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Vu T.A.,Vietnam Academy of Science and Technology | Le G.H.,Institute of Chemistry VAST | Vu H.T.,Vietnam Academy of Science and Technology | Nguyen K.T.,Institute of Chemistry VAST | And 6 more authors.
Materials Research Express | Year: 2017

An Fe-MIL-88B/graphene oxide (GO) composite was successfully synthesized by the hydrofluoric acid (HF) free-solvothermal method. The sample was characterized by x-ray diffraction (XRD), N2 adsorption-desorption Brunauer Emmett Teller (BET) method, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and x-ray photoelectron spectroscopy (XPS). BET shows that Fe-MIL-88B/GO is of a mesoporous structure, while XRD and XPS results reveal that besides the Fe-MIL-88B phase, a new FeOOH phase in the novel Fe-MIL-88B/GO composite is formed. The as-prepared Fe-MIL-88B/GO nanocomposite was used to test the photocatalytic degradation of reactive dye (reactive red-RR195) from aqueous solution. This novel metal-organic framework (MOF)/GO composite exhibited excellent photocatalytic activity. Thus, after 25 min of reaction under simulated sunlight irradiation, removal efficiency reached 98%. Moreover, this composite still maintained high photocatalytic activity after three cycles of reaction runs, indicating its high stability and reusability. This opens a new application potential for MOF/GO as a highly efficient photo-Fenton catalyst. © 2017 IOP Publishing Ltd.

Morel S.,SONAS EA 921 | Landreau A.,SONAS EA 921 | Landreau A.,Institute of Chemistry VAST | Nguyen V.H.,Institute of Chemistry VAST | And 6 more authors.
Phytochemical Analysis | Year: 2012

Introduction The Derris genus is known to contain flavonoid derivatives, including prenylated flavanones and isoflavonoids such as rotenoids, which are generally associated with significant biological activity. Objective To develop an efficient preparative isolation procedure for bioactive cajaflavanone. Methodology Fast centrifugal partition chromatography (FCPC) was optimised to purify cajaflavanone from Derris ferruginea stems in a single step as compared to fractionation from the cyclohexane extract by successive conventional solid-liquid chromatography procedures. The purification yield, purity, time and solvent consumption per procedure are described. The anti-fungal, anti-bacterial, anti-leishmanial, anti-plasmodial, anti-oxidant activities and the inhibition of advanced glycation end-products (AGEs) by cajaflavanone accumulation are described. Results FCPC enabled cajaflavanone purification in a single separation step, yielding sufficient quantities to perform in vitro biological screening. Interestingly, cajaflavanone had an inhibitory effect on the formation of AGEs, without displaying any in vitro anti-oxidant activity. Conclusion A simple and efficient procedure, in comparison with other preparative methods, for bioactive cajaflavone purification has been developed using FCPC. Copyright © 2011 John Wiley & Sons, Ltd.

An N.T.,Institute of Chemistry VAST | Thien D.T.,Institute of Chemistry VAST | Dong N.T.,Institute of Chemistry VAST | Le Dung P.,Institute of Chemistry VAST | And 3 more authors.
Carbohydrate Polymers | Year: 2011

Water-soluble O-methyl glucomannan derivatives (O-MGs) with various degrees of substitution were obtained by direct alkylation reaction of an insoluble glucomannan with methyl iodide without any organic solvent including methanol and dimethyl sulfoxide. The structure of O-MGs was characterized by 1H, 13C, 1H 13C NMR-HSQC, and 1H 13C NMR-HMBC spectra. The reactive conditions for synthesizing of O-MG derivatives were also evaluated. The results shown that the optimal conditions for methylation of glucomannan were pH 10, temperature of 40 °C for 3 h. The degree of substitution (DS) of O-substitution increased from 0.09 to 0.175 since the ratio (w/v) of glucomannan/methyl iodide changed from 1/3 to 1/15. © 2010 Elsevier Ltd. All rights reserved.

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