from real wastewater samples and showed great promise in practical applications.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 27
·期 4
·4520-4527
·
IF 2.914
Guo Feng,Zhu Zihan,Zheng Zhangqin,Jin Ying,Di Xiaoxuan,Xu Zhonghao,Guan Hongwei
Rampant use of tetracycline in animal feed is a threat to food security, the environment, and human health because of the risk of drug residues. Therefore, it is necessary to establish a sensitive, efficient, and reliable method for qualitative and quantitative detection of tetracycline. In this paper, we synthesized fluorescent carbon dots (FCDs) by thermal cracking of crab shell waste, and obtained a fluorescence quantum yield of 30%. Characterization of the FCDs by transmission electron microscopy, Fourier-transform infrared spectroscopy, ultraviolet visible absorption spectroscopy, and photoluminescence spectroscopy showed that they were fluorescent and evenly distributed with an average size of approximately 10 nm. We designed a sensitive probe for detecting tetracycline using the fluorescence intensity change of the FCDs. This method is sensitive, inexpensive, and environmentally friendly. The concentration of tetracycline was examined by comparing the fluorescence intensities of the FCDs before and after tetracycline addition. The limit of detection for tetracycline was 0.005 mg/L (signal-to-noise ratio = 3), which is promising for method development.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nature Communications
·
2019
·Vol. 10
·期 1
·1-8
·
IF 11.878
Wang Mengfan,Liu Sisi,Qian Tao,Liu Jie,Zhou Jinqiu,Ji Haoqing,Xiong Jie,Zhong Jun,Yan Chenglin
Ambient electrochemical N 2 reduction is emerging as a highly promising alternative to the Haber–Bosch process but is typically hampered by a high reaction barrier and competing hydrogen evolution, leading to an extremely low Faradaic efficiency. Here, we demonstrate that under ambient conditions, a single-atom catalyst, iron on nitrogen-doped carbon, could positively shift the ammonia synthesis process to an onset potential of 0.193 V, enabling a dramatically enhanced Faradaic efficiency of 56.55%. The only doublet coupling representing 15 NH 4 + in an isotopic labeling experiment confirms reliable NH 3 production data. Molecular dynamics simulations suggest efficient N 2 access to the single-atom iron with only a small energy barrier, which benefits preferential N 2 adsorption instead of H adsorption via a strong exothermic process, as further confirmed by first-principle calculations. The released energy helps promote the following process and the reaction bottleneck, which is widely considered to be the first hydrogenation step, is successfully overcome.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials Today Communications
·
2019
·
IF 1.859
Peng Yang,Mengyuan Ren,Kongfa Chen,Yu Liang,Qiu-Feng Lü,Teng Zhang
A novel high-performance epoxy resin diphenyldi (9,9-Di-(4-(2,3-epoxypropoxy) phenyl)-4,5-diazafluorenoxysilane) (DEPFS) containing the diazafluorene and silicon group was synthesized by the nucleophilic substitution for the first time and added to bisphenol A epoxy resin (E-51) to form a thermoset blend. We observed that the incorporation of DEPFS remarkably enhanced the flame retardancy and thermal properties of E-51. The cured E-51-30% DEPFS thermoset exhibited a glass transition temperature of 187 °C and a limiting oxygen index of 30.1%, much higher than 153 °C and 22.6% for those of pristine E-51 thermoset, respectively. In addition, the incorporation of DEPFS has dual enhancement effects on the toughness and tensile strength of E-51. This study provides an effective means to prepare a high-performance epoxy resins and proposes flame retardancy and simultaneous reinforcing and toughening mechanism. It was found that the DEPFS with diverse performance has allowed an increasing number of versatile industrial application such as microelectronics, electronics, aerospace and so on.
✓ 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）