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Preparation of nanosized NaA zeolite and its surface modification by KH-550

Hou J., Jiang Q.

Materials Science Poland

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2018

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Vol. 36, No. 4

638--643

EN

Nanosized NaA zeolite was successfully synthesized by hydrothermal method using tetraethyl orthosilicate (TEOS) and aluminum isopropoxide (AIP) as the main raw materials. The surface modification of NaA zeolite was carried out by silane coupling agent 3-aminopropyltriethoxysilane (KH-550). The effects of silane coupling agent dosage, reaction temperature, reaction time, hydrolysis time and pH value on grafting rate of NaA zeolite were investigated in detail. The zeolites were characterized by XRD, SEM-EDS, FT-IR and TG-DTA. The results showed that the surface of NaA zeolite was modified successfully by KH-550. The optimal modification conditions obtained were as follows: the dosage of coupling agent in 95 % ethanol – 1.6 %, reaction temperature − 70 °C, reaction time – 2 h, hydrolysis time – 20 min, and pH value – 3.5. Under these conditions, the grafting rate of modified NaA zeolite was 3.95 %.

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Behavior and mechanism of collophane and dolomite separation using alkyl hydroxamic acid as a flotation collector

Yu J., Ge Y., Hou J.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

155--169

EN

Flotation response of collophane and dolomite using alkyl hydroxamic acid (AH) (chelating collector) was investigated in the paper. The experiments were performed using pure and artificially mixed minerals as well as a real phosphate ore. Their separation mechanisms were studied by means of zeta potential measurements, infrared analysis, adsorption measurements, thermodynamics, and quantum chemical calculations. The results indicated that AH exhibited an excellent performance in the flotation separation of collophane from dolomite in neutral medium. The P2O5 grade of the concentrate increased from 19.84% to 30.51% without any other reagents when the pH value was about 7. The zeta potential and adsorption studies showed that the adsorption of AH at the cellophane/aqueous interface was greater than that at dolomite surface, which was the essential reason that separation of collophane from dolomite. The results of Fourier Transform Infrared (FTIR) spectrum and thermodynamics calculation indicated that the adsorption of AH at collophane was attributed to the chemical bonding. Moreover, AH molecule formed O-O five-membered ring with calcium ion on the collophane surface.

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Preparation, structure and optical properties of transparent conducting gallium-doped zinc oxide thin films

Gu J. H., Lu Z., Long L., Zhong Z. Y., Yang C. Y., Hou J.

Materials Science Poland

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2015

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Vol. 33, No. 3

470--481

EN

Highly conductive gallium-doped zinc oxide (GZO) transparent thin films were deposited on glass substrates by RF magnetron sputtering. The deposited films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), four-point probe and UV-Vis spectrophotometer, respectively. The effect of growth temperature on the structure and optoelectrical properties of the films was investigated. The results demonstrate that high quality GZO films oriented with their crystallographic c-axis perpendicular to the substrates are obtained. The structure and optoelectrical properties of the films are highly dependent on the growth temperature. It is found that with increasing growth temperature, the average visible transmittance of the deposited films is enhanced and the residual stress in the thin films is obviously relaxed. The GZO films deposited at the growth temperature of 400 degrees C, which have the largest grain size (74.3 nm), the lowest electrical resistivity (1.31 x 10(-3) Omega.cm) and the maximum figure of merit (1.46 x 10(-2) Omega(-1)), exhibit the best optoelectrical properties. Furthermore, the optical properties of the deposited films were determined by the optical characterization methods and the optical energy-gaps were evaluated by extrapolation method. A blue shift of the optical energy gap is observed with an increase in the growth temperature.

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Identification and simultaneous determination of glycyrrhizin, formononetin, glycyrrhetinic acid, liquiritin, isoliquiritigenin, and licochalcone A in licorice by LC-MS/MS

Xie J., Zhang Y., Wang W., Hou J.

Acta Chromatographica

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2014

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Vol. 26, no. 3

507--516

EN

A new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of glycyrrhizin, formononetin, glycyrrhetinic acid, liquiritin, isoliquiritigenin, and licochalcone A in licorice. An Eclipse Plus C18 column (I.D. 4.6 × 100 mm, 3.5 μm particle size; Agilent) was used in the analysis. Electrospray ionization (ESI)-tandem interface in the negative mode was performed, and multiple reaction monitoring (MRM) was employed with the precursor multiple reaction monitoring production combination for the determination of six analytes. The average recoveries ranged from 98.30% to 100.13% with relative standard deviations (RSDs) ≤ 1.95%, and limits of detection (LODs) ranged from 2.1 to 3.6 pg. The applicability of this analytical approach was confirmed by the successful analysis of six samples. The results indicated that the established method was validated, sensitive, and reliable for the determination of six analytes in licorice.