Study on Porous Structure and Surface Characteristics of Al-Pillared Montmorillonite

2011 ◽  
Vol 194-196 ◽  
pp. 1834-1838 ◽  
Author(s):  
Gui Fang Wang ◽  
Shao Jian Ma ◽  
Shuai Zhang ◽  
Xian Jun Lu ◽  
Wei Mo ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Surface Characteristics ◽  
Interlayer Spacing ◽  
Elemental Distribution ◽  
Volume Distribution ◽  
Pillared Montmorillonite ◽  
Pillaring Solution

Al-pillared montmorillonite (Al-PILM) prepared with Keggin ions was studied by means of XRD, SEM-EDS and N2 adsorption-desorption isotherms.The rusults show that, compared to unpillared Na-montmorillonite (Na-M), the interlayer spacing d(001) value, BET specific surface area, surface fractal dimension and the proportion of microporous specific surface area of Al-PILM are larger and the surface is relatively rough. The BJH porous volume distribution of Al-PILM is the most probable distribution, and the most probable pore size is about 2 nm, belonging to mesopore. The porous structure of Al-PILM is characterized as parallel plate slit or “house-of-cards” wedge-shaped pore which is formed by novel meso-microporous delaminated structure and fragments. Besides, the results of elemental distribution show that the ions exchange action between Na+ and hydroxy-Al cations in pillaring solution occurs in the formation of Al-PILM.

Study on Microstructure Variation Laws of Al-Pillared Montmorillonite

2010 ◽  
Vol 158 ◽  
pp. 248-255 ◽  
Author(s):  
Gui Fang Wang ◽  
Xian Jun Lu ◽  
Shuai Zhang ◽  
Shao Jian Ma ◽  
Jun Qiu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Pore Size ◽  
Surface Area ◽  
Specific Surface Area ◽  
Interlayer Spacing ◽  
Volume Distribution ◽  
Pillared Montmorillonite ◽  
Bet Specific Surface Area ◽  
Pore Size Analysis ◽  
Porous Volume

Al3+/clay ratio is one of the important factors influencing microstructure of Al-pillared montmorillonite. Microstructure variation laws of Al-pillared montmorillonite prepared under the condition of different Al3+/clay ratio are systematically studied by XRD, FTIR, specific surface area and pore size analysis. The results show that the interlayer spacing and BET specific surface area of Al-pillared montmorillonite are remarkably affected by the Al3+/clay ratio. The interlayer spacing d(001) value and BET specific surface area of Al-pillared montmorillonite increase firstly and then decrease with the increases of the Al3+/clay ratio, and they reach to maximum when the Al3+/clay ratio is 10mmol/g. Besides, the BJH porous volume distribution of Al-pillared montmorillonite is the most probable distribution, and the most probable pore size is about 2 nm, which is attributed to mesopore. The porous structure of hydroxy-Al pillared montmorillonite is characterized as parallel plate slit or “house-of-cards” wedge-shaped pore which is formed by novel meso-microporous delaminated structure and fragments. With the increase of the Al3+/clay ratio, BJH total porous volume and mesoporous volume of hydroxy-Al pillared montmorillonite decreases, while the proportion of microporous volume in the total porous volume increases. The proportion of microporous specific surface area of all the hydroxy-Al pillared montmorillonite samples is about 62% and is much larger than that of Na-M and those of mesopore and macropore, indicating the main action of intercalation of hydroxy-Al pillaring solution into montmorillonite interlayer is to increase the micropore amount.

scholarly journals High MB Solution Degradation Efficiency of FeSiBZr Amorphous Ribbon with Surface Tunnels

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3694 ◽  
Author(s):  
Qi Chen ◽  
Zhicheng Yan ◽  
Hao Zhang ◽  
Lai-Chang Zhang ◽  
Haijian Ma ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Free Volume ◽  
Specific Surface Area ◽  
Degradation Rate ◽  
High Efficiency ◽  
Amorphous Ribbon ◽  
Degradation Efficiency ◽  
Characteristic Distance

The as spun amorphous (Fe78Si9B13)99.5Zr0.5 (Zr0.5) and (Fe78Si9B13)99Zr1 (Zr1) ribbons having a Fenton-like reaction are proved to bear a good degradation performance in organic dye wastewater treatment for the first time by evaluating their degradation efficiency in methylene blue (MB) solution. Compared to the widely studied (Fe78Si9B13)100Zr0 (Zr0) amorphous ribbon for degradation, with increasing cZr (Zr atomic content), the as-spun Zr0, Zr0.5 and Zr1 amorphous ribbons have gradually increased degradation rate of MB solution. According to δc (characteristic distance) of as-spun Zr0, Zr0.5 and Zr1 ribbons, the free volume in Zr1 ribbon is higher Zr0 and Zr0.5 ribbons. In the reaction process, the Zr1 ribbon surface formed the 3D nano-porous structure with specific surface area higher than the cotton floc structure formed by Zr0 ribbon and coarse porous structure formed by Zr0.5 ribbon. The Zr1 ribbon’s high free volume and high specific surface area make its degradation rate of MB solution higher than that of Zr0 and Zr0.5 ribbons. This work not only provides a new method to remedying the organic dyes wastewater with high efficiency and low-cost, but also improves an application prospect of Fe-based glassy alloys.

Fabrication of an N-doped mesoporous bio-carbon electrocatalyst efficient in Zn–air batteries by an in situ gas-foaming strategy

2019 ◽  
Vol 55 (100) ◽  
pp. 15117-15120 ◽  
Author(s):  
Hong Wang ◽  
Wei Li ◽  
Zhiwei Zhu ◽  
Yijuan Wang ◽  
Pan Li ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrocatalytic Activity ◽  
High Specific Surface Area ◽  
Carbon Catalyst ◽  
Gas Foaming

An N-doped bio-carbon catalyst with a hierarchical interconnected macro/meso-porous structure and high specific surface area exhibited significantly enhanced electrocatalytic activity.

Preparation, characterization and catalytic properties of yttrium-zirconium-pillared montmorillonite and their application in supported Ce catalysts

Clay Minerals ◽  
2015 ◽  
Vol 50 (2) ◽  
pp. 211-219 ◽  
Author(s):  
Bo Xue ◽  
Hongmei Guo ◽  
Lujie Liu ◽  
Min Chen
Keyword(s):  
Catalytic Activity ◽  
Ethyl Acetate ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Industrial Applications ◽  
High Catalytic Activity ◽  
Total Oxidation ◽  
Pillared Montmorillonite

AbstractA new yttrium-zirconium-pillared montmorillonite (Y-Zr-MMT), was synthesized, characterized and used as a Ce catalyst support. The Y-Zr-MMT is a good support for dispersing cerium active sites and it is responsible for the high activity in the total oxidation of acetone, toluene and ethyl acetate. The Y-Zr-MMT shows greater advantages than the conventional alumina/cordierite honeycomb supports such as large specific surface area, lower cost and easier preparation. Catalytic tests demonstrated that Ce/Y-Zr-MMT (Ce loading 8.0%) was the most active, with the total oxidation of acetone, toluene and ethyl acetate being achieved at 220, 300 and 220°C, respectively. The catalyst displayed better activity for the oxidation of acetone and ethyl acetate than a conventional, supported Pd-catalyst under similar conditions. The special structure of the yttrium-doped zirconium-pillared montmorillonite can strengthen the interaction between the CeO2 and Zr-MMT support and improve the dispersion of the Ce particles, which enhances the catalytic activity for the oxidation of VOCs. The new catalyst, 8.0%Ce/Y-Zr-MMT, could be promising for industrial applications due to its high catalytic activity and low cost. The support and the catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and BET specific surface area measurements.

Effect of aging and alkali activator on the porous structure of a geopolymer

2014 ◽  
Vol 47 (1) ◽  
pp. 316-324 ◽  
Author(s):  
Prune Steins ◽  
Arnaud Poulesquen ◽  
Fabien Frizon ◽  
Olivier Diat ◽  
Jacques Jestin ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Inorganic Polymers ◽  
Porous Network ◽  
X Ray ◽  
Alkali Activator ◽  
Effects Of Aging

Nitrogen sorption and small- and wide-angle X-ray and neutron scattering techniques were used to study the porous structure of geopolymers, inorganic polymers synthesized by reaction of a strongly alkaline solution and an aluminosilicate source (metakaolin). The effects of aging and the use of alkali activators (Na+, K+) of different sizes were investigated at room temperature. The influence of aging time on the microstructure of both geopolymer matrixes was verified in terms of pore volume and specific surface area. The results suggested a refinement of the porosity and therefore a reduction in the pore volume over time. Regardless of the age considered, some characteristics of the porous network such as pore size, shape and distribution depend on the alkali activator used. Whatever the technique considered, the potassium geopolymer has a greater specific surface area than the sodium geopolymer. According to the scattering results, the refinement of the porosity can be associated with, first, a densification of the solid network and, secondly, a partial closure of the porosity at the nanometre scale. The kinetics are much slower for the sodium geopolymer than for the potassium geopolymer in the six months of observation.

scholarly journals Preparation and Application of 2D MXene-Based Gas Sensors: A Review

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 225
Author(s):  
Qingting Li ◽  
Yanqiong Li ◽  
Wen Zeng
Keyword(s):  
Composite Materials ◽  
Specific Surface ◽  
Surface Area ◽  
Gas Sensor ◽  
Specific Surface Area ◽  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
Interlayer Spacing ◽  
Preparation Methods

Since MXene (a two-dimensional material) was discovered in 2011, it has been favored in all aspects due to its rich surface functional groups, large specific surface area, high conductivity, large porosity, rich organic bonds, and high hydrophilicity. In this paper, the preparation of MXene is introduced first. HF etching was the first etching method for MXene; however, HF is corrosive, resulting in the development of the in situ HF method (fluoride + HCl). Due to the harmful effects of fluorine terminal on the performance of MXene, a fluorine-free preparation method was developed. The increase in interlayer spacing brought about by adding an intercalator can affect MXene’s performance. The usual preparation methods render MXene inevitably agglomerate and the resulting yields are insufficient. Many new preparation methods were researched in order to solve the problems of agglomeration and yield. Secondly, the application of MXene-based materials in gas sensors was discussed. MXene is often regarded as a flexible gas sensor, and the detection of ppb-level acetone at room temperature was observed for the first time. After the formation of composite materials, the increasing interlayer spacing and the specific surface area increased the number of active sites of gas adsorption and the gas sensitivity performance improved. Moreover, this paper discusses the gas-sensing mechanism of MXene. The gas-sensing mechanism of metallic MXene is affected by the expansion of the lamellae and will be doped with H2O and oxygen during the etching process in order to become a p-type semiconductor. A p-n heterojunction and a Schottky barrier forms due to combinations with other semiconductors; thus, the gas sensitivities of composite materials are regulated and controlled by them. Although there are only several reports on the application of MXene materials to gas sensors, MXene and its composite materials are expected to become materials that can effectively detect gases at room temperature, especially for the detection of NH3 and VOC gas. Finally, the challenges and opportunities of MXene as a gas sensor are discussed.

scholarly journals SYNTHESIS AND CHARACTERIZATION OF PHOTOCATALYS Fe2O3 PILLARED MONTMORILLONITE DOPED TiO2 AND ITS APPLICATION FOR RHODAMINE B PHODODEGRADATION USING VISIBLE LIGHT IRRADIATION

Jurnal Kimia ◽  
2020 ◽  
pp. 82
Author(s):  
D. A. D. N. Dewi ◽  
I N. Simpen ◽  
I W. Suarsa
Keyword(s):  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Rhodamine B ◽  
High Specific Surface Area ◽  
Montmorillonite Clay ◽  
Pillared Montmorillonite ◽  
Bet Method ◽  
Acid And Base

A montmorillonite clay modified with semiconductor metal can act as a photocatalyst material. Montmorillonite clays were chosen because of their natural characteristics which are easily to be modified and have high specific surface area. This research aims to modify montmorillonite clay into photocatalyst material. The montmorillonite clay was intercalated using Fe2O3 to produce Fe2O3-pillared montmorillonite clay, then doped with TiO2 to form a photocatalyst material Fe2O3-PILC / TiO2. Modifications were intended to increase the specific surface area and number of active photocatalyst sites and thus increase the ability of photodegradation. The characterization carried out included characterizing the pillar formation using X-ray Diffraction (XRD), specific surface area by the BET method (Bruneau, Emmet, and Teller), a the number of surface acid-base sites by the titration method. Photocatalyst with the best character was Fe2O3-PILC / TiO2 1: 3 with specific surface area, number of acid and base sites respectively 45,947 m2/g, 20,1736 x 1023 sites/gram and 19,0044 x 1023 sites/gram. The result of photodegradation at optimum condition with visible light at pH 3 using 400 mg photocatalyst was 99.84%.   Keywords: photocatalyst, Fe2O3, montmorillonite clay, TiO2, rhodamine B

Micro/Nanostructured α-Fe2O3 with Structural Enhanced Removal Capacity of Cr(VI) Ions

2012 ◽  
Vol 518-523 ◽  
pp. 1753-1756 ◽  
Author(s):  
Gang Liu ◽  
Quan Deng ◽  
Yong Yang ◽  
Hui Min Wang ◽  
Guo Zhong Wang
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Average Diameter ◽  
High Specific Surface Area ◽  
Removal Capacity

We have succeeded in preparing micro/nanostructured α-Fe2O3 spheres (MNFSs). The resulted MNFSs have an average diameter of about 5 µm, and are constructed by subunits of interlinked and elongated particles with a diameter of 20~60 nm. MNFSs show an obviously structural enhanced Cr(VI) removal capacity (5.88 mg/g) compared with nanoscaled (0.81 mg/g) and microscaled α-Fe2O3 (0.1 mg/g) due to its high specific surface area together with the special porous structure. Moreover, MNFSs show good availability of reusing to remove Cr(VI) ions.

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