A cost-effective and fast synthesis of nanoporous SiO2 aerogel powders using water-glass via ambient pressure drying route

Bhagat, Sharad D.; Kim, Yong-Ha; Moon, Mikyeong; Ahn, Young-Soo; Yeo, Jeong-Gu

doi:10.1016/j.solidstatesciences.2007.04.020

Cited by 100 publications

(55 citation statements)

References 25 publications

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“…3(a) we can see that both hydrophobic and hydrophilic silica aerogels exhibit type-IV adsorption isotherms, which indicate the presence of mesopores [17]. The desorption cycles of the isotherms showed a hysteresis loop which is generally attributed to the capillary condensation occurring in the mesopores [18]. In addition, the adsorption isotherms are very similar to that of the supercritically dried aerogels [19].…”

Section: Textural Properties Of Silica Aerogels and Xerogelmentioning

confidence: 87%

Preparation and characterization of a novel silica aerogel as adsorbent for toxic organic compounds

Liu

Sha

Cooper

et al. 2009

Colloids and Surfaces A: Physicochemical and Engineering Aspect

108

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a b s t r a c tHydrophobic and hydrophilic silica aerogels were prepared from cheap waterglass precursors via surface modification of wet gels, ambient pressure drying (APD) route and calcination treatment. Xerogel was also synthesized as a comparison to test the influence of microstructure on the adsorption behaviours. Ethanol (EtOH)/chlorotrimethylsilane (TMCS)/hexane solution was employed to replace the surface silanol groups (Si OH) with alkyl, and to prevent the condensation and shrinkage of the gel structure during the APD process. The synthesized silica aerogels, characterized by using Fourier transform infrared spectra (FTIR), nitrogen adsorption/desorption measurement, element analyses and differential scanning calorimeter (DSC), etc., are porous and translucent solids with surface area of 546-907 m 2 /g. The transition temperature from hydrophobic to hydrophilic was tested around 395 • C, which corresponds to the disappearance temperature of the CH 3 peaks in FTIR. The materials were tested for adsorption capacities on rhodamine B (RhB) and dieldrin, which represented soluble and slightly soluble organic compounds, respectively. Results showed that the hydrophobic silica aerogel exhibited strong adsorption capacity on slightly soluble organic compounds while hydrophilic silica aerogel was much more effective on adsorbing soluble compounds from aqueous solution. Adsorption properties of the silica aerogel remain stable after 5 adsorption/desorption cycles.

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Section: Textural Properties Of Silica Aerogels and Xerogelmentioning

confidence: 87%

Preparation and characterization of a novel silica aerogel as adsorbent for toxic organic compounds

Liu

Sha

Cooper

et al. 2009

Colloids and Surfaces A: Physicochemical and Engineering Aspect

108

View full text Add to dashboard Cite

show abstract

“…In addition, the multilayer adsorption might occur in the middle relative pressure range. The desorption cycle of the isotherm displays a H2 type of the hysteresis loop, which is often associated with a complex mesoporous structure where the distribution of pore size and shape is not well defined [33,34].…”

Section: N 2 Adsorption-desorption Isothermsmentioning

confidence: 99%

Green Synthesis and Characterization of Biosilica Produced from Sugarcane Waste Ash

Alves

Reis

Rovani

et al. 2017

Journal of Chemistry

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In this study, ash from sugarcane waste was used in the synthesis of biosilica using alkaline extraction followed by acid precipitation. Different parameters that could influence the silica particle synthesis were evaluated. The ash and synthesized biosilica were characterized by a combination of spectroscopic and chemical techniques such as XRD, XRF, SEM, particle size analyser, N 2 adsorption analysis, TGA, and FTIR. The best condition for biosilica production was achieved with fusion method and aging temperature of 80 ∘ C for 1 h during gel formation. X-ray powder diffraction pattern confirms the amorphous nature of synthesized silica. The purity of the prepared silica was 99% silica which was confirmed by means of XRF. The experimental data suggest that the sugarcane waste ash could be converted into a value-added product, minimizing the environmental impact of disposal problems.

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“…The physisorption isotherm is of type IV, which is typical of mesoporous materials [28]. The SiO 2 cryogels with X = 11 exhibit an extremely high specific surface area of 1095 m 2 g −1 , and the pore size is distributed in the range of 0.3-35 nm with a high density of micro-and mesopores (0.35-4 nm) as shown in figure 2(b).…”

Section: Microstructurementioning

confidence: 93%

Low-cost and fast synthesis of nanoporous silica cryogels for thermal insulation applications

Liu

Tanaka

et al. 2012

Science and Technology of Advanced Materials

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Nanoporous silica cryogels with a high specific surface area of 1095 m 2 g −1 were fabricated using tert-butyl alcohol as a reaction solvent, via a cost-effective sol-gel process followed by vacuum freeze drying. The total time of cryogel production was reduced markedly to one day. The molar ratio of solvent/precursor, which was varied from 5 to 13, significantly affected the porous structure and thermal insulating properties of the cryogels. The silica cryogels with low densities in the range of 0.08-0.18 g cm −3 and thermal conductivities as low as 6.7 mW (m · K) −1 at 100 Pa and 28.3 mW (m · K) −1 at 10 5 Pa were obtained using this new technique.

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A cost-effective and fast synthesis of nanoporous SiO2 aerogel powders using water-glass via ambient pressure drying route

Cited by 100 publications

References 25 publications

Preparation and characterization of a novel silica aerogel as adsorbent for toxic organic compounds

Preparation and characterization of a novel silica aerogel as adsorbent for toxic organic compounds

Green Synthesis and Characterization of Biosilica Produced from Sugarcane Waste Ash

Low-cost and fast synthesis of nanoporous silica cryogels for thermal insulation applications

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