Preparation of Porous Silica Microspheres by Polymerization-Induced Colloid Aggregation Method

2014 ◽  
Vol 898 ◽  
pp. 132-135 ◽  
Author(s):  
Jia Li He ◽  
Xiu Hua Chen ◽  
Wen Jie Zhu ◽  
Wen Hui Ma ◽  
Yong Yin Xiao ◽  
...  
Keyword(s):  
Average Pore Size ◽  
Urea Formaldehyde ◽  
Porous Silica ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Bet Surface Area ◽  
Silica Microspheres ◽  
Average Pore ◽  
Uf Resin ◽  
Adsorption Desorption

The UF resin/SiO2 composites microspheres with particle size of 2μm were successfully prepared by polymerization of silica sol from base-catalyzed hydrolysis of tetraethyl orthosilicate, and urea-formaldehyde via the PICA approach, and then calcination in air to remove organic UF resin and yield porous silica microspheres. The samples were characterized by Zetasizer NanoZS Instrument, SEM and Nitrogen adsorption-desorption isotherms. The results showed that the synthesized porous silica microspheres with a BET surface area of 67.01m2/g, a BJH average pore size diameter of 37.32 nm and a total pore volume of 0.69cm3/g, respectively.

Synthesis of Mesoporous Silica Microspheres by PICA and Pseudomorphic Transformation Using Silica Fume as Silica Source

2014 ◽  
Vol 809-810 ◽  
pp. 207-212
Author(s):  
Jia Li He ◽  
Xiu Hua Chen ◽  
Wen Jie Zhu ◽  
Wen Hui Ma ◽  
Yong Yin Xiao ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Silica Fume ◽  
Average Pore Size ◽  
Sorption Isotherms ◽  
Total Pore Volume ◽  
Bet Surface Area ◽  
Silica Microspheres ◽  
Average Pore ◽  
Silica Source ◽  
Mesoporous Silica Microspheres

Monodisperse mesoporous silica microspheres (MSM-SF) were successfully prepared through PICA and pseudomorphic transformation using silica fume as original silica source. The structure and morphology of spheres were quantitatively investigated by Zata potential and particle size analyzer, N2 sorption isotherms, XRD, SEM and TEM. The results showed that the monodisperse spherical mesoporous silica microspheres (MSM-SF) exhibited uniform spherical morphology, worm-like mesoporous, large BET surface area of 559.9m2/g; its BJH average pore size diameter and total pore volume are 3.3nm and 0.12cm3/g, respectively. This preparation method provides a new synthetic strategy to control the particle morphology and structure simultaneously, meanwhile this method can also significantly reduce the cost of synthesis of mesoporous silica microspheres.

scholarly journals Preparation of High-Performance Activated Carbon from Coffee Grounds after Extraction of Bio-Oil

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 257
Author(s):  
Jie Ren ◽  
Nanwei Chen ◽  
Li Wan ◽  
Guojian Li ◽  
Tao Chen ◽  
...  
Keyword(s):  
Activated Carbon ◽  
High Performance ◽  
Average Pore Size ◽  
Total Pore Volume ◽  
Micropore Volume ◽  
Bet Surface Area ◽  
Average Pore ◽  
Activation Temperature ◽  
Coffee Grounds ◽  
Bio Oil

In this study, a new method for economical utilization of coffee grounds was developed and tested. The resulting materials were characterized by proximate and elemental analyses, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and N2 adsorption–desorption at 77 K. The experimental data show bio-oil yields reaching 42.3%. The optimal activated carbon was obtained under vacuum pyrolysis self-activation at an operating temperature of 450 °C, an activation temperature of 600 °C, an activation time of 30 min, and an impregnation ratio with phosphoric acid of 150 wt.%. Under these conditions, the yield of activated carbon reached 27.4% with a BET surface area of 1420 m2·g−1, an average pore size of 2.1 nm, a total pore volume of 0.747 cm3·g−1, and a t-Plot micropore volume of 0.428 cm3·g−1. In addition, the surface of activated carbon looked relatively rough, containing mesopores and micropores with large amounts of corrosion pits.

Preparation and Characterization of Porous Silica Obtained by Hydrochloric Acid Selective Leaching Metakaolinite

2008 ◽  
Vol 368-372 ◽  
pp. 342-344
Author(s):  
Lin Jiang Wang ◽  
Xiang Li Xie
Keyword(s):  
Hydrochloric Acid ◽  
Layered Structure ◽  
Layer Structure ◽  
Average Pore Size ◽  
Porous Silica ◽  
Total Pore Volume ◽  
Selective Leaching ◽  
Average Pore ◽  
Hcl Solution

Porous silica was prepared by selective leaching of metakaolinite with 20 mass% HCl solution. The metakaolinite was derived from the 1:1 layered structure clay mineral kaolinite by firing at 600°C for 24 h. The characteristics of porous silica were studied. The content of Al2O3 in metakaolinite was sharply changed from 45% to less than 2% after 2 h leaching. The maximum specific surface area of the leached sample was about 350 m2/g. The average pore size is about 2 nm. The total pore volume is 0.3 ml/g. The layer structure of kaolinite and metakaolinite is responsible for forming micropores.

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.

scholarly journals Synthesis and photocatalytic performance of spongy ZnO microstructures

2015 ◽  
Vol 33 (2) ◽  
pp. 230-236 ◽  
Author(s):  
Y.L. Zou ◽  
Y. Li ◽  
Q. Wang ◽  
D.M. An ◽  
X.X. Lian ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Raw Materials ◽  
Average Pore Size ◽  
Nitrogen Adsorption ◽  
Bet Surface Area ◽  
Nitrate Hexahydrate ◽  
Average Pore ◽  
Tem Analysis ◽  
Hydrothermal Temperature

AbstractSpongy ZnO microstructures were synthesized via a facile hydrothermal method using zinc nitrate hexahydrate and oxalic acid as raw materials. The as-obtained ZnO were characterized by powder X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), and transmission electron spectroscopy (TEM), respectively. The BET surface area and average pore size of the samples were determined by nitrogen adsorption-desorption analysis. Effects of precursor and hydrothermal temperature on the morphology and photocatalytic activity of the products were investigated. SEM and TEM analysis indicated that the as-obtained spongy ZnO microstructures consisted of a large amount of ZnO particles with the average size of about 100 to 150 nm. The photocatalytic activities of the spongy ZnO microstructures were evaluated by photodegradation of methylene blue (MB) under UV light radiation. The results indicated that the ZnO synthesized at 150 °C for 10 h showed the highest photocatalytic activity and the degradation ratio of MB reached 99.5 % for 60 min of UV light irradiation with the light intensity of 10 mW · cm-2.

scholarly journals Fractal Characteristics and Heterogeneity of the Nanopore Structure of Marine Shale in Southern North China

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 242 ◽  
Author(s):  
Yu ◽  
Ju ◽  
Qi ◽  
Qiao ◽  
Huang ◽  
...  
Keyword(s):  
Pore Volume ◽  
North China ◽  
Average Pore Size ◽  
Fractal Dimensions ◽  
Total Pore Volume ◽  
Integrated Approach ◽  
Bet Surface Area ◽  
Average Pore ◽  
Marine Shale ◽  
Nanopore Structure

The characteristics of the nanopore structure in shale play a crucial role in methane adsorption and in determining the occurrence and migration of shale gas. In this study, using an integrated approach of X-ray diffraction (XRD), N2 adsorption, and field emission scanning electron microscopy (FE-SEM), we systematically focused on eight drilling samples of marine Taiyuan shale from well ZK1 in southern North China to study the characteristics and heterogeneity of their nanopore structure. The results indicated that different sedimentary environments may control the precipitation of clay and quartz between transitional shale and marine shale, leading to different organic matter (OM)–clay relationships and different correlations between total organic carbon (TOC) and mineral content. The shale with high TOC content tended to have more heterogeneous micropores, leading to a higher fractal dimension and a more complex nanopore structure. With the increase of TOC content and thermal evolution of OM, the heterogeneity of the pore structure became more significant. Quartz from marine shale possessed abundant macropores, resulting in a decrease of the Brunauere–Emmette–Teller (BET (BET) surface area (SA) and an increase of the average pore size (APS), while clay minerals developed a large number of micropores which worked together with OM to influence the nanopore structure of shale, leading to the increase of the SA and the decrease of the APS. The spatial order of interlayer pores increased with the increase of mixed-layer illite–smectite (MLIS) content, which naturally reduced the fractal dimensions. In contrast, kaolinite, chlorite, and illite have a small number of nanopores, which might enhance the complexity and reduce the connectivity of the nanopore system by mean of pore-blocking. Taiyuan shale with higher heterogeneity is highly fractal, and its fractal dimensions are principally related to the micropores. The fractal dimensions correlate positively with the SA and total pore volume, suggesting that marine shale with higher heterogeneity may possess a larger SA and a higher total pore volume.

scholarly journals One-Pot Synthesis and Characterization of VO2(B) with a Large Voltage Window Electrochemical Performance in Aqueous Solution

2020 ◽  
Vol 10 (8) ◽  
pp. 2742
Author(s):  
Xiaoyu Liu ◽  
Jiqi Zheng ◽  
Xuyang Jing ◽  
Yan Cheng ◽  
Changgong Meng
Keyword(s):  
Vanadium Dioxide ◽  
Average Pore Size ◽  
Bet Surface Area ◽  
Porous Structures ◽  
One Pot ◽  
Average Pore ◽  
Discharge Current Density ◽  
One Step ◽  
Adsorption Desorption

B-type vanadium dioxide (defined as VO2(B)) nanobelts were synthesized through using commercial ammonium metavanadate, oxalic acid via one-step hydrothermal technique. The structure of VO2(B) was characterized using different instruments. N2 adsorption-desorption isotherms revealed that the VO2(B) nanobelts were porous structures where BET surface area was 10.4 m2·g−1, the pore volume was 0.0687 cm3/g, and the average pore size was 42.7 nm. Furthermore, the VO2(B) nanobelts as supercapacitors electrode exhibited a large voltage window (−0.8~1.0 V). The measured capacitance was based on the pseudocapacitance. When the discharge current density is 0.5, 1, and 10 A·g−1, the VO2(B) shows the specific capacitance of 287, 246, and 222 F·g−1, respectively.

Sol-Gel Derived Silica Layers for Low-k Dielectrics Applications

2000 ◽  
Vol 612 ◽  
Author(s):  
Sylvie Acosta ◽  
André Ayral ◽  
Christian Guizard ◽  
Charles Lecornec ◽  
Gérard Passemard ◽  
...  
Keyword(s):  
Average Pore Size ◽  
Sol Gel ◽  
Porous Silica ◽  
Thin Layers ◽  
Gaseous Ammonia ◽  
Potential Candidate ◽  
Average Pore ◽  
Synthesis Strategy ◽  
Silica Layers ◽  
Highly Porous

AbstractPorous silica exhibits attractive dielectric properties, which make it a potential candidate for use as insulator into interconnect structures. A new way of preparation of highly porous silica layers by the sol-gel route was investigated and is presented. The synthesis strategy was based on the use of common and low toxicity reagents and on the development of a simple process without gaseous ammonia post-treatment or supercritical drying step. Defect free layers were deposited by spin coating on 200 mm silicon wafers and characterized. Thin layers with a total porosity larger than 70% and an average pore size of 5 nm were produced. The dielectric constant measured under nitrogen flow on these highly porous layers is equal to ∼ 2.5, which can be compared to the value calculated from the measured porosity, ∼ 1.9. This difference is explained by the presence of water adsorbed on the hydrophilic surface of the unmodified silica.

Optimization of Production Conditions for Activated Carbons from Rice Husk by Potassium Carbonate Using Response Surface Methodology

2014 ◽  
Vol 1053 ◽  
pp. 303-310 ◽  
Author(s):  
Mian Wu Meng ◽  
Cong Liang Qi ◽  
Qing Ye Liu ◽  
Liang Lv ◽  
Hao Ai ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Adsorption Capacity ◽  
Response Surface ◽  
Rice Husk ◽  
Activated Carbons ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Average Pore ◽  
Activation Temperature ◽  
Nitrogen Adsorption Isotherm

A three-factor-three-level experiment was developed by the central composite design (CCD) and Response surface methodology to discuss the effects of concentration of K2CO3, activation temperature and time on the adsorption capacity of the activated carbon (AC) derived from the rice husk and to identify the key preparation parameters. The performance of the AC was characterized by nitrogen adsorption isotherm as Brunauer–Emmett–Teller (BET) and scanning electron microscope (SEM), respectively. The optimal parameters were obtained: Rice husk was soaked in K2CO3 solution (2.32 mol/L) with an impregnation ratio (rice husk: K2CO3=1:3) (wt. %), activated at 1239 K for 0.48 h. The results showed that iodine adsorption capacity of the AC was 1268.52 mg/g, the error between the models predicted (1356.98 mg/g) was only 6.2%. The AC has a large apparent surface area (SBET = 1312 m2/g), total pore volume (0.78 cm3/g) and average pore diameter (11.92 Å).

Preparation and Characterization of Fe2O3/ SBA-15 for Fischer-Tropsch Process

2020 ◽  
Vol 850 ◽  
pp. 144-150
Author(s):  
Agija Stanke ◽  
Valdis Kampars ◽  
Oana A. Lazar ◽  
Marius Enachescu
Keyword(s):  
Average Pore Size ◽  
Direct Synthesis ◽  
Synthesis Method ◽  
Xrd Analysis ◽  
Hexagonal Structure ◽  
Catalyst Characterization ◽  
Average Pore ◽  
Pluronic P123 ◽  
Silica Source ◽  
Adsorption Desorption

In this study Fe2O3/SBA-15 catalyst was synthesized via direct synthesis method under acidic conditions using triblock copolymer Pluronic P123 as template, tetraethyl orthosilicate as a silica source and Fe (NO3)3∙9H2O as iron source. Template was removed using extraction and calcination. The obtained catalyst was characterized using XRD analysis, WDXRF spectroscopy, N2 adsorption-desorption analysis and STEM–EDX measurements. Results of catalyst characterization showed that the synthesized Fe2O3/SBA-15 is mesoporous silica with 2D p6mm hexagonal mesostructure loaded with 15.6 wt.% Fe2O3. Average pore size was 6.95 nm, homogeneous immobilized Fe2O3 nanoparticles do not disrupt the porous hexagonal structure of the support.

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