scholarly journals One-Step Synthesis of Spherical γ-Fe2O3 Nanopowders and the Evaluation of Their Photocatalytic Activity for Orange I Degradation

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Chunhua Liang ◽  
Hui Liu ◽  
Jianmin Zhou ◽  
Xiaochun Peng ◽  
Haizhou Zhang
Keyword(s):  
Particle Size ◽  
Reaction Time ◽  
Synthesis Method ◽  
Total Pore Volume ◽  
Xrd Analysis ◽  
Bet Surface Area ◽  
Particle Sizes ◽  
Aqueous Synthesis ◽  
One Step ◽  
The One

Maghemite (γ-Fe2O3) nanopowders were synthesized under aeration (oxidizing) conditions by aqueous synthesis in this study. The microstructures of the prepared powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and BET-BJH. The XRD analysis and the chemical experiments showed that well-crystallized γ-Fe2O3 nanoparticles were successfully obtained with a mean particle size of approximately 17 nm. The prepared γ-Fe2O3 was spherical with a BET surface area of 14.357 m2/g and a total pore volume of 0.050 cm3/g. Varying the reaction conditions, such as pH, temperature, and reaction time, we obtained crystallized γ-Fe2O3 powders with different crystallization extent and different particle sizes. When the pH of the reaction suspension was increased, the reaction time was prolonged, and the reaction temperature was increased, the γ-Fe2O3 powders underwent superior crystallization and had larger particle sizes. All the obtained γ-Fe2O3 powders had significant photocatalytic activities under both UV and visible light irradiation for Orange I degradation, and the powders with better crystallization and larger particle size had relatively lower activities for Orange I photocatalytic degradation. The one-step aqueous synthesis method presented in this paper may provide an advantageous pathway to synthesize large quantities of this important iron oxide.

ChemInform Abstract: Cycling Properties of Sc- and Ce-Doped NaAlH4Hydrogen Storage Materials Prepared by the One-Step Direct Synthesis Method.

ChemInform ◽  
2009 ◽  
Vol 40 (22) ◽  
Author(s):  
Borislav Bogdanovic ◽  
Michael Felderhoff ◽  
Andre Pommerin ◽  
Ferdi Schueth ◽  
Nick Spielkamp ◽  
...  
Keyword(s):  
Direct Synthesis ◽  
Synthesis Method ◽  
Storage Materials ◽  
One Step ◽  
The One

scholarly journals Effect of Nanosilica on the Fresh Properties of Cement-Based Grouting Material in the Portland-Sulphoaluminate Composite System

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Shengli Li ◽  
Tingting Xu
Keyword(s):  
Particle Size ◽  
Apparent Density ◽  
Composite System ◽  
Setting Time ◽  
Xrd Analysis ◽  
Hydration Reaction ◽  
Particle Sizes ◽  
Fresh Properties ◽  
Air Content ◽  
Grouting Material

The effect of NS particle size and content on the fresh properties of the grouting material based on the portland-sulphoaluminate composite system was analyzed. The experimental results indicated that air content increased and apparent density decreased, with increased NS content, but the NS particle sizes have minimal effect on the air content and apparent density. The setting time of mortar was significantly shortened, with increased NS content; however, NS particle sizes had little influence on the setting time. The effect of fluidity on the mortars adding NS with particle size of 30 nm is larger than NS with particle sizes of 15 and 50 nm and the fluidity decreased with increased NS content, but the fluidity of mortars with the particle sizes of 15 and 50 nm is almost not affected by the NS content. XRD analysis shows that the formation of ettringite was promoted and the process of hydration reaction of cement was accelerated with the addition of NS. At the microscopic level, the interfacial transition zone (ITZ) of the grouting material became denser and the formation of C-S-H gel was promoted after adding NS.

scholarly journals Efficient Preparation and Performance Characterization of the HMX/F2602 Microspheres by One-Step Granulation Process

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Conghua Hou ◽  
Xinlei Jia ◽  
Jingyu Wang ◽  
Yingxin Tan ◽  
Yuanping Zhang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermal Stability ◽  
Particle Size ◽  
Particle Morphology ◽  
Xrd Analysis ◽  
Impact Sensitivity ◽  
Scanning Calorimetry ◽  
Granulation Process ◽  
One Step ◽  
The Impact

A new one-step granulation process for preparing high melting explosive- (HMX-) based PBX was developed. HMX/F2602 microspheres were successfully prepared by using HMX and F2602 as the main explosive and binder, respectively. The particle morphology, particle size, crystal structure, thermal stability, and impact sensitivity of the as-prepared HMX/F2602 microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analyzer, differential scanning calorimetry (DSC), and impact sensitivity test, respectively. The SEM analysis indicated successful coating of F2602 on the surface of HMX, and the resulting particles are ellipsoidal or spherical with a median particle size of 940 nm; the XRD analysis did not show any change in the crystal structure after the coating and still has β-HNX crystal structure; according to the DSC analysis, HMX/F2602 prepared by the new method has better thermal stability compared to that prepared by the water suspension process. The impact sensitivity of HMX/F2602 prepared by this one-step granulation process decreased, and its characteristic height H50 increased from 37.62 to 40.13 cm, thus significantly improving the safety performance. More importantly, this method does not need the freeze-drying process after recrystallization, thus increasing the efficiency by 2 to 3 times.

scholarly journals Synthesis of Hydrophobic Mesoporous Material MFS and Its Adsorption Properties of Water Vapor

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Guotao Zhao ◽  
Zhenxiao Zhao ◽  
Junliang Wu ◽  
Daiqi Ye
Keyword(s):  
Water Vapor ◽  
Surface Area ◽  
Mesoporous Material ◽  
High Surface ◽  
Synthesis Method ◽  
Gravimetric Method ◽  
Total Pore Volume ◽  
Adsorption Properties ◽  
Bet Surface Area ◽  
Mcm 41

Fluorine-containing hydrophobic mesoporous material (MFS) with high surface area is successfully synthesized with hydrothermal synthesis method by using a perfluorinated surfactant SURFLON S-386 template. The adsorption properties of water vapor on the synthesized MFS are also investigated by using gravimetric method. Results show that SEM image of the MFS depicted roundish morphology with the average crystal size of 1-2 μm. The BET surface area and total pore volume of the MFS are 865.4 m2 g−1and 0.74 cm3 g−1with a narrow pore size distribution at 4.9 nm. The amount of water vapor on the MFS is about 0.41 mmol g−1at 303 K, which is only 52.6% and 55.4% of MCM-41 and SBA-15 under the similar conditions, separately. The isosteric adsorption heat of water on the MFS is gradually about 27.0–19.8 kJ mol−1, which decreases as the absorbed water vapor amount increases. The value is much smaller than that on MCM-41 and SBA-15. Therefore, the MFS shows more hydrophobic surface properties than the MCM-41 and SBA-15. It may be a kind of good candidate for adsorption of large molecule and catalyst carrier with high moisture resistance.

Palladium-Silica Organic-Inorganic Membrane Materials via a Sol-Gel Process: Preparation and Properties Calcined under H2 Atmosphere

2017 ◽  
Vol 727 ◽  
pp. 889-894
Author(s):  
Jing Yang ◽  
Lin Yu Li ◽  
Hai Yun Hou ◽  
Zhi Tong
Keyword(s):  
Particle Size ◽  
Sol Gel ◽  
Total Pore Volume ◽  
Energy Dispersive Spectrum ◽  
Bet Surface Area ◽  
Molar Ratio ◽  
Inorganic Membrane ◽  
X Ray Diffraction ◽  
Membrane Materials ◽  
Sol Gel Process

Pd-doped SiO2 organic-inorganic membrane materials were prepared via a sol-gel process. The sol stability is characterized by sol particle size and zeta potential analysis. And the properties of the Pd-doped SiO2 organic-inorganic membrane materials are investigated by X-ray diffraction (XRD), fourier transform infrared (FTIR), energy dispersive spectrum (EDS) analysis and N2 absorption-adsorption measurement. The results showed that the sol particle size distributions are relatively narrow. With the increase of Pd content, the sol particle sizes slightly increase and the zeta potentials decreases until the palladium/tetraethylorthosilicate molar ratio closes to the isoelectric point. After calcined at 350 °C under H2 atmosphere, the added PdCl2 is reduced to metallic Pd0 completely, and the hydrophobic Si−CH3 groups exist in the SiO2 network. The Pd atoms have a lower concentration on the surface and more Pd atoms embedded in the SiO2 matrix. The Pd-doped SiO2 membrane materials calcined at 350 °C with a palladium/tetraethylorthosilicate molar ratio of 0.15 exhibit large BET surface area (up to 683.36 m2/g) and total pore volume (up to 0.386 cm3/g), as well as a mean pore diameter of about 2.26 nm.

Hydrothermal Synthesis of CoFe2O4 Nanoparticles and their Magnetic Properties

2013 ◽  
Vol 821-822 ◽  
pp. 1358-1361 ◽  
Author(s):  
Fan Zhang ◽  
Rui Liang Su ◽  
Li Zhi Shi ◽  
Yang Liu ◽  
Yan Na Chen ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Spinel Ferrite ◽  
Synthesis Method ◽  
Ferrite Nanoparticles ◽  
Particle Sizes ◽  
Naoh Solution ◽  
20 Nm

CoFe2O4 (CFO) nanoparticles was synthesized by a simple hydrothermal method using NaOH solution as a mineralizer at 200 °C for 4 h. It was found that CFO particle sizes decreased firstly and then increased with the increasing of NaOH concentration, and had a minumum value about 10-20 nm when selected 4 mol/L NaOH solution, indicating the NaOH concentration played an important role in controlling the particle size of CFO powders. The room temperature magnetic measurements showed that the saturation magnetization value was 48 emu/g, which is less than the bulk value. The synthesis method is possible to be a general approach for the preparation of other spinel ferrite nanoparticles.

scholarly journals Eco Friendly Synthesis of Carbon Dot by Hydrothermal Method for Metal Ions Salt Identification

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7604
Author(s):  
Hasan Shabbir ◽  
Tomasz Tokarski ◽  
Ditta Ungor ◽  
Marek Wojnicki
Keyword(s):  
Metal Ion ◽  
Hydrothermal Reaction ◽  
Synthesis Method ◽  
Emission Spectra ◽  
Carbon Quantum Dots ◽  
Photoluminescence Properties ◽  
Step Method ◽  
Synthesis Time ◽  
One Step ◽  
The One

In this work, we report the synthesis method of carbon quantum dots (CDs) using the one-step method for fast and effective metal ion determination. Ascorbic acid was used as an inexpensive and environmentally friendly precursor. High-pressure and high-temperature reactors were used for this purpose. Microscopic characterization revealed the size of CDs was in the range of 2–6 nm and they had an ordered structure. The photoluminescence properties of the CDs depend on the process temperature, and we obtained the highest PL spectra for 6 h of hydrothermal reaction. The maximum emission spectra depend poorly on synthesis time. Further characterization shows that CDs are a good contender for sensing Fe3+ in aqueous systems and can detect concentrations up to 0.49 ppm. The emission spectra efficiency was enhanced by up to 200% with synthesis time.

scholarly journals Effects of Cobalt Loading, Particle Size, and Calcination Condition on Co/CNT Catalyst Performance in Fischer–Tropsch Reactions

Symmetry ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 7 ◽  
Author(s):  
Omid Akbarzadeh ◽  
Noor Mohd Zabidi ◽  
Yasmin Abdul Wahab ◽  
Nor Hamizi ◽  
Zaira Chowdhury ◽  
...  
Keyword(s):  
Particle Size ◽  
Fixed Bed ◽  
Xrd Analysis ◽  
Bet Surface Area ◽  
Fischer Tropsch ◽  
Strong Electrostatic Adsorption ◽  
Transmission Electron ◽  
Co Conversion ◽  
Cobalt Loading ◽  
Temperature Programmed

The strong electrostatic adsorption (SEA) method was applied to the synthesis of a cobalt (Co) catalyst on a multi-walled carbon nanotube (CNT) support. In order to uptake more of the cobalt cluster with higher dispersion, the CNT was functionalized via acid and thermal treatment. The Co/CNT catalyst samples were characterized by a range of methods including the Brunauer–Emmet–Teller (BET) surface area analyzer, transmission electron microscopy (TEM), X-ray powder diffraction (XRD) analysis, atomic absorption spectroscopy (AAS), and H2-temperature programmed reduction (H2-TPR) analysis. The data from the TEM images revealed that the catalyst was highly dispersed over the external and internal walls of the CNT and that it demonstrated a narrow particle size of 6–8 nm. In addition, the data from the H2-TPR studies showed a lower reduction temperature (420 °C) for the pre-treated catalyst samples. Furthermore, a Fischer–Tropsch synthesis (FTS) reaction was chosen to evaluate the Co/CNT catalyst performance by using a fixed-bed microreactor at different parameters. Finally finding the optimum value of the cobalt loading percentage, particle size, and calcination conditions of Co/CNT catalyst resulted in a CO conversion and C5+ selectivity of 58.7% and 83.2%, respectively.

Removal of silicon from green liquor with carbon dioxide in the chemical recovery process of wheat straw soda pulping

TAPPI Journal ◽  
2013 ◽  
Vol 12 (3) ◽  
pp. 35-40 ◽  
Author(s):  
XINXING XIA ◽  
MINGZHU DU ◽  
XIUJUAN GENG
Keyword(s):  
Carbon Dioxide ◽  
Particle Size ◽  
Wheat Straw ◽  
Reaction Temperature ◽  
Recovery Process ◽  
Chemical Recovery ◽  
Step Process ◽  
Green Liquor ◽  
One Step ◽  
The One

Green liquor in the chemical recovery process of wheat straw pulping was treated with carbon dioxide to precipitate silicon by a one-step process and a seeding process to address problems caused by high silicon content. The total silicon removal, the particle size, and the sedimentation performance of silica were investigated. The results showed that the pH of green liquor decreased with increasing amounts of carbon dioxide, becoming stable after the pH decreased to 8.2. Reaction temperature had no significant effect on the removal of silicon. About 99% of silicon removal was achieved at a pH of 9.2 at room temperature. In the one-step process, the particle size increased and the silica sedimentation performance improved with decreasing pH. The particle size decreased and the sedimentation performance improved with increasing reaction temperature. At a pH of 9.5 and reaction temperature of 80°C, the particle size was 10.43 μm. In the seeding process, 40% green liquor was treated with carbon dioxide at 80°C until the pH was about 10.5, then the 40% treated green liquor was mixed with the remaining 60% of green liquor. The mixture was then treated with carbon dioxide at a reaction temperature of 80°C until the pH reached 9.5. In that situation, the particle size reached 14.11 μm. Compared with the one-step process, the particle size of silica generated by the seeding process was bigger and the sedimentation performance was improved.

A solvothermal decomposition process for fabrication and particle sizes control of Bi2S3 nanowires

1999 ◽  
Vol 14 (11) ◽  
pp. 4157-4162 ◽  
Author(s):  
Shu-Hong Yu ◽  
Lei Shu ◽  
Jian Yang ◽  
Zhao-Hui Han ◽  
Yi-Tai Qian ◽  
...  
Keyword(s):  
Reaction Time ◽  
Decomposition Process ◽  
Particle Sizes ◽  
Metal Chalcogenides ◽  
Polar Solvents ◽  
Mild Conditions ◽  
Present Technique ◽  
One Step ◽  
Solvothermal Decomposition ◽  
Influence Of Solvents

A novel one-step solvothermal decomposition process (SDP) was successfully developed for fabrication of Bi2S3 nanowires via a reaction between BiCl3 and thiourea in polar solvents at 140 °C for 6–12 h. The influence of solvents, reaction temperature, and reaction time on the formation of Bi2S3 nanowires was investigated. The yield was as high as 98%. The particle sizes of Bi2S3 nanowires are controlled by the choice of solvents. The possible formation mechanism of Bi2S3 nanowires via the so-called SDP method is proposed. The present technique is expected to synthesize other nanostructural metal chalcogenides under mild conditions.

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