ANALYST
·
2015
·Vol. 140
·期 17
·6047-6053
·
IF 4.107
Min Zhong,Yunlong Dai,Limei Fan,Xiaojing Lu,Xianwen Kan
A facile electrochemical sensor for hydroquinone (HQ) and catechol (CC) determination was successfully fabricated by the modification of poly(3-aminophenylboronic acid) (pAPBA) film and multi-walled carbon nanotubes (MWCNTs) on a glassy carbon electrode (pAPBA/MWCNTs/GCE). The prepared sensor was characterized by scanning electron microscope and electrochemical impedance spectroscopy. Under optimal conditions, differential pulse voltammetry was employed to quantify individual HQ and CC within the concentration range of 5.0 × 10−7–4.0 × 10−5 mol L−1 and 7.0 × 10−6–1.0 × 10−4 mol L−1, respectively. Based on the covalent binding between the boronic acid groups of pAPBA film and the cis-diol-containing molecule, a novel substitution-sensing strategy was proposed for the highly sensitive determination of CC. With the addition of CC into HQ solution, covalent interaction between CC and APBA occurred and the HQ was displaced by CC, resulting in a decrease of HQ oxidation peak current and the increase of the CC oxidation peak current. The summation of both current changes (Δ|IHQ| + Δ|ICC|) were combined for CC sensitive detection in a concentration range of 4.0 × 10−8–1.7 × 10−5 mol L−1 with a limit of detection of 4.3 × 10−9 mol L−1. The sensor was successfully applied to the determination of CC in spiked water samples.
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高影响因子
Soft Matter
·
2014
·Vol. 11
·期 7
·1293-1302
·
IF 4.151
Yiyang Kong,Binjie Hu,Kwang-Leong Choy,Xiaoyu Li,Guangdi Chen
Room temperature ionic liquids (RTILs) are non-volatile organic salts, and few of them with low melting point may replace the conventional coalescing agents in waterborne coatings, thus preventing volatile organic compounds (VOCs) emission, caused by coalescing agents. The formation of waterborne coating containing RTILs can be achieved by the encapsulation of RTILs inside latexes via miniemulsion polymerization. Achieving a stable miniemulsion is a crucial step for further polymerization. In this study, 1-octyl-3-methylimidazolium hexafluorophosphate (C8mimPF6) was chosen, and various factors which might affect droplet size and its stability, including surfactant type, surfactant concentration, and C8mimPF6 concentration, were investigated. It was found that the presence of a small amount of C8mimPF6 coupled with the surfactant would offer marked effects on the droplet size reduction and droplet stability. Such effect may reach its maximum from 1 to 5 wt% C8mimPF6. Above the critical concentration, adding more C8mimPF6 to the oil phase may cause a larger initial droplet size as well as weaken the droplet stability. Such observations were consistent with the zeta potential measurements for miniemulsions prepared under similar conditions.
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POLYMER COMPOSITES
·
2014
·Vol. 36
·期 9
·1597-1605
·
IF 1.455
Ruxangul Jamal,Ahmat Ali,Li Zhang,Yakupjan Osman,Adalet Rahman,Tursun Abdiryim
Poly(3′,4′-ethylenedioxy-2,2′:5′,2″-terthiophene)/ZnO(poly(TET)/ZnO) composites with the ratio of poly(TET) and nano-ZnO from 3:1 to 1:3 were synthesized by hand grinding and ball milling methods, respectively. The photocatalytic activities of the composites were examined through the degradation processes of methylene blue (MB) solution under UV light irradiation, and the possible mechanism for the photocatalytic activity enhancement by synergetic effects between nano-ZnO and poly(TET) was proposed. The results showed that the strong interactions between the poly(TET) and nano-ZnO occurred in the case of ball milling method. The results also proved that the crystallinity of ZnO was not disturbed in both of methods, and the nano-ZnO was uniformly distributed in polymer matrix in the case of ball milling method. The comparative studies showed that the addition of the nano-ZnO could enhance the photocatalytic activities of the composites. The highest degradation efficiency (100%) at 3 h under UV light irradiation occurred in the case of poly(TET)/ZnO(1:1) synthesized by ball milling method. Furthermore, the nanocompsosite displayed higher photocatalytic activity than nano-ZnO, which was due to the holes ( h + ) transferring from the valence band of ZnO to the polymer backbone and the adsorption of MB molecules in polymer matrix via π–π conjugation between MB and aromatic regions of the poly(TET). POLYM. COMPOS., 36:1597–1605, 2015. © 2014 Society of Plastics Engineers
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2017
·
IF 3.012
Waqar Uddin,Gang Hu,Lin Hu,Yanyang Hu,Zhaohui Fang,Rooh Ullah,Xuanxuan Sun,Yu Zhang,Jimei Song
A new technique for identification of two aromatic isomers between 2-hydroxy benzoic acid (2-HBA) and 3-hydroxy benzoic acid (3-HBA) was finalized by using their perturbation effects on a Briggs-Rauscher (BR) oscillator, in which a tetraazamacrocyclic Ni complex, [NiL](ClO 4 ) 2 was used as catalyst. The ligand L in the complex is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. By putting two isomers into this BR oscillator, the 2-HBA caused a decrease in potential (amplitudes), an increase in the period of oscillation (∆ T) and a decrease in number of the oscillation cycle (n) while no influences of 3-HBA on the BR oscillation were observed. Hence, these two aromatic isomers of hydroxy benzoic acid (HBA) were identified in the range from 1 × 10 − 5 to 2.2 × 10 − 4 mol L − 1 . Reaction mechanism of BR has been proposed with reference to the NF and FCA models. An explanation of perturbation mechanism for the BR is that, only 2-HBA reacted with IO 2 • to form 1,2-quinone while the 3-HBA didn't.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2016
·
IF 2.567
Shuai Zhou,Xiang Zhou,Wei Jiang,Tianhe Wang,Ning Zhang,Yue Lu,Liuhua Yu,Zuozhu Yin
Robust superhydrophobic and exceptionally thermostable graphene aerogels exhibiting a three-dimensional macro- and mesoporous structure have been synthesized through a (3-mercaptopropyl)trimethoxysilane-assisted two-step route with natural drying. The facile synthetic process not only guarantees their excellent performance but also greatly improves their practical production rate. The prepared graphene aerogels hold excellent superhydrophobicity, for which water contact angle exceeded 160 degrees, even after 20 ethanol washing–drying cycles. Furthermore, the self-assembly functionalized-graphene sheets enhance the thermal stability of the nanocomposites, due to the good dispersion of functionalized-graphene sheets and the strong bonding between graphene sheets and polymer chains within the aerogels. The study implies a novel and practical methodology to efficiently fabricate three-dimensional composite materials with enhanced performances.
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ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Jingjing Lin,Xiaoming Yan,Gaohong He,Wanting Chen,Dongxing Zhen,Tiantian Li,Lin Ma,Xuemei Wu
A new series of thermoplastic interpenetrating polymer network (TIPN) anion exchange membranes (AEMs) based on poly [2,2′- (p-oxydiphenylene) −5, 5′-bibenzimidazole] (OPBI) and poly(1, 2-dimethy-3-allylimidazolium) (PDAIm) (PBI/DAIm TIPN) has been developed. With 1, 2-dimethy-3-allylimidazolium (DAIm) polymerization in presence of OPBI polymer chains, two kinds of uncrosslinked polymer chains, i.e. PDAIm and OPBI interpenetrate with each other to form a physically crosslinking network. Small steric hindrance effect of the DAIm monomer and non-covalent crosslinking interpenetrating polymer chains contribute to better compatibility and chains flexibility in the TIPN compared with the blend and semi-interpenetrating networks, which are evidenced by SEM and SAXS, promote the aggregation of hydrophilic groups and induce connective ionic conductive channels. PBI/DAIm TIPN membranes achieve well-balanced performance between high hydroxide conductivity and dimensional stability because of the dynamically forced compatibility feature of TIPN. Especially, the PBI/DAIm TIPN-65/0.5 membrane exhibits high hydroxide conductivity (96.7 mS cm −1 ) and low swelling ratio (4.4%) at 80 °C. With low overall alkali uptake (2.89%) and IEC (0.63 mmol g −1 ) of functional groups, it exhibits excellent chemical stability in 1 M KOH at 60 °C for 96 h (94.0% retention) and high tensile strength (48.2 MPa) in hydrated state. These observations suggest TIPN structure provides a promising solution to the electrochemical-mechanical balance of AEMs.
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CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Qihang Yi,Lingjun Bu,Zhou Shi,Shiqing Zhou
In this paper, epigallocatechin-3-gallate/Fe 3 O 4 , a novel heterogeneous catalyst to activate peroxymonosulfate for diuron degradation, was synthesized and its structure was well characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared, and X-ray photoelectron spectroscopy. It was found that the hybrid catalyst showed a better catalytic efficiency than both Fe 3 O 4 and epigallocatechin-3-gallate. This was resulted from the high reduction ability of epigallocatechin-3-gallate, which promoted the cycle of Fe(III)/Fe(II) on the surface of catalyst. Besides, batch experimental results showed that the degradation of diuron depended upon the dosage of catalyst and oxidant, initial pH, and co-existed humic acid. Results demonstrated that high catalyst and oxidant dosages, low initial pH and humic acid were favorable for diuron removal. Furthermore, by adding different dosages of methanol and tertiary butanol, two kinds of radicals were detected to be responsible for diuron degradation in this study and sulfate radical made the predominant contribution. At last, mineralization and degradation pathway were also evaluated in this study. Anyway, it was confirmed that the as-prepared catalyst has the potential superiority for contaminants removal from aqueous solution.
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FOOD CHEMISTRY
·
2016
·
IF 4.052
Xiumei Wang,Daoming Li,Man Qu,Rabia Durrani,Bo Yang,Yonghua Wang
Immobilization of lipase MAS1 from marine Streptomyces sp. strain W007 and its application in catalyzing esterification of n-3 polyunsaturated fatty acids (PUFA) with glycerol were investigated. The resin XAD1180 was selected as a suitable support for the immobilization of lipase MAS1, and its absorption ability was 75 mg/g (lipase/resin ratio) with initial buffer pH value of 8.0. The thermal stability of immobilized MAS1 was improved significantly compared with that of the free lipase. Immobilized MAS1 had no regiospecificity in the hydrolysis of triolein. The highest esterification degree (99.31%) and TAG content (92.26%) by immobilized MAS1-catalyzed esterification were achieved under the optimized conditions, which were significantly better than those (82.16% and 47.26%, respectively) by Novozym 435. More than 92% n-3 PUFA was incorporated into TAG that had similar fatty acids composition to the substrate (n-3 PUFA). The immobilized MAS1 exhibited 50% of its initial activity after being used for five cycles.
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高影响因子
ENERGY
·
2017
·
IF 4.52
Zhijun Zhao,Xiao Xing,Zhigang Tang,Yong Zheng,Weiyang Fei,Xiangfeng Liang,E. Ataeivarjovi,Dong Guo
CO 2 capture with solvent-based process is known as a promising technology for controlling the global warming. In this work, the constant-volume method was used to investigate CO 2 solubility in DMC, ionic liquid of [Omim][BF 4 ], and their mixtures from 298.15 to 328.15 K under pressures up to about 3 MPa. The COSMO-RS model was used to predict the Henry's constants and the vapor pressures of DMC in the mixtures. The experimental results showed the CO 2 solubility in [Omim][BF 4 ] is higher than DMC at 318.15–328.15 K and adding [Omim][BF 4 ] into DMC can decrease the viscosity compared to the pure [Omim][BF 4 ]. Besides, the COSMO-RS simulation results showed the Henry's constants in the mixtures increases with the decreasing mass ratio of [Omim][BF 4 ] which are consistent with experimental values and the vapor pressures of DMC in the mixtures decreases with the increasing mass ratio of [Omim][BF 4 ]. Moreover, the activation energy ( Ea ) predicted from viscosity showed the higher viscosity mean the larger Ea and the larger Ea indicate the higher CO 2 solubility in these solvents. Finally, the mixtures of DMC and [Omim][BF 4 ] may be used as promising physical solvents to capture CO 2 with high partial pressures, which combine the advantages of organic solvents and ionic liquids.
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INORGANIC CHEMISTRY
·
2017
·
IF 4.857
Yi-Gang Chen,Nan Yang,Xing-Xing Jiang,Yao Guo,Xian-Ming Zhang
The first lead tellurate–nitrate nonlinear-optical (NLO) crystal, Pb9Te2O13(OH)(NO3)3, featuring a 3D anionic diamondlike toplogical structural motif formulated as [Pb9O13]8– constructed by unique nonanuclear basket-shaped Pb@Pb8O14 clusters has been hydrothermally achieved, in which the Pb@Pb8O14 cluster shows a core–shell structure with one PbO10 polyhedron enclosed by eight PbOx (x = 3 and 4) polyhedera via edge and face sharing. The hexavalent Te in TeO5(OH) octahedra is linked to a [Pb9O13]8– cluster to form a rare [Pb9Te2O13(OH)]3+ cationic framework. The compound demonstrates a powder second-harmonic-generation (SHG) response of about 1.2 times that of KH2PO4 (KDP) as well as a wide transparency range. Calculations on the local dipole moment and SHG coefficient reveal that the net polarization is zero because of a Kleinman-forbidden point group. Further analysis shows that the SHG response results from structure-induced variations by thermal vibrations of the lattice rather than the intrinsic dipole moment, which offers another insight on the design of new NLO materials.
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APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Xiao Shang,Kai-Li Yan,Zi-Zhang Liu,Shan-Shan Lu,Bin Dong,Jing-Qi Chi,Xiao Li,Yan-Ru Liu,Yong-Ming Chai,Chen-Guang Liu
Oxidized carbon fiber (oCF) as support successfully realizes the vertical growth of uniform WS 2 nanosheets arrays for efficient hydrogen evolution reaction (HER) via a facile hydrothermal process. Thanks to oxygen functional groups on oCF, vertical WS 2 nanosheets structures have grown more easily on oCF, which can provide better dispersion, short charge transfer distance and more exposed active sites for HER in comparison with bulk WS 2 and WS 2 nanosheets on bare carbon fiber (CF) fabricated at the same condition. The electrochemical measurements confirmed that WS 2 /oCF possesses better HER activity than bulk WS 2 and WS 2 /CF. Especially, the 10-h stability with unchanged vertical WS 2 nanosheets morphology further demonstrate the positive effect of oxygen functional groups on the enhanced vertical structure and close combination between WS 2 and oCF. It may offer a facile way to realize more exposed active sites from stable electrocatalyst hybrids of transition metal sulfides by surface oxidization of carbon supports.
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JOURNAL OF CHEMICAL THERMODYNAMICS
·
2016
·
IF 2.196
Yaran Yin,Chunying Zhu,Youguang Ma
Densities and viscosities of binary {[Bmim][BF 4 ] + H 2 O}, {[Bmim][BF 4 ] + MEA}, (MEA + H 2 O) and ternary mixtures {[Bmim][BF 4 ] + MEA + H 2 O} were measured at T = (293.15–333.15) K. The volumetric and viscometric properties, such as excess molar volume V E , viscosity deviation Δ η , and excess Gibbs energy of activation of viscous flow Δ G ∗E for all mixtures, and apparent molar volume, excess partial molar volume and Grunberg-Nissan interaction parameter G 12 for binary mixtures, were deduced from experimental results, and the intermolecular interactions in solutions were also analysed. The excess molar volumes were correlated using the Redlich-Kister polynomial equation for binary mixtures, and Singh et al. equation for the ternary mixture with corresponding binary parameters. The viscosities of binary and ternary solutions were respectively fitted by Jouyban-Acree equation and its extended equation at each measurement temperature, the correlated values are in good agreement with the corresponding experimental data.
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