Synthesis of rutile and anatase TiO2 nanoparticles from Ti-peroxy compound aqueous solution with polyols

2003 ◽  
Vol 18 (4) ◽  
pp. 797-803 ◽  
Author(s):  
Naofumi Uekawa ◽  
Miki Suzuki ◽  
Takahiro Ohmiya ◽  
Fumihiko Mori ◽  
Yong Jun Wu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Ethylene Glycol ◽  
Specific Surface ◽  
Tio2 Nanoparticles ◽  
Surface Area ◽  
Specific Surface Area ◽  
Single Phase ◽  
Anatase Tio2 ◽  
Oh Groups

Ti-peroxy compound was synthesized from Ti(O-iPr)4 and H2O2. Anatase and rutile TiO2 nanoparticles were prepared by heating the Ti-peroxy compound diluted with a polyol aqueous solution at 368 K for 24 h. In this research, ethylene glycol, glycerin, erythritol, and D-mannitol were used as polyols in the diluting solution. The ratio of anatase/rutile of the TiO2 obtained depended on the polyol concentration in the diluting solution. Furthermore, the polyol concentration at which single-phase anatase could be obtained was lowest when the number of OH groups in the polyol molecule was the highest. With increasing polyol concentration, the obtained TiO2 nanoparticles showed increasing specific surface area and decreasing particle size.

scholarly journals Synthesis of Spherical Silica by Sol-Gel Method and Its Application as Catalyst Support

2011 ◽  
Vol 10 (2) ◽  
pp. 25
Author(s):  
Anirut Leksomboon ◽  
Bunjerd Jongsomjit
Keyword(s):  
Particle Size ◽  
Ethylene Glycol ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Weight Ratio ◽  
Gel Method ◽  
Sol Gel Method ◽  
Spherical Silica

In this present study, the spherical silica support was synthesized from tetraethyloxysilane (TEOS), water, sodium hydroxide, ethylene glycol and n-dodecyltrimethyl ammonium bromide (C12TMABr). The particle size was controlled by variation of the ethylene glycol co-solvent weight ratio of a sol-gel method preparation in the range of 0.10 to 0.50. In addition, the particle size apparently increases with high weight ratio of co-solvent, but the particle size distribution was broader. The standard deviation of particle diameter is large when the co-solvent weight ratio is more than 0.35 and less than 0.15. However, the specific surface area was similar for all weight ratios ranging from 1000 to 1300 m2/g. The synthesized silica was spherical and has high specific surface area. The cobalt was impregnated onto the obtained silica to produce the cobalt catalyst used for CO2 hydrogenation.</

Influence of Synthesis Condition on N2 Adsorption Characteristics of Anatase TiO2 Particles Prepared in an Aqueous Solution

2008 ◽  
Vol 388 ◽  
pp. 103-106
Author(s):  
Yoshitake Masuda ◽  
Kazumi Kato
Keyword(s):  
Aqueous Solution ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Anatase Tio2 ◽  
N2 Adsorption ◽  
Tio2 Particles ◽  
Bet Specific Surface Area ◽  
Desorption Isotherms ◽  
Adsorption Desorption

TiO2 was crystallized to form particles in aqueous solutions containing ammonium hexafluorotitanate and boric acid. XRD diffraction patterns indicated they were in a single phase of anatase TiO2. TiO2 particles prepared at 90 °C exhibited N2 adsorption-desorption isotherms of type IV. BET specific surface area of the particles was estimated to 13 m2/g. On the other hand, TiO2 particles prepared at 50 °C exhibited N2 adsorption-desorption isotherms of type I. BET specific surface area of the particles was estimated to 168 m2/g. Crystal growth of TiO2 was strongly affected by synthesis temperature. Nano-sized pores or surface structure of TiO2 particles prepared at 50 °C would increase N2 adsorption volume to realize high BET specific surface area. Additionally, aqueous solution process described here had an advantage that TiO2 crystallized at ambient temperature. Anatase TiO2 was prepared without annealing at high temperature which caused aggregation of particles and disappearance of surface nanostructures. The particles with large surface area can be thus utilized for catalyst, cosmetic, photocatalyst, dye-sensitized solar cell or sensors.

Physical Properties Variability of Zinc Powders Obtained by Electrochemical Method

2021 ◽  
Vol 316 ◽  
pp. 689-693
Author(s):  
K.D. Naumov ◽  
V.G. Lobanov
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Bulk Density ◽  
Surface Area ◽  
Specific Surface Area ◽  
Current Density ◽  
Zinc Concentration ◽  
Regulatory Change ◽  
Average Particle ◽  
Zinc Powders

The aim of this paper is to establish a regulatory change of zinc powders key physicochemical properties with varying electroextraction conditions. It was studied influence zinc concentration, alkali concentration and current density. Quantitative dependencies of zinc powders particle size and specific surface area from mentioned electroextraction parameters are shown. At increasing of zinc concentration, decreasing of NaOH concentration and decreasing of current density of powders particle size growth, correspondingly specific surface area is declined. It is indicated, that electrolytic zinc powders bulk density varies from 0.61 g/cm3 to 0.75 g/cm3 with a decrease of average particle size from 121 μm to 68 μm. In comparison, spherical powders bulk density used in various industries is currently 2.45-2.6 g/cm3. In all experiments, metal zinc content varied in the range of 91.1-92.5%, the rest - ZnO. To a greater extent, this indicator depends on powder washing quality from alkali and storage conditions.

Preparation of Nanosize Anatase TiO2 Powders by Hydrothermal Synthesis

2007 ◽  
Vol 336-338 ◽  
pp. 2017-2020 ◽  
Author(s):  
Fan Yong Ran ◽  
Wen Bin Cao ◽  
Yan Hong Li ◽  
Xiao Ning Zhang
Keyword(s):  
Grain Size ◽  
Hydrothermal Synthesis ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Reaction Temperature ◽  
Reaction System ◽  
Anatase Tio2 ◽  
Holding Time ◽  
Precursor Concentration

Nanosize anatase TiO2 powders have been synthesized by hydrothermal synthesis by using technical grade TiOSO4 as precursor and urea as precipitating agent. The initial pressure of the reaction system was set at 6 MPa. Stirring speed was fixed at 300r/min. The reaction system reacted at the temperature ranged from 110 to 150°C for holding 2hrs to 8hrs and the concentration of the precursor was ranged from 0.25M to1.5M. XRD patterns show that the synthesized powders are in the form of anatase phase. Calculated grain size is ranged from 6.7 to 8.9nm by Scherrer method from the line broadening of the (101) diffraction peak of anatase. The specific surface area of the powders synthesized under different conditions is ranged from 124 to 240m2/g. The grain size of the powders increases with the increase of the reaction temperature, holding time and precursor concentration, respectively. The specific surface area decreases with the increase of reaction temperature and holding time, and does not obviously change with the change of precursor concentration when the concentration of the precursor is less than 1M. However, when the concentration is higher than 1M, the specific surface area will decrease quickly with the increase of the precursor concentration. XRD and DSC-TG analysis shows that the synthesized anatase TiO2 will begin to transform to rutile TiO2 at about 840°C. When heated to 1000°C for holding 1h, the anatase powders will transform to rutile completely.

Influence of Powder Particle Size of Slurries on Mechanical Properties of Porous Hydroxyapatite Ceramics

2005 ◽  
Vol 284-286 ◽  
pp. 365-368 ◽  
Author(s):  
Yin Zhang ◽  
Yoshiyuki Yokogawa ◽  
Tetsuya Kameyama
Keyword(s):  
Particle Size ◽  
Flexural Strength ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Particle Sizes ◽  
Wet Milling ◽  
Median Particle Size ◽  
Powder Characteristics ◽  
Median Particle

The effect of different particle sizes on the flexural strength and microstructure of three different types of hydroxyapatite (HAp) powders was studied. The powder characteristics of laboratory synthesized HAp powder (Lab1 and Lab2) were obtained through a wet milling method, and the median particle size and the specific surface area of powders are different with the dryness period. The median particle sizes of Lab1 and Lab2 are 0.34 µm and 0.74 µm, and the specific surface areas of Lab1 and Lab2 are 38.01 m2/g and 19.77 m2/g. The commercial HAp had median particle size of 1.13 µm and specific surface area of 11.62m2/g. The different powder characteristics affected the slip characteristics, and the flexural strength and microstructure of the sintered porous HAp bodies are also different. The optimum value for the minimum viscosity in these present HAp slip with respect to its solid loading and the optimum amount of the deflocculant were investigated. The flexural strengths of the porous HAp ceramics prepared by heating at 1200°C for 3 hrs in air were 17.59 MPa for Lab1 with a porosity of 60.48％, 10.51 MPa for Lab2 with a porosity of 57.75％, and 3.92 MPa for commercial HAp with a porosity of 79.37％.

scholarly journals Adsorption of Ammonium Nitrogen from Aqueous Solution on Chemically Activated Biochar Prepared from Sorghum Distillers Grain

2019 ◽  
Vol 9 (23) ◽  
pp. 5249 ◽  
Author(s):  
Derlin Hsu ◽  
Changyi Lu ◽  
Tairan Pang ◽  
Yuanpeng Wang ◽  
Guanhua Wang
Keyword(s):  
Aqueous Solution ◽  
Specific Surface ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Specific Surface Area ◽  
Adsorption Process ◽  
Ammonium Nitrogen ◽  
Activated Biochar ◽  
Distillers Grain ◽  
Kinetics And Isotherms

Chemically activated biochars prepared from sorghum distillers grain using two base activators (NaOH and KOH) were investigated for their adsorption properties with respect to ammonium nitrogen from aqueous solution. Detailed characterizations, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry (TG), and specific surface area analyses, were carried out to offer a broad evaluation of the prepared biochars. The results showed that the NaOH- and KOH-activated biochars exhibited significantly enhanced adsorption capacity, by 2.93 and 4.74 times, respectively, in comparison with the pristine biochar. Although the NaOH-activated biochar possessed larger specific surface area (132.8 and 117.7 m2/g for the NaOH- and KOH-activated biochars, respectively), the KOH-activated biochar had higher adsorption capacity owing to its much higher content of functional groups. The adsorption kinetics and isotherms of the KOH-activated biochar at different temperatures were further studied. The biochar had a maximum adsorption capacity of 14.34 mg/g at 45 °C, which was satisfactory compared with other biochars prepared using different feedstocks. The adsorption process followed pseudo-second-order kinetics, and chemical adsorption was the rate-controlling step. The equilibrium data were consistent with the Freundlich isotherm, and the thermodynamic parameters suggested that the adsorption process was endothermic and spontaneous. Consequently, this work demonstrates that chemically activated biochar from sorghum distillers grain is effective for ammonium nitrogen removal.

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