scholarly journals Synthesis of mesoporous silica with ordered nanostructural morphology from natural quartz sand

2020 ◽  
Vol 64 (5) ◽  
pp. 544-550
Author(s):  
T. F. Kouznetsova ◽  
V. Е. Agabekov ◽  
A. I. Ivanets ◽  
E. V. Karpinchik ◽  
J. D. Sauka
Keyword(s):  
Quartz Sand ◽  
Molecular Sieves ◽  
Three Dimensional ◽  
Nitrogen Adsorption ◽  
Average Diameter ◽  
High Specific Surface Area ◽  
Mesoporous Molecular Sieves ◽  
X Ray Diffraction ◽  
Natural Quartz ◽  
Adsorption Desorption

Silica with ordered nanostructured morphology characteristic of mesoporous molecular sieves with cubic packing of cylindrical pores and a three-dimensional porous structure is obtained from natural quartz sand. It was shown by X-ray diffraction, scanning electron microscopy, and low-temperature nitrogen adsorption-desorption that the obtained silica material is thermally stable, amorphous, consists of submicron grains, has a high specific surface area of 1396 m2/g, a pore volume of 0.780 cm3/g and an average diameter of 2.2 nm with a narrow size distribution of mesopores.

SYNTHESIS, CHARACTERIZATION AND THE APPLICABILITY OF β-CYCLODEXTRINS FUNCTIONALIZED MESOPOROUS SBA-15 MOLECULAR SIEVES

NANO ◽  
2013 ◽  
Vol 08 (05) ◽  
pp. 1350050
Author(s):  
MIN GUAN ◽  
HAI-PENG BI ◽  
ZUYUAN WANG ◽  
SHAOHUA BU ◽  
LING HUANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Molecular Sieves ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Capacities ◽  
Transmission Electron ◽  
Potential Applications ◽  
Adsorption Desorption

Mesoporous silicas SBA-15 are modified with β-Cyclodextrins (β-CD) by simple grafting method. β-CD functionalized SBA-15 was characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), nitrogen adsorption–desorption measurements, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Furthermore, the applicability of it is investigated through studying the adsorption properties of clenbuterol. It showed better adsorption capacities of clenbuterol than pure SBA-15. β-CD functionalized SBA-15 material has the potential applications in the treatment of clenbuterol contamination in food and environment science.

Rice Straw and Rice Straw Ash as Precursor for Synthesis of Mesoporous Molecular Sieves MCM-41

2012 ◽  
Vol 550-553 ◽  
pp. 1391-1394
Author(s):  
Xiao Hong Tang ◽  
Bao Jun Li ◽  
Cheng Wei Li
Keyword(s):  
Rice Straw ◽  
Molecular Sieves ◽  
Mesoporous Structure ◽  
Mesoporous Molecular Sieves ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Temperature Programmed ◽  
Adsorption Desorption ◽  
Straw Ash ◽  
Mcm 41

In this paper, rice straw (RS) and rice straw ash (RSA) were employed to synthesize mesoporous molecular sieves MCM-41 in an open-vessel. The structure of as-synthesized MCM-41 was characterized by X-ray diffraction (XRD) pattern, Fourier transform infrared (FT–IR) spectrum, NH3-Temperature Programmed Desorption (TPD), and N2 adsorption-desorption isotherms. RS-MCM-41 and RSA-MCM-41 possess the same typical hexagonal mesoporous structure with high long-range order and crystalline degree as those of MCM-41 from water glass (SDS-MCM-41).

Preparation and Luminescence of Host-Guest (SBA-15)-(Arsenano-III) Nanocomposite Materials

2013 ◽  
Vol 785-786 ◽  
pp. 537-541
Author(s):  
Xiao Dong Li
Keyword(s):  
Low Temperature ◽  
Absorption Spectra ◽  
Molecular Sieves ◽  
Diffuse Reflectance ◽  
Nitrogen Adsorption ◽  
Nanocomposite Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Prepared Composite ◽  
Adsorption Desorption

The nanosized channels of SBA-15 molecular sieves were used as template and arsenano-III (ASA-III) was trapped inside the SBA-15 molecular sieves by means of liquid grafting method. The prepared nanocomposite materials were characterized by the powder X-ray diffraction, low temperature nitrogen adsorption-desorption and solid diffuse reflectance absorption spectra. The powder X-ray diffraction indicated the structure of the (SBA-15)-(ASA-III) still remains two-dimensional hexagonal mesostructrure. The low temperature nitrogen adsorption-desorption research showed that the ASA-III was present on the inner surface and partially occupied the channels of the molecular sieve. The UV-Vis solid state diffuse reflectance absorption spectra of the prepared composite materials showed the steroconfinmment effect of the host SBA-15 channels on the guest ASA-III and the guest was in the channels of the SBA-15 host. Luminous spectra showed that the prepared (SBA-15)-(ASA-III) nanocomposite materials have the investigating optical properties.

Rapid Synthesis of Mesoporous Molecular Sieve SBA-15 by Different Techniques with Microwave Assistance

2014 ◽  
Vol 805 ◽  
pp. 684-689
Author(s):  
Jocielys Jovelino Rodrigues ◽  
Ângela da Costa Nogueira ◽  
Meiry Gláucia Freire Rodrigues
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Molecular Sieves ◽  
Fiber Type ◽  
Nitrogen Adsorption ◽  
Mesoporous Molecular Sieve ◽  
Mesoporous Molecular Sieves ◽  
Molar Composition ◽  
Microwave Assistance ◽  
Adsorption Desorption

Mesoporous molecular sieves SBA-15 were prepared by using two different procedures taken from the scientific literature. In the first procedure, a hydrogel was prepared with the molar composition: 1.0 TEOS: 0017 P123: 5.7 HCl: 193 H2O with stirring at 35 °C. In the second procedure a hydrogel was prepared with the molar composition: 1.0 TEOS: 0017 P123: 8.14 HCl: 168 H2O with stirring at room temperature. In both procedures the samples were synthesized in a microwave. The samples were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), nitrogen adsorption-desorption analysis, and scanning electron microscopy (SEM). The analysis of XRD and nitrogen adsorption-desorption showed that the samples prepared with stirring at 35°C presented a higher ordering degree, an increase of crystallinity and larger volume of adsorbed nitrogen. The differential thermal analysis reveals that the SBA-15 presented high thermal stability, and the SEM revealed fiber type morphology consistent with this type of material.

Preparation of Mesoporous MCM-41 in Open-Vessel for Catalytic Synthesis of Geranyl Propionate

2012 ◽  
Vol 550-553 ◽  
pp. 358-361
Author(s):  
Xiao Hong Tang ◽  
Bao Jun Li ◽  
Chun Liang Han ◽  
Jin Wang ◽  
Cheng Wei Li
Keyword(s):  
Molecular Sieves ◽  
Mesoporous Structure ◽  
Mesoporous Molecular Sieves ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Ft Ir ◽  
Temperature Programmed ◽  
Geranyl Propionate ◽  
Adsorption Desorption ◽  
Mcm 41

In this paper, the synthesis of mesoporous molecular sieves MCM-41 was carried out in an open-vessel. The mesoporous structure of as-synthesized MCM-41 was characterized by X-ray diffraction (XRD) pattern, Fourier transform infrared (FT–IR) spectrum, NH3-Temperature Programmed Desorption (TPD), and N2 adsorption-desorption isotherms. The catalytic performances of MCM-41 for the synthesis of geranyl propionate (GP) with geraniol and propionic acid as reagents also were investigated. The characterization results show that the as-synthesized MCM-41 possesses typical hexagonal mesoporous structure with high long-range order and crystalline degree. The high GP selectivity of 64.25% with geraniol conversion of 17.21% was achieved under optimum conditions.

Application of raw and modified Uruguayan clays to phosphate adsorption for water remediation

MRS Advances ◽  
2018 ◽  
Vol 3 (61) ◽  
pp. 3543-3549
Author(s):  
Pablo González ◽  
Andrea C. De Los Santos ◽  
Jorge R. Castiglioni ◽  
María A. De León
Keyword(s):  
Nitrogen Adsorption ◽  
Pillared Clay ◽  
Water Remediation ◽  
Phosphate Adsorption ◽  
X Ray Diffraction ◽  
Order Model ◽  
Freundlich Model ◽  
X Ray ◽  
First Order ◽  
Adsorption Desorption

ABSTRACTA raw clay from Uruguay was modified with aluminium to obtain an aluminium pillared clay (Al-PILC). The solids were characterized by scanning electron microscopy, X-ray diffraction and nitrogen adsorption-desorption isotherms. The Al-PILC retained the typical laminar structure of montmorillonite. The specific surface area and the microporous volume of the Al-PILC, 235 m2 g-1 and 0.096 cm3 g-1, respectively, were much higher than those of the clay. The phosphate adsorption capacity of the Al-PILC was higher than those of the clay. The phosphate adsorption kinetic followed the pseudo-first-order model for both, the clay and the Al-PILC, and the phosphate adsorption isotherm for the Al-PILC fit the Freundlich model.

scholarly journals Highly Porous Carbon Materials Filled with Nickel Hydroxide Nanoparticles; Synthesis, Study, Application in Electrochemistry

2015 ◽  
Vol 17 (3) ◽  
pp. 187 ◽  
Author(s):  
Yu.A. Zakharov ◽  
A.N. Voropay ◽  
N.M. Fedorova ◽  
V.M. Pugachev ◽  
A.V. Puzynin ◽  
...  
Keyword(s):  
Porous Carbon ◽  
Nickel Hydroxide ◽  
Nitrogen Adsorption ◽  
Porous Carbon Material ◽  
X Ray Diffraction ◽  
Scanning Rate ◽  
Electrode Cell ◽  
Adsorption Desorption ◽  
Electrode Characteristics ◽  
Study Application

<p>Nickel hydroxide was deposited on the surface of the porous carbon to obtain a cathode material for supercapacitors. This work is the first part of the study of Ni(OH)<sub>2</sub>/С composite, which considers the conditions of its synthesis using two types of porous carbon matrices with a highly developed specific surface area (1000–3000 m<sup>2</sup>/g) and two types of precursors (NiCl<sub>2</sub>*6H<sub>2</sub>O and Ni(N<sub>3</sub>)<sub>2</sub>). The morphology of the systems, in particular the shape and size characteristics of the hydroxide filler particles, was examined using the scanning electron microscopy, X-ray diffraction, and nitrogen adsorption-desorption at 77 K. The measurements of capacity of the Ni(OH)<sub>2</sub>/С-electrodes were made in 6 M KOH using an asymmetric two-electrode cell (a porous carbon material with known electrode characteristics was employed as the counter electrode). The capacity was shown to decrease by 22–56% with increasing the scanning rate from 10 to 80 mV/s. A maximum capacity of the composite was obtained at a scanning rate of 10 mV/s was 346 F/g.</p>

Structural and surface aspects of thermally treated copper aluminium mixed hydroxides

1991 ◽  
Vol 69 (10) ◽  
pp. 1511-1515 ◽  
Author(s):  
Awad I. Ahmed ◽  
S. E. Samra ◽  
S. A. El-Hakam
Keyword(s):  
Pore Structure ◽  
Copper Content ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Structure Surface ◽  
Adsorption Desorption

CuO–Al2O3 catalysts containing various amounts of copper oxide have been prepared by precipitation. The phase changes were studied by X-ray diffraction. The results obtained revealed that the thermal treatment of solid CuO–Al2O3 at 700 °C produced only crystalline CuO. Heating to 900 °C led to the formation of copper alumina spinel together with unreacted CuO and γ-Al2O3. The spinel content was found to increase with increasing copper content. Nitrogen adsorption–desorption isotherms on the calcined samples have been measured. Surface areas have been calculated and the pore structure analysed. The textural properties of the system were found to depend on both the copper content and the calcination temperature. Key words: CuO, Al2O3 catalysts, structure, surface area, pore structure.

scholarly journals Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH4 Catalytic Combustion

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1771 ◽  
Author(s):  
Stefan Neatu ◽  
Mihaela M. Trandafir ◽  
Adelina Stănoiu ◽  
Ovidiu G. Florea ◽  
Cristian E. Simion ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Combustion ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Catalytic Combustion Of Methane ◽  
Adsorption Desorption

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium–manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H2–temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one. Indeed, the incipient impregnation of CeO2–MnOx catalyst, supported on an optimized amount of 4 wt.% La2O3–Al2O3, provided the best results of the catalytic combustion of methane on our catalytic micro-convertors. This is mainly due to: (i) the highest pore size dimensions according to the Brunauer-Emmett-Teller (BET) investigations, (ii) the highest amount of Mn4+ or/and Ce4+ on the surface as revealed by XPS, (iii) the presence of a mixed phase (Ce2MnO6) as shown by X-ray diffraction; and (iv) a higher reducibility of Mn4+ or/and Ce4+ species as displayed by H2–TPR and therefore more reactive oxygen species.

scholarly journals Preparation of Zirconia Nanofibers by Electrospinning and Calcination with Zirconium Acetylacetonate as Precursor

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1067 ◽  
Author(s):  
Vyacheslav V. Rodaev ◽  
Svetlana S. Razlivalova ◽  
Andrey O. Zhigachev ◽  
Vladimir M. Vasyukov ◽  
Yuri I. Golovin
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Heterogeneous Catalysts ◽  
Tetragonal Zirconia ◽  
Nitrogen Adsorption ◽  
Average Diameter ◽  
High Specific Surface Area ◽  
X Ray ◽  
Adsorption Analysis

For the first time, zirconia nanofibers with an average diameter of about 75 nm have been fabricated by calcination of electrospun zirconium acetylacetonate/polyacrylonitrile fibers in the range of 500–1100 °C. Composite and ceramic filaments have been characterized by scanning electron microscopy, thermogravimetric analysis, nitrogen adsorption analysis, energy-dispersive X-ray spectroscopy, and X-ray diffractometry. The stages of the transition of zirconium acetylacetonate to zirconia have been revealed. It has been found out that a rise in calcination temperature from 500 to 1100 °C induces transformation of mesoporous tetragonal zirconia nanofibers with a high specific surface area (102.3 m2/g) to non-porous monoclinic zirconia nanofibers of almost the same diameter with a low value of specific surface area (8.3 m2/g). The tetragonal zirconia nanofibers with high specific surface area prepared at 500 °C can be considered, for instance, as promising supports for heterogeneous catalysts, enhancing their activity.

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