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Yinchuan, China

Wang Z.,Soochow University of China | Hong R.,Soochow University of China | Hong R.,Fuzhou University | Hong R.,Nanocom Inc.
Journal of Polymer Research

The monodisperse cross-linked PS-DVB-GMA-amino-Fe3O4 magnetic microspheres with functional group of amino were synthase by seed swelling method using PS microspheres as seeds, and glycidyl acrylate as monomer in the swelling polymerization; and then modified poly (styrene-glycidyl methacrylate) (PS-DVB-GMA) microspheres with ethylene diamine to form amino-groups; subsequently, Fe3O4 nanoparticles were grafted on the microspheres through in situ precipitation reaction. The morphology, composition, magnetic properties, and crystalline structure of the magnetic microspheres were characterized by scanning electron microscope with energy dispersive analysis of X-rays (SEM/EDX), transmission electron microscopy(TEM), vibrating sample magnetometer(VSM), X-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) methods, respectively. The resulting PS-DVB-GMA-amino-Fe3O4 magnetic microspheres were tested for their ability to remove copper (II) ions from an aqueous solution in batch experiments. The effects of adsorption time and pH value on the adsorbed dosage of copper ions on magnetic microspheres was investigated. Besides, two adsorption isotherm models (i.e., the Langmuir and the Freundlich models) were used to fit the experimental isotherm adsorption data. The average size of microspheres was 5.92 μm with the PDI was 0.024. The composite magnetic microspheres could be easily separated from solution by magnetic decantation using a permanent magnet. The adsorption experiments demonstrate that copper ions adsorption onto the PS-DVB-GMA-amino-Fe3O4 magnetic microspheres reaches a maximum after the 45 min. The maximum adsorption capacities (qe = 76.8 mg/g) was reached at the pH value of 5.0 when the temperature was 25 °C, and by simulating the experimental data with the Langmuir, the maximum equilibrium absorption capacity of PS-DVB-GMA-amino-Fe3O4 magnetic microspheres was 134.0216 mg/g, showing a good adsorptive property to Cu (II). © 2015, Springer Science+Business Media Dordrecht. Source

He K.,Soochow University of China | Hong R.Y.,Soochow University of China | Hong R.Y.,Fuzhou University | Feng W.G.,Nanocom Inc. | Badami D.,University of Waterloo
Powder Technology

Dielectric zinc magnesium titanate (ZMTO) was synthesized by a facile co-precipitation method using TiOSO4 as the Ti source. The decomposition and phase evolvement of the as-prepared precipitates during heat treatment were characterized by thermogravimetry analysis (TGA) and Fourier-transforming infrared (FT-IR) spectroscopy. X-ray diffractometry shows that different pH levels have a significant influence on the crystallization of the as-prepared precipitate due to the magnesium doping content. SEM images and EDS data show that fine hexagonal (Zn, Mg)TiO3 powders with a Mg doping content of 2.29at.% could be obtained at a pH of 9 and a calcination temperature of 800°C. After sintering at 1000°C, hexagonal (Zn, Mg)TiO3 demonstrated a dielectric constant of 26-24 along with a low dielectric loss of 9.82×10-4-6.35×10-4 at measurement frequencies between 108 and 109Hz. © 2013 Elsevier B.V. Source

Wang L.S.,Soochow University of China | Lu H.F.,Soochow University of China | Hong R.Y.,Soochow University of China | Hong R.Y.,Fuzhou University | And 2 more authors.
Powder Technology

This paper provided an economical route to produce composite conductive powders. The aim of this work was to uniformly deposit antimony-doped tin oxide (ATO) nanoparticles onto talc matrix by co-precipitation to prepare Sb-SnO 2/talc (SST) composite conductive powders after calcination. The samples were characterized by X-ray diffraction and scanning electronic microscopy. In order to investigated the mechanism of hydrolysis reaction the precursors of ATO powder were researched by means of thermogravimetric analysis. Each effect of pH, coating ratio, SnCl 4.5H 2O/SbCl 3 mass ratio, hydrolysis temperature, calcination temperature and time on the resistivity of the SST powders was studied. Under the optimum experimental conditions, the resistivity of the composite conductive powders was less than 10Ωcm. © 2012. Source

Lu H.F.,Soochow University of China | Hong R.Y.,Soochow University of China | Hong R.Y.,Nanocom Inc. | Wang L.S.,Soochow University of China | And 2 more authors.
Materials Letters

Antimony-doped tin oxide (ATO) nanorods with tetragonal rutile structure were obtained by calcining coprecipitated precursors with sodium metasilicate nonahydrate and sodium chloride. The as-prepared ATO crystals displayed a rod-like shape. With the increase of Sb-doping concentration, the amount of nanorods decreased and the length of the rod got shorter, while the diameter changed little. When the doping amount reached at n(Sb)/n(Sn) = 5%, the nanorods became quite small (ca. 9 nm in diameter, ca. 25 nm in length). The effect of Sb doping content on the electrical resistivity was also investigated. The electrical resistivity of ATO nanopowders shows a significant decrease just only adding a small amount of Sb doping content. When the Sb doping content reached 5 mol%, the minimum electrical resistivity (0.8 Ω•cm) was obtained. © 2011 Elsevier B.V. All rights reserved. Source

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