The Microwave-Assisted Preparation and Properties of SiO2 Aerogels by Fractional Modification

2010 ◽  
Vol 148-149 ◽  
pp. 1152-1162 ◽  
Author(s):  
Wen Zhi Zheng ◽  
Li Chen ◽  
Xiang Hua Huang ◽  
Lei Fu
Keyword(s):  
Ambient Pressure ◽  
Sol Gel ◽  
Ambient Pressure Drying ◽  
Base Catalysis ◽  
Raw Material ◽  
Microwave Method ◽  
Scanning Calorimetry ◽  
Hydrophobic Sio2 ◽  
Water Bath Heating ◽  
Fractional Modification

Under microwave radiation and using trimethyl chlorosilane as modifier, hydrophobic SiO2 aerogel was prepared through fractional hydrophobic modification and ambient pressure drying of the raw material, tetraethoxysilane (TEOS), in the process of sol-gel and acid-base catalysis. Hydrophilic SiO2 aerogels were also prepared using the microwave method and water bath heating method. The SiO2 aerogels prepared using the three methods, including their morphology and chemical composition, were analyzed and compared using scanning electron microscopy, Brunauer-Emmett-Teller analysis method, Fourier transform infrared spectroscopy, X-ray diffraction, and themogravimetric-differential scanning calorimetry. The results indicate that by adopting the microwave reaction, the specific surface area of the SiO2 aerogels was effectively increased and the structure of the internal nanoscale pores of petal-coated shape was found to exist under the dense external surface of the SiO2 aerogels. Thermal stability of the hydrophobic SiO2 aerogels prepared through fractional modification assisted by the microwave method was increased with the hydrophobic angle at153°, which showed super hydrophobicity.

Ultrasonic Wave Assisted Preparation and Properties of SiO2 Aerogels by Fractional Modification

2012 ◽  
Vol 557-559 ◽  
pp. 1037-1040
Author(s):  
Wei Ming Yao ◽  
Wen Zhi Zheng ◽  
He Chao Pan ◽  
Zhen Yue Chi ◽  
Hai Jian Chen
Keyword(s):  
Ultrasonic Wave ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Acid Catalyst ◽  
Ambient Pressure Drying ◽  
Pore Distribution ◽  
Base Catalysis ◽  
Raw Material ◽  
Transmission Electron ◽  
20 Nm

In this study, hydrophobic SiO2 aerogel was prepared through fractional hydrophobic modification and ambient pressure drying of the raw material, tetraethoxysilane (TEOS) under ultrasonic wave and using trimethyl chlorosilane as modifier and acid catalyst in the process of sol-gel and acid-base catalysis. SiO2 aerogels were analyzed and compared using scanning electron microscopy (SEM), transmission electron microscope (TEM), Brunauer-Emmett-Teller analysis method, Fourier transform infrared spectroscopy, X-ray diffraction. The results indicate that by adopting the ultrasonic wave, the specific surface area of SiO2 aerogels was 801.71 m2/g. Pore distribution in micro-pore range was 0.5-1 nm. Pore distribution in meso-pore range was 2.0-20 nm. The hydrophobic SiO2 aerogels with the hydrophobic angle at 160° displayed super hydrophobicity.

The Ultrasonic Wave-Assisted Preparation and Modification by KH-550 of SiO2 Aerogels

2012 ◽  
Vol 554-556 ◽  
pp. 580-583 ◽  
Author(s):  
Wen Zhi Zheng ◽  
He Chao Pan ◽  
Zhen Yue Chi ◽  
Hai Jian Chen
Keyword(s):  
Ultrasonic Wave ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Acid Catalyst ◽  
Temperature Tolerance ◽  
Ambient Pressure Drying ◽  
Pore Distribution ◽  
Raw Material ◽  
Analysis Method ◽  
Thermal Stability Of

Under ultrasonic wave and using aminopropyltriethoxysilane as modifier and acid catalyst, hydrophobic SiO2aerogel was prepared through fractional hydrophobic modification and ambient pressure drying of the raw material, tetraethoxysilane (TEOS), in the process of sol-gel and acid-base catalysis.SiO2aerogels were analyzed and compared using scanning electron microscopy, Brunauer-Emmett-Teller analysis method, Fourier transform infrared spectroscopy. The results indicate that modifiering by the ultrasonic wave and aminopropyltriethoxysilane, the temperature tolerance of the SiO2aerogels was 407°C.the specific surface area of the SiO2aerogels was 877.17m2/g. Pore distribution in micro -pore range was 0.5～1nm. Pore distribution in meso -pore range was 1.8～2.5nm. Thermal stability of the hydrophobic SiO2aerogels prepared through fractional modification assisted by the ultrasonic wave method was increased with the hydrophobic angle at160°, which showed super hydrophobicity.

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.

Bioactive and Biocompatible Silica/Pseudowollastonite Aerogels

2014 ◽  
Vol 96 ◽  
pp. 21-26 ◽  
Author(s):  
P.J. Reséndiz-Hernández ◽  
D.A. Cortés-Hernández ◽  
Juan Méndez Nonell ◽  
J.C. Escobedo-Bocardo
Keyword(s):  
Bone Tissue ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Ambient Pressure Drying ◽  
Bone Tissue Regeneration ◽  
Tissue Formation ◽  
Potential Applications ◽  
Ft Ir ◽  
Bone Tissue Formation

Silica aerogels have attracted increasingly more attention due to their extraordinary properties and their existing and potential applications in a wide variety of technological areas. Materials that promote bone-tissue formation at their surface and bond to osseous tissues when implanted are called bioactive, such as pseudowollastonite particles. In this work, the synthesis of aerogels with pseudowollastonite particles was performed. The synthesis involved the preparation of an alcogel by a two step sol-gel route followed by ambient pressure drying. To promote a higher bioactivity the obtained aerogels were then biomimetically treated using simulated body fluids, SBF and 1.5 SBF. A high bioactivity was demonstrated by FT-IR, SEM, EDS, and XRD. The in vitro biocompatibility was assessed by testing cytotoxicity using rat osteoblasts cultures. The results obtained indicate that these materials are highly potential aerogels for bone tissue regeneration.

Synthesis and Characterization of Amine Impregnated Silica Aerogel from Rice Husk for CO2 Adsorption

2020 ◽  
Vol 13 ◽  
Author(s):  
A.R. Hidayu ◽  
N.F. Mohammad ◽  
S.I.S. Jamaludin ◽  
N.F.M.K. Teo ◽  
N.S.M. Sah ◽  
...  
Keyword(s):  
Rice Husk ◽  
Silica Aerogel ◽  
Co2 Adsorption ◽  
Sodium Hydroxide Solution ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Ambient Pressure Drying ◽  
Modified Silica ◽  
Rice Husk Silica ◽  
Wide Range

Abstract: Rice husk has attracted considerable attention in the recent years due to its chemical component that are beneficial to a wide range of application. . In this paper, silica aerogel from rice husk ash (RHA) was prepared through sol-gel processing and ambient pressure drying. The silica RHA was extracted with sodium hydroxide solution to produce sodium silicate solution and neutralized with sulphuric acid to form silica gel. Then, the silica aerogel was further modified with amine, which is 3-(aminopropyl) triethoxysilane (APTES) because amine groups provide specific adsorption sides for CO2 adsorption. The functional group, surface morphology and elemental composition of rice husk, silica aerogel and modified silica aerogel were characterized by Fourier transform infrared spectroscopy (FTIR), Scanning Electronic Microscopy (SEM) and Elemental analyser (EA). For amine modified silica aerogel, it was found that the sample consists of N-H band at a certain peak. FTIR and SEM analysis revealed the synthesized silica aerogel has fibrous morphology and indicates similar trend with previous researches. The amine modified silica aerogel (AMSA) is able to adsorb 0.88 mol CO2/kg AMSA. This study shows that the rice husk silica aerogel modified with APTES could enhance the CO2 adsorption performance due to the physisorption and chemisorption

Preparation of Sodium Silicate–Based Aerogels Using a Two‐Step Sol–Gel Process and Ambient Pressure Drying

2019 ◽  
Vol 387 (1) ◽  
pp. 1800226 ◽  
Author(s):  
Uzma K. H. Bangi ◽  
Shivani S. Pandit ◽  
Dhanashri B. Bagal ◽  
Hyung‐Ho Park
Keyword(s):  
Sodium Silicate ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Ambient Pressure Drying ◽  
Sol Gel Process

A Novel Route for Preparation of Transparent and Superhydrophobic Silica Aerogels

2009 ◽  
Vol 1234 ◽  
Author(s):  
Guo-you Wu ◽  
Xuan Cheng ◽  
Yu-xi Yu ◽  
Ying Zhang
Keyword(s):  
Surface Modification ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Three Dimensional ◽  
Silica Aerogels ◽  
Ambient Pressure Drying ◽  
Nanoporous Structure ◽  
Surface Areas ◽  
Superhydrophobic Silica ◽  
Dta Curve

AbstractSilica aerogels were synthesized via sol-gel processing followed by a two-step surface modification and ambient pressure drying, using methyltrimethoxysilane (MTMS) and trimethylchlorosilane (TMCS)/ethanol/n-hexane as surface modification agents. The transparent silica aerogels possessed the porosities, densities and specific surface areas in the range of 87.7–92.3%, 0.27–0.17 g·cm-3 and 852–1005 m2·g-1, respectively. The SEM and HRTEM analysis revealed the three-dimensional nanoporous structure of the silica aerogels. The presence of –CH3 functional groups on the surface of silica particles as indicated by the FTIR spectra was further confirmed by two visible exothermic peaks at 310 and 450–500 °C from the DTA curve. In addition, the silica aerogels were superhydrophobic with the contact angle as high as 160°.

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.

Study on Preparation of Mesoporous Silica Aerogels with Low Density and High Properties via Ambient Pressure Drying

2010 ◽  
Vol 148-149 ◽  
pp. 1491-1496
Author(s):  
Gang Qiang Geng ◽  
Wei Tao Bi ◽  
Yu Zhang ◽  
Deng Ke Sun
Keyword(s):  
Mesoporous Silica ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Silica Aerogels ◽  
Ambient Pressure Drying ◽  
Ethanol Solution ◽  
Low Density ◽  
Micro Structure ◽  
Gel Time

The SiO2 aerogels of low density was fabricated by ion exchange and sol-gel method on the basis of sodium silicate. The effect of pH, aging，addition of DCCA and annealed temperature on the gel time, aerogel density, porosity and the micro-structure was systemly studied. The results showed that when the pH is 5, aging was 30%Vol .of TEOS/ethanol solution ,the addition of DCCA was 1.5ml, the gel system was annealed at 50 for 84 h, 60 for 72h, the best quality of silica aerogels with low density (0.14g/cm3), higher specific surface(610.643 m2/g) and pore size of 20~40 nm can be obtained.

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.

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