Fabrication of Silica Monoliths with Hierarchically Porous Structure from Freeze-Drying

2015 ◽  
Vol 814 ◽  
pp. 76-80
Author(s):  
Lu Lu ◽  
Yu Lei Wei ◽  
Jie Lin ◽  
Lei Qian
Keyword(s):  
Porous Structure ◽  
Freeze Drying ◽  
Nitrogen Adsorption ◽  
Macroporous Silica ◽  
Silica Monoliths ◽  
Silica Monolith ◽  
Hierarchical Porous ◽  
Mercury Porosimeter ◽  
Adsorption Desorption

This paper provides a novel route to prepare silica monoliths with hierarchical porous structure via freeze drying. In this method, macroporous silica monoliths were first produced by freeze-drying and calcination. By adjusting the concentration of cetyltrimethylammonium bromide in ethylsilicate, a layer of mesoporous thin film was attached on the macroporous silica monolith. The structural characterization of the hierarchical porous monoliths were studied by field emission scanning electron microscopy, mercury porosimeter and nitrogen adsorption-desorption techniques (BET). It turned out that the pore distribution of the obtained monoliths was ranged from 3.72 nm to 23.21nm and the maximum specific surface area calculated from BET was about 288 m2/g, which indicated the existence of hierarchical structure in the obtained material.

scholarly journals Synthesis and Textural Characterization of Mesoporous and Meso-/Macroporous Silica Monoliths Obtained by Spinodal Decomposition

Inorganics ◽  
2016 ◽  
Vol 4 (2) ◽  
pp. 9 ◽  
Author(s):  
Anne Galarneau ◽  
Zakaria Abid ◽  
Bilel Said ◽  
Youcef Didi ◽  
Katarzyna Szymanska ◽  
...  
Keyword(s):  
Spinodal Decomposition ◽  
Macroporous Silica ◽  
Silica Monoliths ◽  
Textural Characterization

Preparation and Characterization of Catalysts Fe/SBA-15 for Fischer Tropsch Synthesis

2014 ◽  
Vol 805 ◽  
pp. 678-683
Author(s):  
Ângela da Costa Nogueira ◽  
Jocielys Jovelino Rodrigues ◽  
Liliane Andrade Lima ◽  
Meiry Glaúcia Freire Rodrigues
Keyword(s):  
Nitrogen Adsorption ◽  
Tropsch Synthesis ◽  
X Ray Diffraction ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
X Ray ◽  
Acidic Conditions ◽  
Diffraction Peaks ◽  
Adsorption Desorption

In this study catalysts Fe/SBA-15 were prepared for Fischer-Tropsch Synthesis. SBA-15 samples were synthesized under acidic conditions using triblock copolymer Pluronic as a template and tetraethyl orthosilicate as a silica source.The molar composition was: 1.0 TEOS: 0017 P123: 8.14 HCl: 168 H2O. Fe/SBA-15 catalysts with different iron loading (15 wt. % and 20 wt. %) were prepared by wetness impregnation of relative SBA-15 with the desired amount of aqueous iron nitrate. The obtained catalyst were characterized by X ray diffraction (XDR), nitrogen adsorption-desorption and energy dispersive X-ray spectrometry (EDX). After impregnation of Fe the XRD profiles were almost unchanged and exhibited the high diffraction peaks of SBA-15 at low angles. The analysis of nitrogen adsorption-desorption was observed that the values of specific surface area decreased as the concentration of metal impregnated increased. And by the EDX analysis verified that the iron contents obtained are close to nominal levels of iron.

scholarly journals Porous Structure and Adsorption Properties of Synthetic Active Carbons

1995 ◽  
Vol 12 (4) ◽  
pp. 267-277 ◽  
Author(s):  
A.M. Puziy ◽  
R. Leboda ◽  
V.I. Bogillo ◽  
V.P. Shkilev ◽  
A. Lodyga
Keyword(s):  
Porous Structure ◽  
Nitrogen Adsorption ◽  
Adsorption Properties ◽  
Active Carbons ◽  
Regularization Technique ◽  
Synthetic Active Carbons ◽  
Nitrogen Adsorption Isotherms ◽  
Bimodal Porous Structure ◽  
Micropore Size

The porous structures of synthetic active carbons have been examined in detail on the basis of nitrogen adsorption isotherms at 77 K using the αS method, the Dubinin–Stoeckli approach and the regularization technique. Analysis of the porosity of synthetic active carbons shows that carbons obtained under identical conditions have dissimilar adsorption properties depending on the size of the granule. The application of the Dubinin–Stoeckli equation for the characterization of strongly heterogeneous carbons overestimates the maximum amount adsorbed in the micropores. In contrast to the Dubinin–Stoeckli equation, the regularization method gives a two-peak micropore size distribution and enables adsorbents with a bimodal porous structure to be estimated.

scholarly journals CTAB-Assisted Hydrothermal Synthesis of WO3Hierarchical Porous Structures and Investigation of Their Sensing Properties

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Dan Meng ◽  
Guosheng Wang ◽  
Xiaoguang San ◽  
Yanbai Shen ◽  
Guodong Zhao ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Nitrogen Adsorption ◽  
Fast Response ◽  
Photoelectron Spectra ◽  
Porous Structures ◽  
X Ray ◽  
Transmission Electron ◽  
Hierarchical Porous ◽  
Adsorption Desorption ◽  
Higher Sensitivity

WO3hierarchical porous structures were successfully synthesized via cetyltrimethylammonium bromide- (CTAB-) assisted hydrothermal method. The structure and morphology were investigated using scanning electron microscope, X-ray diffractometer, transmission electron microscopy, X-ray photoelectron spectra, Brunauer-Emmett-Teller nitrogen adsorption-desorption, and thermogravimetry and differential thermal analysis. The result demonstrated that WO3hierarchical porous structures with an orthorhombic structure were constructed by a number of nanoparticles about 50–100 nm in diameters. The H2gas sensing measurements showed that well-defined WO3hierarchical porous structures with a large specific surface area exhibited the higher sensitivity compared with products without CTAB at all operating temperatures. Moreover, the reversible and fast response to H2gas and good selectivity were obtained. The results indicated that the WO3hierarchical porous structures are promising materials for gas sensors.

Characterization of Activated Carbon from Wood Sawdust Prepared via Chemical Activation Using Potassium Hydroxide

2013 ◽  
Vol 832 ◽  
pp. 132-137 ◽  
Author(s):  
Azry Borhan ◽  
Mohd Faisal Taha ◽  
Athirah Amer Hamzah
Keyword(s):  
Activated Carbon ◽  
Potassium Hydroxide ◽  
Chemical Activation ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Bet Surface Area ◽  
Wood Sawdust ◽  
Activation Conditions ◽  
Adsorption Desorption

The preparation of activated carbon from wood-based industrys residue is one of the most environmental friendly solutions of transforming negative-valued wastes to valuable materials. Wood sawdust was first chemically activated using potassium hydroxide, KOH and characterized by nitrogen adsorption-desorption isotherms measured in Micrometrices ASAP 2020 and Field Emission Scanning Electron Microscope (FESEM). By manipulating three different parameters, the optimal activation conditions were found at temperature of 500°C, activation time of 60 min and impregnation ratio of 1:3. Results showed that the BET surface area, total pore volume and diameter of activated carbon were 1876.16 m2g-1, 0.88 cm3g-1and 6.93 nm, respectively. Nitrogen adsorption desorption isotherm analysis proved the existence of mesopores in activated carbon produced, suggesting that it can be effectively used as an adsorption material.

Synthesis and Characterization of ZrO2/Graphene Nanocomposite Materials

2012 ◽  
Vol 531 ◽  
pp. 161-164 ◽  
Author(s):  
Zong Hua Wang ◽  
Fu Qiang Zhu ◽  
Jan Fei Xia ◽  
Fei Fei Zhang ◽  
Yan Zhi Xia ◽  
...  
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Simple Method ◽  
Transmission Electron ◽  
Ft Ir ◽  
Graphene Nanocomposite ◽  
Adsorption Desorption

Zirconia/graphene (ZrO2/graphene) nanocomposite has been successfully synthesized by a simple method. The as-prepared nanocomposite was characterized using transmission electron microscopy (TEM), FT-IR spectroscopy, power X-ray diffraction (XRD) and nitrogen adsorption-desorption. It was found that tetragonal ZrO2was uniformly deposited on graphene, which resulted in the formation of two-dimensional nanocomposite, it showed a high surface area of 165 m2/g.

Synthesis and Characterization of the Catalysts 5 wt.% and 10 wt.% Co/SBA-15

2010 ◽  
Vol 660-661 ◽  
pp. 561-566
Author(s):  
L.A. Lima ◽  
B.V. Sousa ◽  
Meiry Glaúcia Freire Rodrigues
Keyword(s):  
Ethylene Oxide ◽  
Molecular Sieve ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Poly Ethylene Oxide ◽  
Desorption Isotherms ◽  
Poly Ethylene ◽  
Adsorption Desorption

Catalysts supported on SBA-15 were obtained by wet impregnation using aqueous solution of cobalt nitrate, where different contents of cobalt (5 wt% and 10 wt%) were prepared. The molecular sieve SBA-15 was synthesized using tetra ethyl ortho silicate (TEOS) as silicate source, and triblock copolymer, poly-(ethylene oxide)-poly (propylene oxide)-poly-(ethylene oxide) PEO-PPO-PEO as the organic structure directing agent. These materials were characterized by X-ray diffraction (XRD), X-ray energy dispersion spectrophotometer (EDX) and Nitrogen adsorption–desorption isotherms (BET). The results from the XRD showed that the molecular sieve mesoporous (SBA-15) was identified by X-ray diffraction, especially from the (210) and (300) peaks, which represent a typical spectrum for the SBA-15. Characterization of catalysts by Nitrogen adsorption–desorption isotherms (BET) made it possible to verify the the samples had been of type IV with hysteresis of corresponding the H2 type the porous materials.

Preparation and Characterization of Cobalt Modified Rectorite

2013 ◽  
Vol 773 ◽  
pp. 263-266 ◽  
Author(s):  
Xiao Rong Zhao ◽  
Li Hua Zhu ◽  
He Qing Tang
Keyword(s):  
Nitrogen Adsorption ◽  
Interlayer Spacing ◽  
X Ray Diffraction ◽  
Step Method ◽  
Bet Specific Surface Area ◽  
Pore Properties ◽  
Adsorption Desorption ◽  
Resultant Material

Cobalt modified rectorite (Co@R) was prepared from sodium saturated rectorite (Na-R) with a two-step method of microwave-assisted ion-exchange and in-situ hydrolysis. The morphology, composite structure and pore properties of Co@R were observed with scanning electron microscopy (SEM), small angle X-ray Diffraction (XRD) and nitrogen adsorption-desorption isotherm. The adsorption ability and catalytic behavior of Co@R were studied with methyl blue (MB) as probe contaminant. The interstratified layered Na-R was stripped fully and the resultant material remained the layered structure with a slit-shaped pore between the layers of lamellar particles. The interlayer spacingd001of rectorite was increased successfully from 2.23 nm up to 2.72 nm. The Co@R has a BJH pore volume of 0.091 cm3g-1resulting from the macropores and BET specific surface area of 28.5 m2g-1. A set of test has shown that Co@R possesses the potential to become a good adsorbent and catalyst for activating peroxymonosulfate (PMS), removing organic pollutants efficiently.

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