scholarly journals Synthesis and Characterization of Fe3O4@SiO2@mesoporous-SiO2 Materials

2021 ◽  
Author(s):  
Shuiping LI
Keyword(s):  
Average Pore Size ◽  
Average Particle Size ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Template Method ◽  
Average Particle ◽  
Step Method ◽  
Average Pore ◽  
Thermal Synthesis ◽  
Mesoporous Sio2

In this work, a magnetic Fe3O4@SiO2@mesoporous-SiO2 (F@S@m-S) material was successfully prepared by a three-step method: firstly, Fe3O4 particles were synthesized through hydro-thermal synthesis process; secondly, Fe3O4@SiO2 materials were fabricated via a template method using tetraethyl orthosilicate (TEOS) as silicon sources and cetyltrimethylammonium chloride (CTAC) as templates; lastly, F@S@m-S materials were prepared through a template method as well. The influence of TEOS/CTAC molar ratio on the morphology and mesostructure was investigated. The product was characterized by Fourier-transform Infrared Spectroscopy (FT-IR), small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), transmission electron microscope (TEM), and N2 adsorption-desorption. The results demonstrated that F@S@m-S materials have a well spherical morphology and a typical mesostructure. The increase of TEOS/CTAC molar ratio can improve the mesostructure and crystal form of F@S@m-S materials. The average particle size, specific surface area, average pore size and pore volume of F@[email protected] materials are 130 nm, 77.1 m2/g, 9.2 nm and 0.1668 cm2/g, respectively.

Research on Preparation of Mesoporous Zeolite by Template Method

2010 ◽  
Vol 158 ◽  
pp. 204-210 ◽  
Author(s):  
Zhi Jun Ma ◽  
Yi Min Zhu ◽  
Yan Jun Li ◽  
Xin Fang
Keyword(s):  
Pore Size ◽  
Raw Materials ◽  
Average Pore Size ◽  
Pure Aluminum ◽  
Sodium Aluminate ◽  
Synthesis Process ◽  
Template Method ◽  
Mesoporous Zeolite ◽  
Synthesis Mechanism ◽  
Average Pore

In this paper, the preparation of mesoporous zeolite by template method is studied that the mesoporous zeolite is made up of pure silica source and pure aluminum source. The synthesis mechanism of mesoporous zeolite is investigated according to the characterization results of FTIR, SEM and N2 adsorption-desorption. The results shows that the water glass and sodium aluminate as the partial raw materials of synthesis process, P123 as the template, reaction at 42°C for 20h, aging at 54°C for 48 h, calcining at 550°C for 5 h. The average pore size of prepared mesoporous zeolite is 6.4nm and the specific surface area is 394.65m2/g. The FTIR shows that the microstructure of the prepared samples is similar to zeolite ore, and the SEM result indicates that the micromorphology of the product is uniform and pore size is within the mesoporous range.

A Rapid One-Step Method for Gold Nanoparticles Synthesis with Polyethylene Glycol 200

2019 ◽  
Vol 11 (10) ◽  
pp. 1445-1450
Author(s):  
Xianbo Mou ◽  
Danni Sheng ◽  
Yabin Zhu ◽  
Ruixia Hou ◽  
Mi Zhou ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Average Particle Size ◽  
Stability Study ◽  
Synthesis Process ◽  
Average Particle ◽  
Uv Spectrum ◽  
Step Method ◽  
Transmission Electron ◽  
Polyethylene Glycol 200 ◽  
One Step

Because of their unique and excellent properties, gold nanoparticles (GNPs) have been widely used in biological monitoring, cosmetics and clinical fields. In this study, PEG200, as a component, and ascorbic acid, as a reducing agent, were used to develop a rapid one-step method for GNPs synthesis at room temperature. The effect of PEG200 on GNPs synthesis and tolerance of GNPs to some common solvents were also investigated. The whole synthesis process was completed within one hour, and transmission electron microscope (TEM), dynamic light scattering (DLS) and UV-Vis characterization showed that the GNPs synthesized by this method had mono dispersity, a strong absorption peak at 522 nm, with an average particle size of 20.38 nm. Stability study showed that the color and UV spectrum of GNPs solution did not change significantly within 90 days. Moreover, its strong tolerance to PB (0.1 M), NaCl (0.9%) and TE solutions was also observed. This method avoids high temperature process, reduces the difficulty of condition control, and can provide immediate PEG-GNPs synthesis for some special occasions, and the strong solution tolerance ensures its great potential application in many fields.

scholarly journals Green synthesis: Proposed mechanism and factors influencing the synthesis of platinum nanoparticles

2020 ◽  
Vol 9 (1) ◽  
pp. 386-398 ◽  
Author(s):  
Mahmood S. Jameel ◽  
Azlan Abdul Aziz ◽  
Mohammed Ali Dheyab
Keyword(s):  
Green Synthesis ◽  
Reaction Temperature ◽  
Platinum Nanoparticles ◽  
Energy Requirement ◽  
Average Particle Size ◽  
High Energy ◽  
Energy Utilization ◽  
Critical Parameters ◽  
Synthesis Process ◽  
Average Particle

AbstractPlatinum nanoparticles (Pt NPs) have attracted interest in catalysis and biomedical applications due to their unique structural, optical, and catalytic properties. However, the conventional synthesis of Pt NPs using the chemical and physical methods is constrained by the use of harmful and costly chemicals, intricate preparation requirement, and high energy utilization. Hence, this review emphasizes on the green synthesis of Pt NPs using plant extracts as an alternative approach due to its simplicity, convenience, inexpensiveness, easy scalability, low energy requirement, environmental friendliness, and minimum usage of hazardous materials and maximized efficiency of the synthesis process. The underlying complex processes that cover the green synthesis (biosynthesis) of Pt NPs were reviewed. This review affirms the effects of different critical parameters (pH, reaction temperature, reaction time, and biomass dosage) on the size and shape of the synthesized Pt NPs. For instance, the average particle size of Pt NPs was reported to decrease with increasing pH, reaction temperature, and concentration of plant extract.

scholarly journals High-Temperature Synthesis of Metal–Matrix Composites (Ni-Ti)-TiB2

2021 ◽  
Vol 11 (5) ◽  
pp. 2426
Author(s):  
Vladimir Promakhov ◽  
Alexey Matveev ◽  
Nikita Schulz ◽  
Mikhail Grigoriev ◽  
Andrey Olisov ◽  
...  
Keyword(s):  
High Temperature ◽  
Composite Materials ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Average Particle Size ◽  
Synthesis Process ◽  
Average Particle ◽  
Temperature Synthesis ◽  
High Temperature Synthesis

Currently, metal–matrix composite materials are some of the most promising types of materials, and they combine the advantages of a metal matrix and reinforcing particles/fibres. Within the framework of this article, the high-temperature synthesis of metal–matrix composite materials based on the (Ni-Ti)-TiB2 system was studied. The selected approaches make it possible to obtain composite materials of various compositions without contamination and with a high degree of energy efficiency during production processes. Combustion processes in the samples of a 63.5 wt.% NiB + 36.5 wt.% Ti mixture and the phase composition and structure of the synthesis products were researched. It has been established that the synthesis process in the samples proceeds via the spin combustion mechanism. It has been shown that self-propagating high-temperature synthesis (SHS) powder particles have a composite structure and consist of a Ni-Ti matrix and TiB2 reinforcement inclusions that are uniformly distributed inside it. The inclusion size lies in the range between 0.1 and 4 µm, and the average particle size is 0.57 µm. The obtained metal-matrix composite materials can be used in additive manufacturing technologies as ligatures for heat-resistant alloys, as well as for the synthesis of composites using traditional methods of powder metallurgy.

Nanosized Hydroxyapatite Powder Synthesized from Eggshell and Phosphoric Acid

2007 ◽  
Vol 7 (11) ◽  
pp. 4061-4064 ◽  
Author(s):  
Sang-Jin Lee ◽  
Young-Soo Yoon ◽  
Myung-Hyun Lee ◽  
Nam-Sik Oh
Keyword(s):  
Phosphoric Acid ◽  
Heating Temperature ◽  
Average Particle Size ◽  
Stoichiometric Composition ◽  
Synthesis Process ◽  
Average Particle ◽  
Mixing Ratio ◽  
Powder Synthesis ◽  
Chemical Route ◽  
Milling Method

The present research describes synthesis of highly sinterable, nano-sized hydroxyapatite (HAp) powders using a wet chemical route with recycled eggshell and phosphoric acid as calcium and phosphorous sources. The raw eggshell was easily turned to CaO by the calcining process, and phosphoric acid was mixed with the calcined eggshell by the wet, ball-milling method. The crystalline development and microstructures of the synthesized powders and sintered samples were examined by X-ray diffractometry and scanning electron microscopy, respectively. The observed phases on the powder synthesis process were dependent on the mixing ratio (wt%) of the calcined eggshell to phosphoric acid and the heating temperature. The ball-milled, nano-sized HAp powder, which has an average particle size of 70 nm, was fully densified at 1300 °C for 1h. The Ca/P ratio for stoichiometric composition of HAp was controlled by adjustment of the mixing ratio.

PHOTOCATALYTIC REMOVAL OF PHENOL OVER MESOPOROUS ZnO/TiO2 COMPOSITES

2018 ◽  
Vol 80 (2) ◽  
Author(s):  
Klinsmann Cheong Lee Khang ◽  
Mohd Hayrie Mohd Hatta ◽  
Siew Ling Lee ◽  
Leny Yuliati
Keyword(s):  
Pore Size ◽  
Uv Light ◽  
Average Pore Size ◽  
Anatase Tio2 ◽  
Light Irradiation ◽  
Molar Ratio ◽  
Average Pore ◽  
Uv Light Irradiation ◽  
Photocatalytic Removal ◽  
Mesoporous Zno

A series of mesoporous ZnO/TiO2 composites were successfully synthesized using cetyltrimethylammonium bromide surfactant. The composites of different Zn:Ti molar ratios (0.5:1, 0.75:1, and 1:1) were prepared by impregnating ZnO onto mesoporous TiO2. XRD results verified co-existence of both anatase TiO2 and hexagonal wurtzite ZnO in the ZnO/TiO2 composites. Based on the Tauc plots, all the composites showed almost the same band gap energy of approximately 3.21 eV. The fourier transform infrared spectroscopy results successful covering of ZnO on the surface of the TiO2 as the hydrophilicity property of TiO2 decreased remarkably with the loading of ZnO in the composites. N2 adsorption-desorption isotherms of the samples exhibited type-IV isotherm with a hysteresis loop. The Barrett-Joyner-Halenda pore size distribution revealed that the average pore size of the composites was around 3.6 nm, indicating the formation of mesopores dominantly in the samples. The photocatalytic removal of phenol over the samples under UV light irradiation after 3 h decreased in the order: ZnO/TiO2 composites > anatase TiO2 (with surfactant) > anatase TiO2 (without surfactant) > ZnO. The composite with Zn:Ti molar ratio of 0.75:1 has achieved the highest photocatalytic activity of 36.5% in the removal of phenol under UV light irradiation for 3 h.

scholarly journals Effect of soil textural characteristics on longitudinal dispersion in saturated porous media

2021 ◽  
Vol 69 (2) ◽  
pp. 161-170
Author(s):  
Mojtaba G. Mahmoodlu ◽  
Amir Raoof ◽  
Martinus Th. van Genuchten
Keyword(s):  
Particle Size ◽  
Dispersion Coefficient ◽  
Average Particle Size ◽  
Longitudinal Dispersion ◽  
Average Particle ◽  
Sand Sample ◽  
Average Pore ◽  
Advection Dispersion ◽  
Strong Positive Relationship

Abstract This study focuses on the effects of soil textural heterogeneity on longitudinal dispersion under saturation conditions. A series of solute transport experiments were carried out using saturated soil columns packed with two filter sands and two mixtures of these sands, having d50 values of 95, 324, 402, and 480 µm, subjected to four different steady flow rates. Values of the dispersion coefficient (D) were estimated from observed in-situ distributions of calcium chlo-ride, injected as a short nonreactive tracer pulse, at four different locations (11, 18, 25, 36 cm). Analyses of the observed distributions in terms of the standard advection-dispersion equation (ADE) showed that D increased nonlinearly with travel distance and higher Peclet numbers+. The dispersion coefficient of sand sample S1 with its largest average particle size (d 50) was more affected by the average pore-water velocity than sample S4 having the smallest d 50. Results revealed that for a constant velocity, D values of sample S1 were much higher than those of sample S4, which had the smallest d 50. A correlation matrix of parameters controlling the dispersion coefficient showed a relatively strong positive relationship between D and the Peclet number. In contrast, almost no correlation was evident between D and porosity as well as grain size. The results obtained with the four sandy matrices were consistent and proved that the dispersion coefficient depends mainly on the particle size.

scholarly journals A Comparative Study of Nanostructures of CuO/Cu2O Fabricated via Potentiostatic and Galvanostatic Anodization

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
S. Mary Margaret ◽  
Albin John P. Paul Winston ◽  
S. Muthupandi ◽  
P. Shobha ◽  
P. Sagayaraj
Keyword(s):  
Thermal Stability ◽  
Comparative Study ◽  
Aqueous Electrolyte ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Molecular Vibration ◽  
Synthesis Process ◽  
Average Particle ◽  
Good Crystallinity ◽  
Cu Foil

A detailed comparative study on the synthesis process of coral-like CuO/Cu2O nanorods (NRs) and nanopolycrystals (NPCs) fabricated on Cu foil employing aqueous electrolyte via potentiostatic (POT) and galvanostatic (GAL) modes is discussed. The structural, morphological, thermal, compositional, and molecular vibration of the prepared CuO/Cu2O nanostructures was characterized by XRD, HRSEM, TG/DTA, FTIR, and EDX techniques. XRD analysis confirmed the crystalline phase of the formation of monoclinic CuO and cubic Cu2O nanostructures with well-defined morphology. The average particle size was found to be 21.52 nm and 26.59 nm for NRs (POT) and NPCs (GAL), respectively, and this result is corroborated from the HRSEM analysis. POT synthesized nanoparticle depicted a higher thermal stability up to 600°C implying that the potentiostatically grown coral-like NRs exhibit a good crystallinity and well-ordered morphology.

Preparation and Magnetic Properties of Carbon Encapsulated Fe-Cu Alloy Nanoparticles

2010 ◽  
Vol 177 ◽  
pp. 673-676 ◽  
Author(s):  
Jun Xue ◽  
Hou Kui Xiang ◽  
Hong Qiao Ding ◽  
Shu Li Pang ◽  
Xue Hua Wang ◽  
...  
Keyword(s):  
Magnetic Measurement ◽  
Average Particle Size ◽  
Soft Magnetic Property ◽  
Copper Nitrate ◽  
Synthesis Process ◽  
Ferric Nitrate ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Alloy

Carbon encapsulated Fe-Cu alloys nanoparticles were synthesized by using ferric nitrate, copper nitrate as metal sources and using sucrose as carbon source. The synthesis process involved a step of hydrazine hydrate reduction in alcohol solution and a step of annealing carbonization. The as-prepared samples were characterized by X-ray diffraction technique, X-ray energy dispersion spectrograph, trans- mission electron microscopy and Raman spectroscopy. The results showed the sample was core / shell structure, the metalic core was crystalline FeCu4 alloy, the shell was amorphous carbon, and the average particle size was about 51nm. The magnetic measurement by using a vibrating sample magnetometer revealed that the sample has ultra-soft magnetic property with the saturation magnetization Ms of 13.01 emu/g, residual magnetization Mr of 0.37 emu/g and coercive forces Hc of 54.43 Oe at room temperature.

Fe3O4 Magnetic Preparation by Bauxite Ore Washing Fine Mud

2014 ◽  
Vol 1010-1012 ◽  
pp. 961-965
Author(s):  
Jian Qiang Xiao ◽  
Guo Wei He ◽  
Yan Jin Hu
Keyword(s):  
Particle Size ◽  
Aging Time ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Test Methods ◽  
Raw Material ◽  
Molar Ratio ◽  
Average Particle ◽  
Experimental Conditions ◽  
Particle Size Analyzer

Bauxite waste sludge as a raw material, the use of reverse chemical coprecipitation synthesize Fe3O4. Researching temperature, precipitation concentration, aging time and Fe2+/Fe3+ molar ratio effect on the particle size, morphology. Optimal experimental conditions: temperature 70 °C, the precipitant NaOH mass ratio of 10%, aging time 3h, Fe2+/Fe3+ molar ratio of 2:3. Test methods using a laser particle size analyzer, XRD analysis of the products were characterized, the product is Fe3O4, the average particle size of 0.11mm.

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