Preparation and Characterization of Nanoporous Silica Aerogel Granules on The Basis of Water Glass Via Ambient Pressure Drying Method

A crack-free silica aerogel monolith is a nanostructured material with so many surprising properties such as high specific surface area, high porosity, low dielectric constant, low density and outstanding heat insulation properties that were fabricated from a cheap water glass derived silicic acid solution.In this research , the OH surfaces of the wet gel were modified using a HMDZ/n-hexane or TMCS/n-hexane mixture followed by solvent exchange from water to n-hexane. The obtained surface modified wet gel was dried at different temperature under ambient pressure.The properties of hydrophobic silica aerogels synthesized by this new route were investigated by scanning electron microscopy (SEM), differential temperature analysis (DTA) and Fourier-transform infrared spectroscopy (FT-IR).The results showed that 20 wt% HMDZ as surface modifier and 75 °C as drying temperature resulted an acceptable hydrophobic silica aerogel with the density of 0.15 gr/cm³ and specific surface area of about 520 m²/gr.

Download Full-text

Synthesis of high specific surface area silica aerogel from rice husk ash via ambient pressure drying

Colloids and Surfaces A Physicochemical and Engineering Aspects ◽

10.1016/j.colsurfa.2017.12.025 ◽

2018 ◽

Vol 539 ◽

pp. 399-406 ◽

Cited By ~ 21

Author(s):

Qingge Feng ◽

Kao Chen ◽

Dachao Ma ◽

Haiying Lin ◽

Zheng Liu ◽

...

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Rice Husk ◽

Silica Aerogel ◽

Rice Husk Ash ◽

Ambient Pressure ◽

Ambient Pressure Drying ◽

High Specific Surface Area

Download Full-text

Pore Structure Characterization of TiO2-SiO2 Composite Aerogel Prepared via Ambient Pressure Drying by Sol Pre-Modification Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.534.101 ◽

2012 ◽

Vol 534 ◽

pp. 101-105 ◽

Cited By ~ 3

Author(s):

Jing Xiao Liu ◽

Lu Nan Bai ◽

Fei Shi ◽

Zhi Qiang Hu ◽

Yan Yan Jiang ◽

...

Keyword(s):

Specific Surface ◽

Pore Structure ◽

Surface Area ◽

Specific Surface Area ◽

Pore Volume ◽

Ambient Pressure ◽

Volume Ratio ◽

Ambient Pressure Drying ◽

Composite Aerogel ◽

Composite Aerogels

In this paper, TiO2-SiO2composite aerogels were prepared via ambient pressure drying by sol-gel and sol pre-modification method. The pre-modification solution consists of hexamethyldisiloxane (HMDSO) as buffering agent, trimethylchlorosilane (TMCS) as modifier and hexane as organic solvent. The pore structure of TiO2-SiO2composite aerogels was characterized by N2adsorption-desorption method. The effects of HMDSO/TMCS volume ratio on the pore structure and properties of TiO2-SiO2composite aerogel were studied. The results indicate that the pre-modification of TiO2-SiO2composite sol by adding HMDSO/TMCS/Hexane solution could shorten the preparation period. Increasing the amount of HMDSO is favorable for obtaining TiO2-SiO2composite aerogel with higher specific surface area and pore volume. The best volume ratio of HMDSO/TMCS/composite sol for preparing mesoporous TiO2-SiO2composite aerogels were 12:6:120 and 12:12:120, with which the specific surface area and pore volume of the obtained TiO2-SiO2composite aerogel are 425.2～645.4 m2/g and 0.80～2.85 m3/g, respectively.

Download Full-text

Characteristics of carbon aerogel at variation in pyrolysis conditions

Science and Technology Development Journal ◽

10.32508/stdj.v19i3.572 ◽

2016 ◽

Vol 19 (3) ◽

pp. 88-95

Author(s):

Duyen Khac Le ◽

Nghiep Quoc Pham ◽

Kien Anh Le

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Pyrolysis Temperature ◽

Ambient Pressure ◽

Total Pore Volume ◽

Nitrogen Adsorption ◽

Carbon Aerogel ◽

Ambient Pressure Drying ◽

Xrd Diffraction

Carbon aerogel was obtained by pyrolysis of organic aerogel by ambient pressure drying technique. The effect of pyrolysis conditions on characteristics of carbon aerogel such as density, specific surface area and conductivity was studied. The properties and structure of carbon aerogel samples were investigated by nitrogen adsorption, four-point probe method and XRD diffraction. The results showed that carbon aerogel had structure between amorphous and graphite state. The highest specific surface area was 800 m2/g at pyrolysis temperature of 700oC. The pore-size was distributed in microporous, with the maximum total pore volume of 0.44 cm3/g. The electrical conductivity of carbon aerogel was highest at pyrolysis temperature of 800-900oC with the value in the range of 1.744-1.923 S/cm.

Download Full-text

In-situ controlled synthesis of NiFe MOF materials with excellent electrocatalytic performances for water splitting

Functional Materials Letters ◽

10.1142/s1793604721510115 ◽

2021 ◽

Vol 14 (02) ◽

pp. 2151011

Author(s):

Jingwen Jia ◽

Longfu Wei ◽

Ziting Guo ◽

Fang Li ◽

Changlin Yu ◽

...

Keyword(s):

Specific Surface ◽

Surface Area ◽

Water Splitting ◽

Specific Surface Area ◽

High Performance ◽

Alkaline Condition ◽

High Porosity ◽

Large Specific Surface Area ◽

Electrocatalytic Performance

Metal–organic frameworks (MOFs) are the electrocatalytic materials with large specific surface area, high porosity, controllable structure and monodisperse active center, which is a promising candidate for the application of electrochemical energy conversion. However, the electrocatalytic performance of pure MOFs is seriously limited its poor conductivity and stability. In this work, high-performance electrocatalyst was fabricated through combining NiFe/MOF on nickel foam (NF) via in-situ growth strategy. Through rational control of the time and ratio in reaction precursors, we realized the effective manipulation of the growth behavior, and further investigated the electrocatalytic performance in water splitting. The catalyst presented excellent electrocatalytic performance for water splitting, with low overpotential of 260 mV in alkaline condition at a current density of 50 mA[Formula: see text], which is benefited from the large specific surface area and active sites. This study demonstrates that the rational design of NiFe MOF/NF plays a significant role in high-performance electrocatalyst.

Download Full-text

Using Activated Diatomite as Adsorbent for Treatment of Arsenic Contaminated Water

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.850.16 ◽

2020 ◽

Vol 850 ◽

pp. 16-21

Author(s):

Hoc Thang Nguyen ◽

Phong Thanh Dang

Keyword(s):

Specific Surface ◽

Adsorption Capacity ◽

Surface Area ◽

Specific Surface Area ◽

Contaminated Water ◽

Viet Nam ◽

High Porosity ◽

Room Condition ◽

Main Chemical Composition ◽

Adsorbent Capacity

Diatomite or diatomaceous earth (DE) is one of materials which can be used as an adsorbent to treat heavy metal ions from waste water, even there are many factories used it to clean the water for drinking. However, natural DE (raw DE) has very low adsorption capacity because of low specific surface area. In this work, natural DE from Lam Dong province, Viet Nam was demagnetized to remove iron and activated by HCl solution for 90 minutes with concentration of 10% at room condition. Adsorbent capacity was evaluated using As solution and the results show that the activated diatomite has adsorption capacity three times higher than that of raw DE, and the specific surface area of activated diatomite was increased 47.5% with the main chemical composition of 90.8% SiO2 and high porosity

Download Full-text

Manufacture of Fine-Pored Ceramics by the Gelcasting Method

Advances in Materials Science and Engineering ◽

10.1155/2017/5923976 ◽

2017 ◽

Vol 2017 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Bronisław Psiuk ◽

Anna Gerle ◽

Małgorzata Osadnik ◽

Andrzej Śliwa

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Design Theory ◽

Nanoporous Materials ◽

Silica Sol ◽

High Porosity ◽

Simple Method ◽

Fine Grained ◽

Wide Range

The fine-pored materials represent a wide range of applications and searches are being continued to develop methods of their manufacturing. In the article, based on measurements on fine-grained powders of Al2O3, TiO2, and SiO2, it has been demonstrated that gelcasting can be relatively simple method of obtaining of nanoporous materials with high values of both specific surface area and open porosity. The powders were dispersed in silica sol, and the gelling initiator was NH4Cl. The usefulness of experiment design theory for developing of fine-pored materials with high porosity and specific surface area was also shown.

Download Full-text

Relationship between specific surface area and pore dimension of high porosity nanoporous silicon - Model and experiment

physica status solidi (a) ◽

10.1002/pssa.200622237 ◽

2007 ◽

Vol 204 (7) ◽

pp. 2319-2328 ◽

Cited By ~ 15

Author(s):

Monuko du Plessis

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

High Porosity ◽

Nanoporous Silicon ◽

Pore Dimension

Download Full-text

Preparation and Characterization of Ultralow Density Silica Aerogels by Acetonitrile Supercritical Drying

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.519.83 ◽

2012 ◽

Vol 519 ◽

pp. 83-86 ◽

Cited By ~ 6

Author(s):

Guang Wu Liu ◽

Xing Yuan Ni ◽

Bin Zhou ◽

Qiu Jie Yu

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Silica Aerogel ◽

Sol Gel ◽

Supercritical Drying ◽

Silica Aerogels ◽

High Specific Surface Area ◽

Molar Ratio ◽

Sol Gel Process

This paper deals with the synthesis of ultralow density silica aerogels using tetramethyl orthosilicate (TMOS) as the precursor via sol-gel process followed by supercritical drying using acetonitrile solvent extraction. Ultralow density silica aerogels with 6 mg/cc of density was made for the molar ratio by this method. The microstructure and morphology of the ultralow density silica aerogels was characterized by the specific surface area, SBET, SEM, and the pore size distribution techniques. The results show that the ultralow density silica aerogel has the high specific surface area of 812m2/g. Thermal conductivities at desired temperatures were analyzed by the transient plane heat source method. Thermal conductivity coefficients of silica aerogel monoliths changed from 0.024 to 0.043W/ (m K) as temperature increased to 400°C, revealed an excellent heat insulation effect during thermal process.

Download Full-text

Preparation of Electrospun Active Molecular Membrane and Atmospheric Free Radicals Capture

Molecules ◽

10.3390/molecules24173037 ◽

2019 ◽

Vol 24 (17) ◽

pp. 3037 ◽

Cited By ~ 1

Author(s):

Wang ◽

Su ◽

Yu ◽

Li ◽

Ma ◽

...

Keyword(s):

Free Radicals ◽

Impact Strength ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

High Porosity ◽

Large Specific Surface Area ◽

Optimal Parameters ◽

Electrospun Membranes ◽

Reaction Capacity

We load the natural active molecules onto the spin film in an array using electrospinning techniques. The electrospun active molecular membranes we obtain in optimal parameters exhibit excellent capacity for scavenging radical. The reaction capacity of three different membranes for free radicals are shown as follow, glycyrrhizin acid membrane > quercetin membrane > α-mangostin membrane. The prepared active molecular electrospun membranes with a large specific surface area and high porosity could increase the interaction area between active molecules and free radicals. Additionally, it also has improved anti-airflow impact strength, anti-contaminant air molecular interference ability, and the ability to capture free radicals.

Download Full-text