CATALYSIS LETTERS
·
2012
·Vol. 143
·期 2
·200-205
·
IF 2.242
Zeng Yan,Wang Yanhua,Xu Yicheng,Song Ying,Jiang Jingyang,Jin Zilin
Abstract A thermoregulated ionic liquid and organic biphasic system composed of ionic liquid [CH 3 (OCH 2 CH 2 ) 16 N + Et 3 ][CH 3 SO 3
− ] (IL PEG750 ) with IL PEG750 -stabilized Pd nanoparticles and organic solvents, which allows for not only a highly efficient homogeneous catalytic reaction, but also an easy biphasic separation and reuse of catalyst attributed to the thermoregulated phase-transition property of the system, was employed for Heck reaction. The IL PEG750 -stabilized Pd nanoparticle catalyst exhibited high efficiency, more importantly, after reaction the Pd nanoparticle catalyst could be separated from products by simple phase separation and recycled for six times without evident loss of activity. Graphical Abstract A thermoregulated ionic liquid and organic biphasic system containing [CH 3 (OCH 2 CH 2 ) 16 N + Et 3 ][CH 3 SO
- 3
] (IL PEG750 )-stabilized Pd nanoparticles was applied to Heck reaction for the first time. The Pd nanoparticle catalyst exhibited high efficiency and good recyclability.
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Nano Research
·
2015
·Vol. 8
·期 12
·3853-3863
·
IF 7.01
Zhang Juan,Lv Jun,Wang Xiaonan,Li Defeng,Wang Zhaoxia,Li Genxi
Here we developed a saccharic colorimetric method based on the combination of chemoselective ligation and enzyme-specific catalysis using aminooxy/hydrazine-functionalized gold nanoparticles (AO/AuNPs or H/AuNPs). In the detection of galactose (Gal), galactohexodialdose (GHDA), the galactose oxidase (GalOx)-catalyzed product, has an aldehyde group, which allows it to chemoselectively react with an aminooxy or hydrazine group at the outer layer of AO/AuNPs or H/AuNPs by oxime/hydrazone click chemistry to form oxime or hydrozone. Consequently, through the specific recognition of 1,4-phenylenediboronic acid (PDBA) on cis-diols, GHDA, which contains two pairs of hydroxyls in the cis form, can bind not only with AO/AuNPs or H/AuNPs, but also with PDBA to form boronate diester, thereby triggering the aggregation of AuNPs and causing the corresponding color change. As GalOx catalyzed specific substrates, the amount of Gal correlated with the production of GHDA and the extent of AuNPs aggregation, thus allowing a simple and easily operatable colorimetric method for Gal detection to be developed. Under the optimized experimental conditions, the ratios of absorbance at a wavelength of 617 nm to that at 536 nm vary linearly with the logarithmic values of Gal concentrations within a wide range of 500 nM to 5 mM. Moreover, this colorimetric method shows anti-interference capability and high sensitivity with a detection limit of 21 nM. Thus, a universal platform for accurate and specific colorimetric analysis can be established through the integration of chemoselective ligation with enzyme specific catalysis.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2015
·Vol. 27
·期 1
·1020-1030
·
IF 1.569
Zhou X. J.,Shi P. H.,Qin Y. F.,Fan J. C.,Min Y. L.,Yao W. F.
Co 3 O 4 /graphene composites were synthesized and their high catalytic activity for the activation of peroxymonosulfate to remove the azo dye (Orange II) in aqueous solutions was found. As for the poor quality of rGO by the chemical process of graphene oxide, here, pristine graphite was exfoliated into graphene flakes through direct sonication with assistance of cetyltrimethyl ammonium bromide, which serves as a dispersant in the solvothermal procedure. The physical and chemical performance of Co 3 O 4 /graphene was characterised by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy and thermogravimetric analysis. The obtained Co 3 O 4 nanocrystals were 15–25 nm in size and connected with each other to form the shape of sticks dispersing on graphene sheets. The Co 3 O 4 /graphene composites completely degraded Orange II solutions within 10 min, the catalyst can be reutilized, and the catalytic activity of the Co 3 O 4 /graphene dropped slightly after four successive runs. In addition, the mechanism for the formation of Co 3 O 4 /graphene nanostructures is also illustrated.
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MICROCHIMICA ACTA
·
2015
·Vol. 182
·期 9
·1791-1796
·
IF 3.741
Li Lu,Lin Zheng-zhong,Chen Xiao-mei,Zhang Hong-yuan,Lin Yi-dong,Lai Zhu-zhi,Huang Zhi-yong
Molecularly imprinted polymer (MIP) particles for malachite green (MG) were prepared by emulsion polymerization using methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, and a combination of Span-80 and Tween-80 as an emulsifier. The MIP particles were characterized by SEM micrographs and FT-IR spectra. Their binding capacity for MG was evaluated based on kinetic and isothermal adsorption experiments and compared to non-imprinted polymer particles. Analytical figures of merit include an adsorption equilibrium time of 15 min, an adsorption capacity of 1.9 mg∙g‾ 1 in acetonitrile-water (20:80), and an imprinting factor of 1.85. The MIP particles were successfully applied to the extraction of MG from fish samples spiked with MG and the other interfering substances prior to its determination of MG by HPLC. Spiked samples gave recoveries of MG that ranged from 86 to 104 %, much higher than that of the other interfering substance.
Molecularly imprinted polymer particles for malachite green (MG) were prepared by emulsion polymerization. They show adsorption capacity of 1.9 mg∙g‾¹ with imprinting factor of 1.85, and were successfully applied to the extraction of MG from spiked fish samples.
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International Journal of Environmental Science and Technology
·
2015
·Vol. 13
·期 1
·113-124
·
IF 2.19
Wang Z.,Ye C.,Wang H.
Amino group exhibits alkaline properties. Amino functionalized imidazole-modified silicas would benefit the adsorption of phenolic compounds. Coupling agent between the silica and the imidazolium ring has an effect on adsorption performance. In this paper, two adsorbents were synthesized for the surface bonding of N -(3-aminopropyl)-imidazole onto silicas modified by 3-chloropropyltriethoxysilane and 3-mercaptopropyltrimethoxysilane, respectively. Infrared spectra, elemental analysis, thermogravimetric analysis and N 2 adsorption–desorption isotherms were used to characterize the two adsorbents, and their adsorption capacities of 2,4-dinitrophenol from aqueous solutions were investigated in detail. The experimental results indicated that amino group plays an important role in the enhancement of adsorption capacities of 2,4-dinitrophenol. The adsorbent with 3-mercaptopropyltrimethoxysilane as coupling agent exhibited lower adsorption capacity due to a weak electron–electron repulsion between the non-bonding electrons of sulfur atom and π electrons of benzene ring of 2,4-dinitrophenol. The adsorption kinetics fitted well with pseudo-second-order model. The two adsorbents could be regenerated and reused eight times at least by washing with HCl. The adsorption mechanism was also discussed.
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Nano Research
·
2015
·Vol. 8
·期 10
·3237-3249
·
IF 7.01
Liang Ruowen,Jing Fenfen,Shen Lijuan,Qin Na,Wu Ling
Proper design and preparation of high-performance and stable dual functional photocatalytic materials remains a significant objective of research. In this work, highly dispersed noble-metal nanoparticles (Au, Pd, Pt) were immobilized on MIL-100(Fe) (denoted M@MIL-100(Fe)) using a facile room-temperature photodeposition technique. The resulting M@MIL-100(Fe) (M = Au, Pd, and Pt) nanocomposites exhibited enhanced photoactivities toward photocatalytic degradation of methyl orange (MO) and reduction of heavy-metal Cr(VI) ions under visible-light irradiation (λ ≥ 420 nm) compared with blank-MIL-100(Fe). Combining these results with photoelectrochemical analyses revealed that noble-metal deposition can effectively improve the charge-separation efficiency of MIL-100(Fe) under visible-light irradiation. This phenomenon in turn leads to the enhancement of visible-light-driven photoactivity of M@MIL-100(Fe) toward photocatalytic redox reactions. In particular, the Pt@MIL-100(Fe) with an average Pt particle size of 2 nm exhibited remarkably enhanced photoactivities compared with those of M@MIL-100(Fe) (M = Au and Pd), which can be attributed to the integrative effect of the enhanced light absorption intensity and more efficient separation of the photogenerated charge carrier. In addition, possible photocatalytic reaction mechanisms are also proposed.
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FOOD SCIENCE AND BIOTECHNOLOGY
·
2015
·Vol. 24
·期 3
·843-850
·
IF 0.653
Zhu Chang-Yue,Wang Xiao-Peng,Zhao Xin-Huai
Transglutaminase at a concentration of 10 kU/kg of protein and degraded chitosan were used for glycosylation and crosslinking of caseinate at a fixed molar ratio of the acyl acceptor to the acyl donor of 3:1, a protein concentration of 50 g/L, a pH 7.5 at 37°C, and a reaction time of 4 h. Electrophoretic and chemical analyses showed glycosylation and crosslinking of caseinate. Glycosylated and crosslinked caseinate (GC-caseinate) contained glucosamine at 12.77 g/kg of protein, and the protein fraction had fewer reactable amino groups than original caseinate (0.58 vs. 0.64 mol/kg of protein). GC-caseinate exhibited an enhanced surface hydrophobicity, in vitro digestibility, water-binding capacity, and rheological properties, with poor protein dispensability and emulsification activity, but a similar oilbinding capacity and emulsion stability, compared with original caseinate. GC-caseinate also exhibited better properties than transglutaminase-crosslinked caseinate. Glycosylation and crosslinking was effective for better water-binding and rheological properties of caseinate.
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Nanoscale Research Letters
·
2014
·Vol. 9
·期 1
·1-9
·
IF 2.481
Zhao Qin,Jamal Ruxangul,Zhang Li,Wang Minchao,Abdiryim Tursun
In this study, a simple one-step template-free solution method was developed for the preparation of poly(3,4-ethylenedioxythiophene) (PEDOTs) with different morphologies by adjusting various ratios of oxidant (FeCl 3 ·6H 2 O) to monomer (3,4-ethylenedioxythiophene (EDOT)). The results from structural analysis showed that the structure of PEDOT was strongly affected by the oxidant/monomer ratio, and the polymerization degree, conjugation length, doping level, and crystallinity of PEDOT decreased with increasing of the oxidant/monomer ratio. The morphological analysis showed that PEDOT prepared from an oxidant/monomer ratio of 3:1 displayed a special coral-like morphology, and the branches of ‘coral’ would adjoin or grow together with increasing content of oxidant in the reaction medium; consequently, the morphology of PEDOT changed from coral to sheets (at an oxidant/monomer ratio of 9:1). The electrochemical analysis proved that the PEDOT prepared from an oxidant/monomer ratio of 3:1 had the lowest resistance and the highest specific capacitances (174 F/g) at a current density of 1 A/g with a capacity retention rate of 74% over 1,500 cycles, which indicated that the PEDOT with a coral-like morphology could be applied as a promising electrode material for supercapacitors.
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MICROCHIMICA ACTA
·
2014
·Vol. 181
·期 9
·1069-1075
·
IF 3.719
Ling Yu,Li Jia Xing,Qu Fei,Li Nian Bing,Luo Hong Qun
We report that the intensity of the blue fluorescence of copper nanoclusters coated with polyethyleneimine (PEI) is strongly reduced in the presence of the food dyestuffs Sudan I-IV. This finding was exploited in a label-free fluorescence assay for these Sudan dyes both in ethanol and aqueous solutions. The PEI-capped nanoclusters have an average diameter of 1.8 nm and are displaying, under 355 nm excitation, a blue emission at 480 nm that matches the absorption bands of the Sudan dyes. The clusters are stable in solution for at least 1 month. Under optimum conditions, this assay can be applied to the quantification of the dyes Sudan I, II, III, and IV, respectively, in the 0.1−30, 0.1–30, 0.1–25, and 0.1–25 μM concentration ranges, and the detection limits (3σ/slope) are 65, 70, 45, and 50 nM, respectively. The capability of reducing the fluorescence of the PEI-capped copper nanoclusters is directly related to the number of the functional groups in that Sudan III and IV give lower detection limits. This analytical scheme exhibits a remarkably high selectivity for the Sudan dyes over potentially interfering substances. The method was successfully applied to determine Sudan I, II, III, and IV in hot chilli powder.
The blue fluorescence emission of copper nanoclusters coated with polyethyleneimine (PEI) is strongly reduced in the presence of Sudan I-IV. This finding was exploited in a label-free fluorescence assay for these Sudan dyes both in ethanol and aqueous solutions.
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Nanoscale Research Letters
·
2014
·Vol. 9
·期 1
·1-8
·
IF 2.481
Abdiryim Tursun,Ali Ahmat,Jamal Ruxangul,Osman Yakupjan,Zhang Yu
Poly(3,4-ethylenedioxythiophene)/zinc oxide (PEDOT/ZnO) nanocomposites were prepared by a simple solid-state heating method, in which the content of ZnO was varied from 10 to 20 wt%. The structure and morphology of the composites were characterized by Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) absorption spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The photocatalytic activities of the composites were investigated by the degradation of methylene blue (MB) dye in aqueous medium under UV light and natural sunlight irradiation. The FTIR, UV-vis, and XRD results showed that the composites were successfully synthesized, and there was a strong interaction between PEDOT and nano-ZnO. The TEM results suggested that the composites were a mixture of shale-like PEDOT and less aggregated nano-ZnO. The photocatalytic activity results indicated that the incorporation of ZnO nanoparticles in composites can enhance the photocatalytic efficiency of the composites under both UV light and natural sunlight irradiation, and the highest photocatalytic efficiency under UV light (98.7%) and natural sunlight (96.6%) after 5 h occurred in the PEDOT/15wt%ZnO nanocomposite.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2015
·Vol. 23
·期 1
·351-365
·
IF 2.828
Wang Changhui,Jiang He-Long,Xu Huacheng,Yin Hongbin
The use of phosphorus (P) inactivating agents to reduce internal P loading from sediment for lake restoration has attracted increasing attention. Reasonably, the physicochemical properties of P inactivating agents may vary with the interference of various environmental factors, leading to the change of control effectiveness and risks. In this study, the effect of fulvic acid (FA) adsorption on the properties of two agents, drinking water treatment residuals (DWTRs) and Phoslock®, was investigated. The results showed that after adsorption, there was little change for the main structures of DWTRs and Phoslock®, but the thermostability of Phoslock®, as well as the particle size and settleability of the two agents decreased. The specific surface area and pore volume of DWTRs also decreased, while those of Phoslock® increased. Further analysis indicated that aluminum and iron in DWTRs were stable during FA adsorption, but a substantial increase of lanthanum release from Phoslock® was observed, in particular at first ( P < 0.01). Moreover, the P immobilization capability of DWTRs had little change after FA adsorption, while the capability of Phoslock® after FA adsorption decreased in solutions ( P < 0.001) and sediments ( P < 0.1); interestingly, from the view of engineering application, the performance of Phoslock® was not substantially affected. Overall, each P inactivating agent had its own particular responses of the physicochemical properties to environment factors, and detailed investigations on the applicability of each agent were essential before practical application.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2015
·Vol. 407
·期 25
·7681-7690
·
IF 3.436
Hao Yi,Gao Ruixia,Liu Dechun,Tang Yuhai,Guo Zengjun
A novel surface imprinting polymer based on magnetic carbon nanotubes was prepared using dendritic polyethyleneimine as functional monomer to amplify the number of imprinted cavities. The characteristics of resulting polymers were evaluated by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM). Results suggest that magnetic nanoparticles are deposited onto the surface of multiwalled carbon nanotubes and the imprinted shell is coated on the surface of magnetic carbon nanotubes with a thickness of approximately 8 nm. Magnetic imprinted polymers are sensitive to magnetic fields and can be easily separated within 3 s using an external magnet. The adsorption results indicate that the obtained imprinted polymers have fast kinetics, an ultrahigh adsorption capacity of 479.9 mg g −1 , and satisfactory selectivity towards the template molecule. The prepared materials have excellent stability with no obvious deterioration after six adsorption–regeneration cycles. In addition, a method for determination of gallic acid (GA) in pomegranate rind was developed, using a combination of the prepared polymers used as solid-phase extraction (SPE) sorbents and high-performance liquid chromatography (HPLC) for rapid isolation and determination of GA. The limit of detection of the proposed method is 0.001 μg mL −1 , and the intra and inter-day relative standard deviations (RSDs) are lower than 3.8 % and 5.3 %, respectively. The recoveries of GA from pomegranate rind extract are in the range 98.2–103.6 % with RSDs lower than 4.3 %.
Selective and rapid extraction of gallic acid in pomegranate rind
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