Effects of Preparation Conditions on Characters of Hydrophobic Silica Granular Aerogel and its Applications

2012 ◽  
Vol 600 ◽  
pp. 190-193 ◽  
Author(s):  
Wei Wei ◽  
Jing Yi Zhang ◽  
Li Ping Wu ◽  
Guo Tong Qin
Keyword(s):  
Particle Size ◽  
Ambient Pressure ◽  
High Surface ◽  
Sol Gel ◽  
Average Particle Size ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Ambient Pressure Drying ◽  
Average Particle ◽  
Hydrophobic Silica

The hydrophobic silica granular aerogels were synthesized via sol-gel synthesis followed by ambient pressure drying. The tetraethyloxylane (TEOS) was used as original precursor. The aerogels were analyzed using nitrogen adsorption, scanning electron microscopy (SEM) and laser particle size analyzer. It was found that the aerogel was mesoporous material with high surface area. The aerogels were prepared in grain form by dipping into disperse solution in order to adsorption application. The average particle size of the aerogel was controlled by pH and disperse solution volume. The pH also affected gel time. The aerogels were used to absorb phenol from water. The saturated adsorption amount could reach up to 145 mg•g-1.

A silica aerogel as an extractive coating for in-tube solid-phase microextraction to determine polycyclic aromatic hydrocarbons in water samples

2019 ◽  
Vol 11 (45) ◽  
pp. 5784-5792 ◽  
Author(s):  
Xiangping Ji ◽  
Juanjuan Feng ◽  
Chunying Li ◽  
Sen Han ◽  
Jiaqing Feng ◽  
...  
Keyword(s):  
Silica Aerogel ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Ambient Pressure ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Ambient Pressure Drying ◽  
Acid Base ◽  
Polycyclic Aromatic

A silica aerogel with high surface area was prepared by an acid–base two-step catalytic sol–gel method under ambient pressure drying.

Preparation of monolithic titania aerogels with high surface area by a sol–gel process combined surface modification

RSC Advances ◽  
2014 ◽  
Vol 4 (62) ◽  
pp. 32934-32940 ◽  
Author(s):  
Hui Yang ◽  
Wenjun Zhu ◽  
Sai Sun ◽  
Xingzhong Guo
Keyword(s):  
Surface Modification ◽  
Surface Area ◽  
Ambient Pressure ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Ambient Pressure Drying ◽  
Sol Gel Process

Monolithic titania (TiO2) aerogels with high surface area were successfully synthesized by the sol–gel process combined surface modification, followed by ambient pressure drying.

Comparison of nickel oxide and palladium nanoparticle loaded on activated carbon for efficient removal of methylene blue

2014 ◽  
Vol 34 (2) ◽  
pp. 153-169 ◽  
Author(s):  
S Arabzadeh ◽  
M Ghaedi ◽  
A Ansari ◽  
F Taghizadeh ◽  
M Rajabi
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Particle Size ◽  
Activated Carbon ◽  
Nickel Oxide ◽  
High Surface ◽  
Average Particle Size ◽  
High Surface Area ◽  
Average Particle ◽  
Efficient Removal

Palladium nanoparticles (Pd-NPs) and nickel oxide nanoparticles (NiO-NPs) were synthesized and loaded on activated carbon (AC). This novel material successfully used for the removal of methylene blue (MB) dye from aqueous medium. Full characterization of both material using X-ray diffraction, transmission electron microscopy, scanning electron microscopy and Brunauer–Emmet–Teller analyses for Pd-NP show their high surface area (>1340 m2/g) and low pore size (<20 Å) and average particle size lower than 45 Å and for NiO-NP show their high surface area (>1316.1554 m2/g) and low pore size (<20 Å) and average particle size lower than 46 Å in addition to high reactive atom and presence of various functional groups. These unique properties make them possible for efficient removal of MB. In batch experimental set-up, optimum conditions for maximum removal of MB by both adsorbents were attained following searching effect of variables such as central composite design. The Langmuir isotherm was found to be highly recommended for fitting the experimental equilibrium data. The kinetic of adsorption of MB on both adsorbents strongly can be fitted by a combination of pseudo-second order and intraparticle diffusion pathway. The experimental result achieved in this article shows the superiority of Pd-NP-AC for MB removal than NiO-NP-AC, so the maximum adsorption capacities of Pd-NP-AC and NiO-NP-AC were 555.5 mg/g and 588.2 mg/g, respectively.

scholarly journals Fabrication and characterisation of Fe2O3/chitosan aerogel-like spheres

2021 ◽  
Vol 10 (1) ◽  
pp. 74-78
Author(s):  
Nhan Dang Thi Thanh ◽  
Don Truong Thi ◽  
Thang Le Quoc ◽  
Tien Tran Dong ◽  
Son Le Lam
Keyword(s):  
High Surface ◽  
Sol Gel ◽  
Average Particle Size ◽  
High Surface Area ◽  
Hollow Structure ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Factors Affecting ◽  
Sol Gel Process ◽  
High Surface Area Materials

Presently, biopolymer materials have been given more attention for their outstanding properties, high efficiencies and promising applications in various fields. In this study, Fe2O3/chitosan aerogel-like spheres were successfully prepared from chitosan and FeCl3 by sol–gel process and freeze-drying to provide high-surface area materials. The factors affecting the material synthesis have been studied. The asprepared Fe2O3/chitosan material was characterized by Infrared Spectroscopy (IR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) methods. The results showed that the aerogel spheres have a hollow structure made of chitosan nanofibril networks. Fe2O3 nanoparticles get high crystallinity and have an average particle size of 33 nm.

Hydrophobic Silica Aerogels by Ambient Pressure Drying

2015 ◽  
Vol 830-831 ◽  
pp. 476-479
Author(s):  
Srinivasan Nagapriya ◽  
M.R. Ajith ◽  
H. Sreemoolanadhan ◽  
Mariamma Mathew ◽  
S.C. Sharma
Keyword(s):  
Surface Area ◽  
Atmospheric Pressure ◽  
Polar Solvent ◽  
Ambient Pressure ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Silica Aerogels ◽  
Ambient Pressure Drying ◽  
Sol Gel Process

Silica aerogels have been prepared through sol-gel process by polymerization of TEOS in the presence of NH4F and NH4OH as catalysts. The solvent present in the gel is replaced by ethanol followed by a non-polar solvent such as n-hexane prior to solvent modification step. Gels are made hydrophobic by treating them with HMDZ to prevent rupture during drying, which has been confirmed by FTIR. Gels are then washed and dried carefully in a PID controlled oven at atmospheric pressure. The ageing duration and solvent exchange combinations are optimized to yield crack-free gels prior to drying. Aerogels are characterized for density, specific surface area, pore volume, pore size, thermal stability and contact angle. Hydrophobic, high surface area (570 m2/g), low density (0.07 g/cm3) silica aerogels are synthesized by using optimized mole ratio of precursors and catalysts. Silica aerogel granules (1-3 mm) as well as monoliths (Ф~35 mm) could be produced through ambient pressure drying of gels.

Preparation and Characterization of Aerogel-Based Carbon Nanocomposites

1994 ◽  
Vol 349 ◽  
Author(s):  
Wanqing Cao ◽  
Xian Yun Song ◽  
Arlon J. Hunt
Keyword(s):  
Elevated Temperatures ◽  
High Surface ◽  
Sol Gel ◽  
Average Particle Size ◽  
High Surface Area ◽  
Porous Solids ◽  
Average Particle ◽  
Infrared Transmission ◽  
Hydrocarbon Gases ◽  
Original Weight

ABSTRACTAerogels are highly porous solids prepared by sol-gel processing and supercritical evacuation. Because of their high surface area, aerogels can be used as an effective catalyst for the thermal decomposition of many gaseous compounds. A variety of hydrocarbon gases have been chosen to deposit carbon in the aerogel matrix, with the deposition temperature varying from 500° to 850°C depending on the hydrocarbon used. The amount of carbon that can be deposited in the aerogel is surprisingly large, reaching up to 10 times the original weight after extensive deposition using acetylene. Overall, the aerogel composites prepared have a uniform microstructure with the average particle size in the nanometer range. In addition, we have observed some interesting graphitic structures including carbon nanotubes and rings of various shapes. Carbon deposited in the aerogel can reduce infrared transmission of the material as well as volume shrinkage at elevated temperatures, thereby improving its thermal performance.

scholarly journals High surface area nano-sized La0.6Ca0.4MnO3 perovskite powder prepared by low temperature pyrolysis of a modified citrate gel

2009 ◽  
Vol 7 (4) ◽  
pp. 809-817 ◽  
Author(s):  
Meysam Soleymani ◽  
Ahmad Moheb ◽  
Ezatolah Joudaki
Keyword(s):  
Particle Size ◽  
Surface Area ◽  
Single Phase ◽  
High Surface ◽  
Average Particle Size ◽  
High Surface Area ◽  
Average Particle ◽  
Precursor Method ◽  
Modified Method ◽  
Low Temperature Pyrolysis

AbstractSingle phase nanocrystalline La0.6Ca0.4MnO3 powder was synthesized by both the usual and a modified citrate gel precursor method, and the effects on the formation of homogeneous nano-sized powder with a perovskite structure were investigated. In the modified method, single phase La0.6Ca0.4MnO3 powder with an average particle size of 17.2 nm was obtained when the powder was pyrolyzed at 520°C for 2 h. Its specific surface area was 40.7 m2 g−1, about 4-fold larger than that of powder made by the usual citrate gel method.

Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Bioactive Glasses ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

Preparation of Magnesium-Based Cobalt-Ferrites (Co1−xMgxFe2O4) Nanoparticles by Sol–Gel Auto Combustion Method

2017 ◽  
Vol 17 (01n02) ◽  
pp. 1760012
Author(s):  
S. Gowreesan ◽  
A. Ruban Kumar
Keyword(s):  
Particle Size ◽  
Structural Parameters ◽  
Sol Gel ◽  
Average Particle Size ◽  
Combustion Method ◽  
Dielectric Behavior ◽  
Powder Xrd ◽  
Average Particle ◽  
Cobalt Ferrites ◽  
Auto Combustion

The scope of the present work is in enhancing the particle size, and dielectric properties of Mg-substituted Cobalt ferrites nanoparticles prepared by sol–gel auto combustion method. The different ratios of Mg-substituted Co Ferrites (Co[Formula: see text]MgxFe2O4([Formula: see text], 0.05, 0.10, 0.15, 0.20 and 0.30)) are calcinated at 850[Formula: see text]C. The synthesized nanoparticles were characterized by powder XRD, FTIR, FE-SEM, EDX techniques and dielectric behavior. The structural parameters were confirmed from powder XRD and the average particle size is obtained from 39 to 67 nm due to the substitution of Mg[Formula: see text] which was calculated by Debye Scherrer’s formula. FE-SEM showed the surface morphology of the different ratio of the sample. The dielectric loss has measured the frequency range of 50[Formula: see text]Hz–5[Formula: see text]MHz. From electrical modulus, conductivity relaxation and thermal activation of charge carriers has been discussed.

Fabrication and Microstructure of ZnO-TiO2 Composite Membranes by a Reverse Micelle and Sol-Gel Processing

2006 ◽  
Vol 510-511 ◽  
pp. 786-789 ◽  
Author(s):  
Dong Sik Bae ◽  
Byung Ik Kim ◽  
Kyong Sop Han
Keyword(s):  
Particle Size ◽  
Reverse Micelle ◽  
Porous Alumina ◽  
Sol Gel ◽  
Average Particle Size ◽  
Composite Membranes ◽  
Dip Coating ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Alumina Support

ZnO-TiO2 nanoparticles were synthesized by a reverse micelle and sol-gel process. The average particle size of the colloid was below 30 nm and well dispersed in the solution. ZnOTiO2 composite membranes were fabricated by using the dip-coating method on a porous alumina support. ZnO-TiO2 composite membranes showed a crack-free microstructure and narrow particle size distribution even after the heat treatment up to 600°C. The average particle size of the membrane was 30-40nm, and the pore size of ZnO-TiO2 composite membrane was below 10 nm.

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