JOURNAL OF SEPARATION SCIENCE
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2016
·Vol. 39
·期 12
·2356-2364
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IF 2.741
Fuyou Du,Qun Qin,Jianchao Deng,Guihua Ruan,Xianqing Yang,Laihao Li,Jianping Li
In this work, a magnetic metal–organic framework designated as MIL-100(Fe) was prepared and applied as a magnetic solid-phase extraction sorbent for the determination of trace polycyclic aromatic hydrocarbons in environmental water samples by coupling with high-performance liquid chromatography and fluorescence detection. The magnetic microspheres exhibited large surface areas and high extraction ability, making them excellent candidates as sorbents for enrichment of trace polycyclic aromatic hydrocarbons. Under the optimized experimental conditions, good sensitivity levels were achieved with low detection limits ranging from 32 to 2110 pg/mL and good linearities with correlation coefficients higher than 0.9990 for the investigated 13 polycyclic aromatic hydrocarbons. The proposed method has been validated in the analysis of real water samples with mean recoveries in the range of 81.4–126.9% at four spiked levels and the relative standard deviations in the range of 1.3–17.0%. The magnetic MIL-100(Fe) microspheres were stable enough for 150 extractions without a significant loss of extraction performance.
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JOURNAL OF CHROMATOGRAPHY A
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2016
·
IF 3.926
Shuqin Liu,Qingkun Hu,Juan Zheng,Lijun Xie,Songbo Wei,Ruifen Jiang,Fang Zhu,Yuan Liu,Gangfeng Ouyang
A series of knitting aromatic polymers (KAPs) were successfully synthesized using a simple one-step Friedel-Crafts alkylation of aromatic monomers and were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Then, as-synthesized KAPs with large surface areas, unique pore structures and high thermal stability were prepared as solid-phase microextraction (SPME) coatings that exhibited good extraction abilities for a series of benzene compounds (i.e., benzene, toluene, ethylbenzene and m -xylene, which are referred to as BTEX) and polycyclic aromatic hydrocarbons (PAHs). Under the optimized conditions, the methodologies established for the determination of BTEX and PAHs using the KAPs-triPB and KAPs-B coatings, respectively, possessed wide linear ranges, low limits of detection (LODs, 0.10–1.13 ng L −1 for BTEX and 0.05–0.49 ng L −1 for PAHs) and good reproducibility. Finally, the proposed methods were successfully applied to the determination of BTEX and PAHs in environmental water samples, and satisfactory recoveries (93.6–124.2% for BTEX and 77.2–113.3% for PAHs) were achieved. This study provides a benchmark for exploiting novel microporous organic polymers (MOPs) for SPME applications.
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Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 34
·18071-18080
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IF 8.867
Zhigao Zhu,Chenghan Ji,Lingling Zhong,Shuang Liu,Fuyi Cui,Hongliang Sun,Wei Wang
Porous carbonaceous materials are widely used as catalyst carriers to activate peroxymonosulfate (PMS) for catalytic oxidative degradation of organic pollutants. Herein, hierarchical structured ferro-cobalt alloyed crystals supported on nitrogen doped activated porous carbon fibers (FeCo2@APCFs) were prepared by a combination of multicomponent electrospinning, activation, and carbonization. Benefiting from the precursor design and activation process, the carbon fibers derived from a PAN/PBZ (polyacrylonitrile/polybenzoxazine) precursor exhibited a tunable porous structure with an ultrahigh specific surface area (SSA) and pore volume of 2085 m2 g−1 and 1.12 cm3 g−1, respectively. Most importantly, the FeCo2 crystals can be directly synthesized by carbonization at high temperature in a N2 flow with no other reducing gases. The as-prepared FeCo2@APCFs exhibited robust activation of PMS with reactive oxygen radicals (SO4˙−, ˙OH, and 1O2) for ultrafast removal of organic pollutants, as well as good stability and recyclability with high total organic carbon (TOC) removal. The catalyst suspended in aqueous solution after catalysis can be easily separated with an external magnet without tedious separation processes. This study is meaningful for the development of novel catalyst carriers or a fascinating strategy for wastewater treatment.
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ACS Sustainable Chemistry & Engineering
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2017
·
IF 5.951
Lujiang Xu,Qian Yao,Ying Zhang,Yao Fu
Due to the irregular polymeric structure and carbon based inactive property, lignin valorization is very difficult. In this study we proposed a new route for lignin valorization by which aromatic amines can be directly produced from lignin by ex situ catalytic fast pyrolysis with ammonia over zeolite catalysts. Meanwhile, the obtained pyrolytic biochar can be activated to produce high surface area N-doped carbon for electrochemical application. Wheat straw lignin served as feed to optimize the pyrolysis conditions. MCM-41, β-zeolite, HZSM-5, HY, ZnO/HZSM-5, and ZnO/HY were screened, and ZnO/HZSM-5 (2 wt % Zn, Si/Al = 50) showed the optimal reactivity for producing aromatic amines due to the desired pore structure and acidity. Temperature, residence time, and ammonia content in the carrier gas displayed significant effects on the product distribution. The maximum yield of aromatic amines was obtained at moderate temperatures around 600 °C, 0.57 s, and 75% ammonia in the carrier gas. Under the optimized conditions, the total carbon yields of pyrolytic bio-oil and aromatic amines were 9.8% and 5.6%, respectively. The selectivity of aniline in the aromatic amines was up to 87.3%. Moreover, the pyrolysis byproduct, biochar, was further activated by KOH at 800 °C under ammonia atmosphere for producing N-doped carbon with high surface area. The pyrolytic biochar and N-doped carbon were characterized by elemental analysis, SEM, XRD, nitrogen adsorption–desorption, and XPS. Cyclic voltammetry (CV) and galvanostatic charge–discharge were employed to investigate the electrochemical performance of pyrolytic biochar and N-doped carbon. The specific capacitance of N-doped carbon reached about 128.4 F g–1.
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Materials Science & Engineering C-Materials for Biological Applications
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2016
·
IF 3.42
Qian Tang,Zai-yong Li,Yu-bo Wei,Xia Yang,Lan-tao Liu,Cheng-bin Gong,Xue-bing Ma,Michael Hon-wah Lam,Cheuk-fai Chow
A photoresponsive surface molecularly imprinted polymer for uric acid in physiological fluids was fabricated through a facile and effective method using bio-safe and biocompatible ZnO nanorods as a support. The strategy was carried out by introducing double bonds on the surface of the ZnO nanorods with 3-methacryloxypropyltrimethoxysilane. The surface molecularly imprinted polymer on ZnO nanorods was then prepared by surface polymerization using uric acid as template, water-soluble 5-[(4-(methacryloyloxy)phenyl)diazenyl]isophthalic acid as functional monomer, and triethanolamine trimethacryl ester as cross-linker. The surface molecularly imprinted polymer on ZnO nanorods showed good photoresponsive properties, high recognition ability, and fast binding kinetics toward uric acid, with a dissociation constant of 3.22 × 10 − 5 M in aqueous NaH 2 PO 4 buffer at pH = 7.0 and a maximal adsorption capacity of 1.45 μmol g − 1 . Upon alternate irradiation at 365 and 440 nm, the surface molecularly imprinted polymer on ZnO nanorods can quantitatively uptake and release uric acid.
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JOURNAL OF THE CHINESE CHEMICAL SOCIETY
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2017
·Vol. 64
·期 10
·1220-1226
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IF 0.935
Liming Qiang,Hong Li,Xueru Dong,Mingxiu Lv,Kui Lu
Surfactant-like peptides (SLPs) can self-assemble into various nanostructures, which have shown great potential for a variety of biomedical and biotechnological applications. In this work, two SLPs, V 4 Y, and V 4 AGY, were designed and synthesized, both of which had hydrophobic head valines (V) with large side-chain steric hindrance effect and the hydrophilic head tyrosine (Y) with a rigid ring and two negative charges in the basic solution. Fourier transform infrared and circular dichroism studies confirmed their different secondary structures, whereas atomic force microscopy and dynamic light scattering characterized the difference in their morphologies. In solution, they formed different secondary structures. Correspondingly, V 4 Y and V 4 AGY formed noncompact spherical aggregates and a spiral clubbed structure, respectively. In V 4 AGY, the introduction of alanine (A) and glycine (G) increased the molecule's flexibility and increased the distance between the tyrosine and four continuous valines, so as to weaken the synergistic action of electronic repulsion and steric hindrance and strengthen the intermolecular hydrogen bond beneficial to β-sheet formation and the axial growth of the self-assembly. Therefore, the flexibility of the molecule and the side-chain steric effect of the two heads of SLPs are non-negligible in the tuning process of peptide self-assembly, in addition to hydrogen-bonding, hydrophobic, and electrostatic interactions.
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ELECTROPHORESIS
·
2017
·
IF 2.744
Meng Ruan,Qiqin Wang,Huihui Wu,Yuqiang Wang,Hai Han,Zhengjin Jiang
In this study, a novel functional monomer N -[1-( α -naphthyl)ethylaminocarbonyl]-D- tert -leucine-[2-(methacryloyloxy)ethyl] amide (NA-D- tert -Leu-MA) was synthesized, and then employed to prepare polymeric monoliths (240 mm × 100 μm id) functionalized with tert -leucine derivative through a single step thermo-initiated co-polymerization approach or a multi-step post-modification approach. The multi-step approach involves the post-modification of a thiol-containing monolith with NA-D- tert -Leu-MA via “thiol-ene”click reaction. The physicochemical properties of the resulting monoliths were characterized by scanning electron microscopy, energy-dispersive X-ray spectrometry and micro-liquid chromatography. Good column stability, permeability, efficiency and reproducibility were obtained for the optimized monoliths. The poly (NA-D- tert -Leu-MA- co -ethylene dimethacrylate) monolith prepared through the single step co-polymerization approach exhibited satisfactory achiral separation performance for various analytes, including phenols, aniline derivatives and intact proteins, while its enantioseparation ability is rather poor. In contrast to that, the monolith prepared through the multi-step post-modification approach showed much higher enantioselectivity for 7-nitro-2,1,3-benzoxadiazole (NBD)-derivatized amino acids. Three NBD-derivatized amino acids (theanine, proline and norleucine) could be baseline enantioseparated.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2017
·
IF 9.446
Runyuan Ma,Liang Wang,Sai Wang,Chengtao Wang,Feng-Shou Xiao
Photocatalysts for pollutant degradation have been extensively investigated but extremely challenging for practical applications, because the radicals formed on the catalyst surface are pernicious to organisms in the nature. We develop a new concept of eco-friendly photocatalyst to impart shape-selective catalysis for pollutants removal but eco-friendly for organisms. The proof-of-concept design is demonstrated by fixing conventional photocatalysts (e.g. TiO 2 , Pt/TiO 2 ) inside of zeolite crystals to form a pomegranate-like structure, as confirmed by electron microscopy and FTIR spectroscopy. In the photodegradation with chlorophyll molecules and grasses as model of the organisms, the zeolite-fixed photocatalysts give ideal performances for the selective degradation of pollutants but are harmless to the organisms, outperforming the conventional photocatalysts. This unique phenomenon is reasonably attributed to the shape-selectivity of the zeolite sheath with uniform micropores, where the pollutant molecules with sizes less than zeolite micropores could be diffused but bulky organisms are hindered to access to the radicals on the TiO 2 surface.
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ANALYST
·
2016
·Vol. 141
·期 9
·2676-2681
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IF 4.033
Bin Bin Chen,Ze Xi Liu,Hong Yan Zou,Cheng Zhi Huang
The detection of nitroaromatic explosives is of great importance owing to their strong explosive power and harmfulness in terms of the environment, homeland security and public safety. Herein, rare earth-doped carbon dots with multifunctional features were firstly prepared by simply keeping the mixture of terbium(III) nitrate pentahydrate and citric acid at 190 °C for 30 min. The as-prepared terbium doped carbon dots (Tb-CDs), through a rapid and simple direct carbonization route, have a size of about 3 nm, and exhibit excitation wavelength dependent emission of blue fluorescence, are stable, and can be applied for the selective and colorimetric detection of 2,4,6-trinitrophenol (TNP) in the range of 500 nM–100 μM with a limit of detection of 200 nM based on the inner filtering effect (IFE) of the excitation and emission bands of Tb-CDs by TNP and the electron transfer (ET) from Tb-CDs to TNP, giving a precise and highly reproducible result for detecting complex water samples.
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Food Analytical Methods
·
2016
·Vol. 9
·期 9
·2491-2500
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IF 2.167
Fan Yunchang,Hu Guitao,Zhang Tianao,Dong Xing,Zhong Yingying,Li Xiaojing,Miao Juan,Hua Shaofeng
A sensitive electrochemical glucose biosensor based on chitosan (CS)/glucose oxidase (GOx)/catalase (CAT)/CS + carboxylic multi-walled carbon nanotubes (MWCNTs-COOH) + ionic liquid (IL) film modified glassy carbon electrode has been developed and its characteristics were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Hydrogen peroxide (H 2 O 2 ) generated during the enzymatic reaction of GOx with glucose could be decomposed by catalase, resulting in the higher sensitivity. The linear range and detection limit were found to be 0.5–100 and 0.2 μmol L −1 , respectively. The proposed biosensor was successfully applied for the determination of glucose in drink and food samples with the spiked recoveries in the range of 95.5 to 101.5 %.
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RSC Advances
·
2016
·Vol. 6
·期 18
·15192-15200
·
IF 3.289
Huan Yuan,Jie Yu,Suling Feng,Yijun Gong
Nitrogen-doped carbon quantum dots (N-CDs) have become a current focus of chemical research due to their superior photoluminescence (PL) properties and high fluorescence quantum yield (QY). In this paper, we reported a facile, simple and low-cost approach for the synthesis of highly fluorescent and stable N-CDs by hydrothermal treatment of maleic acid and ethylenediamine. The as-prepared N-CDs emitted strong blue fluorescence with an absolute QY of up to 45%, and exhibited pH-independent behavior in a wide pH range from 1 to 13 and good water solubility. In addition, the fluorescence of the N-CDs can be significantly quenched by p-nitrophenol (4-NP) through an electron-transfer-induced dynamic quenching mechanism, leading to 4-NP being sensed optically. The sensor presented a good linearity with 4-NP concentration in the range of 0.10–11 μg mL−1. The detection limit of 22 ng mL−1 4-NP could be obtained, which is lower than the 60 ng mL−1 limit allowed in drinking water by the U. S. Environmental Protection Agency. The sensor exhibited rapid recognition and distinguished selectivity to 4-NP over other structural analogues of phenols. Moreover, the sensing system was successfully applied for the determination of 4-NP in environmental water samples.
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Analytical Methods
·
2016
·Vol. 8
·期 10
·2226-2232
·
IF 1.915
Linye Jiang,Haijian Liu,Ming Li,Yue Xing,Xueqin Ren
We tested a simple and economical approach to synthesize CdTe quantum dots (QDs). We then developed a MIP-capped CdTe QD fluorescent sensor by anchoring a molecularly imprinted polymer (MIP) layer on the surface of CdTe QDs using 3-aminopropyltriethoxysilane as the functional monomer and tetramethoxysilane as the cross-linker via a surface molecular imprinting process. The sensor possessed the sensitivity of CdTe QDs, the selectivity of the molecular imprinting technique, and a nearly spherical morphology. The fluorescence of the MIP-capped CdTe QDs can be efficiently quenched when the template 4-nitrophenol (4-NP) rebinds to the binding sites, as a result of the charge transfer from QDs (donor) to 4-NP (acceptor). MIP-capped CdTe QDs generated a significantly reduced fluorescence intensity within the initial 12 min of binding 4-NP. Under optimized conditions, the sensor presented a satisfactory linearity with 4-NP concentrations in the range of 1–30 μM, and the detection limit was 40 nM. The sensor also successfully detected trace amounts of 4-NP in water samples, and the recovery of 4-NP in three spiked samples ranged from 95.1% to 98.1% with relative standard deviations below 4.3%. The results provide an alternative method for the development of sensors for the rapid recognition and determination of 4-NP in water samples.
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