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1.
Khanitta Intarasuwan Pongsaton Amornpitoksuk Sumetha Suwanboon 《Advanced Powder Technology》2013,24(6):999-1005
The urchin-like shape of ZnO powders was prepared by mixing of Zn2+ and NaOH solutions at various mixing rates. In this work, ε-Zn(OH)2 was the first precipitant that was subsequently transformed to ZnO in the alkaline medium during heating. The size of the urchin-like shape of the ZnO powder decreased with a decrease of the mixing rate. The large urchin-like shape also had a large diameter of its hexagonal facet (0 0 0 1) and showed the highest photocatalytic degradative activity on methylene blue. 相似文献
2.
Sumetha Suwanboon Pongsaton Amornpitoksuk Nantakan Muensit 《Ceramics International》2011,37(7):2247-2253
Nanocrystalline ZnO powders were prepared from cetyltrimethylammonium bromide (CTAB)-modified NaOH, NH4OH and (CH2)6N4 solutions. The calcined ZnO powders exhibited a hexagonal structure without any secondary phase. Different shapes of ZnO powders were formed depending on CTAB concentration and type of precipitating agent. As (CH2)6N4 solution was used, rod-like ZnO structure was changed to a spherical shape when CTAB concentration was increased. The widest Eg value of approximately 3.23 eV was obtained from the sample containing the lowest defect concentration. The decolorization efficiency was higher than 90% after irradiating for 90 min and the sample with higher Eg value showed higher decolorization efficiency. 相似文献
3.
Various shapes of ZnO particles were synthesized through a precipitation method as a low cost technique. The morphological changes due to the use of poly(ethylene oxide)-b-poly(propylene oxide) copolymer as a stabilizer and precipitation from pH solutions of 8, 10 and 12 were investigated. The ZnO powder that was prepared from pH 10 showed the highest efficiency for degrading the dyes methylene blue, rhodamine B and reactive orange under backlight fluorescent tubes. This may be due to the highest surface area obtained from precipitation at this pH. These prepared ZnO particles also exhibited antibacterial effects that were stronger on Staphylococcus aureus than on Escherichia coli. 相似文献
4.
T. Rattana S. Suwanboon P. Amornpitoksuk A. Haidoux P. Limsuwan 《Journal of Alloys and Compounds》2009,480(2):603-607
Nanocrystalline Zn1−xFexO (where x = 0, 0.01 and 0.02) powders were successfully synthesized by a precipitation method from citrate-modified zinc nitrate solution. X-ray powder diffraction, Fourier transformed infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy were used to study the structural properties. The optical properties were determined by UV–vis spectrophotometer and luminescent spectrometer. In this study, the optical band gap of nanocrystalline ZnO powder increased from 3.170 eV to 3.214 eV when the Fe concentration in the solution was increased up to 2 mol. %. 相似文献
5.
Iranian Polymer Journal - From a zinc precursor of zinc nitrate hexahydrate and a precipitating agent of sodium hydroxide, zinc oxide (ZnO) was hydrothermally synthesized. Using different... 相似文献
6.
Effect of pH on the morphology and optical properties of modified ZnO particles by SDS via a precipitation method 总被引:1,自引:0,他引:1
ZnO particles were synthesized directly from an aqueous solution of zinc acetate dihydrate in the presence of sodium dodecyl sulfate (SDS) and sodium hydroxide at 70 °C. The morphological changes were investigated in the range of pH 8-12. The hexagonal prism-like shape was formed at pH 8 and 10 by inhibition of growth along the c direction whereas the small rod-like shape was observed at pH 12. The estimated band gap and the room temperature photoluminescence intensity in a visible region are dependent upon the geometrical shape and size of the ZnO particles. 相似文献
7.
Chat Pholnak Monthon Lertworapreecha Sumetha Suwanboon 《Journal of Experimental Nanoscience》2016,11(17):1320-1330
The variation in morphology of zinc oxide (ZnO) with the pH of 0.05 M Zn(NO3)2 and 1.00 M NaOH aqueous solutions is demonstrated. Microstructured ZnO ranges from cuboid to spindle as the pH is reduced from 12 to 9. The ratio of visible-to-UV peak from photoluminescence spectra is also decreased, whereas the energy gap calculated from UV-Vis spectra remains comparable. Furthermore, nanospheroids and microellipsoid are, respectively, obtained when the molar concentration of NaOH is reduced to 0.20 and 0.10 M for the synthesis with the pH of 7. Due to their large surface-to-volume ratio, these ZnO nanospheroids exhibit a higher antibacterial activity than that of commercial ZnO in the disc diffusion method. According to this method as well as the minimal inhibitory concentration measurement, the effectiveness is substantial in the case of Staphylococcus aureus and Escherichia coli. By contrast, the inhibitions of Klebsiella pneumoniae, Salmonella typhimurium and Pseudomonas aeruginasa are barely observed. 相似文献
8.
Structural and optical properties of mechanically milled La-doped ZnO powders are presented in this paper. The Zn1−xLaxO phase formed when x varied in a range of 0.02-0.06 and milled at 400 rpm for 20 h. The secondary La2O3 phase occurred with an increase of La content. The crystallite and particle size decreased as a function of La content as x = 0-0.14 due to the effect of Zener pinning and solute drag. The absorption edge shifted to a lower wavelength when La content was increased to x = 0.14 because of the size effect. The energy band gap of Zn1−xLaxO powders varied in a range of 2.96-3.12 eV depending on the crystallite size. The broad emission bands in a visible region centered at about 640 nm are attributed to oxygen deficiency. 相似文献
9.
Sumetha Suwanboon Pongsaton AmornpitoksukPhuwadol Bangrak 《Ceramics International》2011,37(1):333-340
Zn1−xTixO (x = 0, 0.01, 0.03 and 0.05) nanoparticles were prepared by high-energy ball milling at 400 rpm. The milled powders were characterized by X-ray diffractometer (XRD) and the results exhibited that Ti-doped ZnO nanoparticles consisted of single phase with hexagonal structure when the mixtures of ZnO and TiO2 powders were milled for 20 h. The crystallite size reduced as a function of the doping content and milling time from 1 to 10 h then increased after milling for 20 h and when the annealing temperature increased. The strain changed inversely to the crystallite size. A wider band-gap was obtained by increasing the doping content and annealing temperature because of a reduction in defect concentration. Both ZnO- and Ti-doped ZnO nanoparticles caused damage to S. aureus, E. coli, P. mirabilis, S. typhi and P. aeruginosa. 相似文献
10.
Sirinya Chantarak Jooyoung Chang Sumetha Suwanboon Saad Riyajan 《Journal of Porous Materials》2018,25(5):1391-1399
Mesoporous silica nanoparticles (MSNPs) have been used in variety of applications due to their morphology and porous structure. This work reports the one-pot synthesis of ultrahydrophobic MSNPs using N-cetyl-n,n,n trimethyl ammonium bromide as a cationic surfactant template and ethanol (EtOH) as a cosolvent to form mesopores in the MSNPs. The effects of EtOH on the size and the pore structure of the MSNPs were studied by scanning electron microscopy and transmission electron microscopy. The results show that an addition of EtOH led to an enlargement of the MSNPs and a change in pore structure from a lamellar structure to a radially oriented structure. Co-condensation with two different types of fluoroalkyl silanes; trimethyl(fluoromethyl)silane, and trichloro(1H,1H,2H,2H-perfluorooctyl)silane provided low surface energy MSNPs with a core–shell structure. An assembly on the surface of these F-MSNPs generated nanostructure surface roughness rendering an improvement in surface wettability with water contact angle of 158.6°, which is a characteristic of oleophobic and ultrahydrophobic material. 相似文献