Ultrasonic-assisted Dispersion Research Articles

超声波辅助分散法制备镨掺杂钛酸钙荧光效果珠光颜料

CaTiO3∶Pr3+ based pearlescent pigments with fluorescent were prepared by ultrasonicassisted dispersion technique. The samples were characterized by fluorospectro-photometer,laser particle size analyzer,X-ray diffraction,scanning electron microscopy and automatic colorimeter, respectively. The results show that the sample obtained from TiO 2-mica pearlescent pigments with CaO coating ratio 5. 3% and calcinating at 900 ℃ for 150 min gives a narrow particle size distribution( the average diameter is 24. 34 μm) with a homogeneous,dense and smooth surface. It gives white color under the solar light. The characteristic color( L*,a*,b*) of the sample is( 89. 03,- 1. 29,1. 00). The maximum emission wavelength is a red light of 613 nm under the excitation of ultraviolet at 304 nm,corresponding to the transition for1D 2 →3H 4. The average fluorescent lifetime is 154. 50 μs.

Ultrasonic-Assisted Dispersive Liquid Phase Microextration with Low-Volume Toxic Solvent for the Separation of Strontium and its Application for Strontium Isotope Determination

In this paper, a new and novel method of ultrasonic-assisted dispersive liquid phase microextration was applied for the pre-concentration of trace strontium ion in water samples, which was determined by inductively coupled plasma optical emission spectroscopy. In this pretreatment, acetonitrile was used as dispersive solvent, 1,1,2,2-tetrachloroethane as an extractant and dicyclohexyl-18-crown-6 as the chelating reagent. The factors influencing the extraction of the method were optimized. These factors were type and volume of extraction solvents, the type and volume of dispersive solvents, pH value and extraction time. The linear ranged from 40 to 2000 mu g/L with the limit of detection of 12 mu g/L. Under the optimum condition, the amount of strontium and the variation of strontium isotopic composition in four real water samples were investigated by the proposed method. The method can be applied to the determination of strontium and its isotopic composition in environmental samples.

The study on the source of Te and the dispersion of TeO 2 in fabricating Mo–V–Te and Mo–V–Te–Nb mixed metal oxide catalysts for propane partial oxidation

The effects of the source of Te and the dispersion of TeO 2 on fabricating Mo–V–Te and Mo–V–Te–Nb mixed metal oxide (MMO) catalysts for propane partial oxidation to acrylic acid (AA) were systematically studied. In order to modify the dispersion of TeO 2 in the preparation medium, wet-milling and ultrasonic-assisted dispersion of TeO 2 were adopted. The selected samples were characterized by means of BET, XRD, ICP/XRF, XPS, SEM, H 2- and C 3H 8-TPR and calorimetric NH 3 adsorption. It was clearly demonstrated that different sources of Te and dispersion of TeO 2 in preparation showed significant impact on the physicochemical properties (phase composition, bulk/surface elemental concentration, reactivity of lattice oxygen, and surface acidity) and catalytic activity of the MMO catalysts. The employment of ultrasonic treatment was proved to be effective for making more active and selective Mo–V–Te/Mo–V–Te–Nb catalysts for the target action.