scholarly journals Interzeolitic Transformation of Clinoptilolite into GIS and LTA Zeolite

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1313
Author(s):  
Renata C. F. de Lima ◽  
Daniele da Silva Oliveira ◽  
Sibele B. C. Pergher
Keyword(s):  
Electron Microscopy ◽  
X Ray Diffraction ◽  
Synthesis Time ◽  
X Ray ◽  
Synthesis Conditions ◽  
Environmentally Sustainable ◽  
Lta Zeolite ◽  
Clinoptilolite Zeolite ◽  
Natural Clinoptilolite ◽  
Scanning Electron

A natural clinoptilolite zeolite was transformed into other zeolites of greater industrial interest, such as zeolites with GIS and LTA structures. The synthesis conditions were studied, and the interzeolitic transformation was characterized by X-ray diffraction (XRD), X-ray fluorescence (FRX), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). From the results, it was possible to observe that the GIS and LTA zeolites were successfully synthesized. Furthermore, the results revealed that a synthesis time of 4 days was enough to obtain the GIS structure, and 4 h was sufficient to obtain LTA. The interzeolitic transformation can be explained by the RBU (Ring Building Unit) approach using C4 units from the HEU topology. The use of clinoptilolite in the synthesis of other zeolites is an innovative, economically viable, and environmentally sustainable process that exploits a material that exists in large quantities and is still little explored by industry.

scholarly journals K-paracelsian (KAlSi3O8·H2O) and identification of a simple building scheme of dense double-crankshaft zeolite topologies

IUCrJ ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Cristian-R. Boruntea ◽  
Peter N. R. Vennestrøm ◽  
Lars F. Lundegaard
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Space ◽  
Ex Situ ◽  
Zeolite Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Small Pore ◽  
Scanning Electron

During screening of the phase space using KOH and 1-methyl-4-aza-1-azoniabicyclo[2.2.2]octane hydroxide (1-methyl-DABCO) under hydrothermal zeolite synthesis conditions, K-paracelsian was synthesized. Scanning electron microscopy, energy dispersive X-ray spectroscopy and ex situ powder X-ray diffraction analysis revealed a material that is compositionally closely related to the mineral microcline and structurally closely related to the mineral paracelsian, both of which are feldspars. In contrast to the feldspars, K-paracelsian contains intrazeolitic water corresponding to one molecule per cage. In the case of K-paracelsian it might be useful to consider it a link between feldspars and zeolites. It was also shown that K-paracelsian can be described as the simplest endmember of a family of dense double-crankshaft zeolite topologies. By applying the identified building principle, a number of known zeolite topologies can be constructed. Furthermore, it facilitates the construction of a range of hypothetical small-pore structures that are crystallo-chemically healthy, but which have not yet been realized experimentally.

Effect of Synthesis Conditions and Actinide Contents on Phase Composition of Actinide Bearing Ceramics

2003 ◽  
Vol 807 ◽  
Author(s):  
A. G. Ptashkin ◽  
S. V. Stefanovsky ◽  
S. V. Yudintsev ◽  
S. A. Perevalov
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Phase Composition ◽  
Fluorite Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Reducing Conditions ◽  
Dispersive System ◽  
Scanning Electron

ABSTRACTPu-bearing zirconolite and pyrochlore based ceramics were prepared by melting under oxidizing and reducing conditions at 1550 °C. 239Pu content in the samples ranged between ∼10 and ∼50 wt.%. Phase composition of the ceramics and Pu partitioning were studied using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive system (SEM/EDS). Major phases in the samples were found to be the target zirconolite and pyrochlore as well as a cubic fluorite structure oxide. Normally the Pu content in the Pu host phases was 10–12 wt.%. This corresponds to the Pu content recommended for matrices for immobilization of excess weapons plutonium. At higher Pu content (up to 50 wt.%) additional phases, such as a PuO2-based cubic fluorite-structured solid solution, perovskite, and rutile were found.

Platinum Reduction Study on Pt/C Electro-catalysts for PEMFC

2013 ◽  
Vol 16 (3) ◽  
pp. 141-145
Author(s):  
M.L. Hernandez-Pichardo ◽  
R. Gonzalez-Huerta ◽  
P. del Angel ◽  
E. Palacios-Gonzalez ◽  
M. Tufiño-Velazquez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Uv Light ◽  
Reducing Agents ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Platinum Species ◽  
Scanning Electron

Platinum reduction on Pt/C catalysts was studied on samples prepared by the impregnation method using different Pt precursors and reducing agents such as ethanol, sodium borohydride and ethanol-UV light (photo-assisted reduction), in order to compare the efficiency of the different reducing agents. The influence of the reduction level of the platinum species on the electrochemical behavior of these catalysts has been determined. The catalysts were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and linear and cyclic voltammetry. The results show that the reduction level depends mainly on the platinum precursor. Moreover, it was found that the higher electrochemical activity was found using catalysts reduced with ethanol, whereas by using NaBH4 as the reducing agent, the total reduction of the platinum precursor is very difficult in same synthesis conditions. The analysis of the XPS results shows that samples reduced with ethanol presented the lower PtOx/Pt reduction ratio.

Nanostructured Morphology of Spinel LiMn2O4 Oxide under Microwave Heating

2014 ◽  
Vol 936 ◽  
pp. 452-458
Author(s):  
Di Huo
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Morphology ◽  
Microwave Heating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Morphology And Structure ◽  
Scanning Electron

The surface morphology and structure of the cubic stoichiometric spinel LiMn2O4powder prepared by microwave heating were examined using X-ray diffraction, scanning electron microscopy and transmittance electron microcopy. It is shown that the surface morphology of LiMn2O4particle changed with increasing preparing temperature, while the crystal structure kept unchanged. Novel nanostructured morphologies including nanorods and nanowhiskers were formed under appropriate synthesis conditions. The growth mechanism of the nanostructured morphology of spinel LiMn2O4was discussed in accordance with period bonding chains (PBCs) theory.

scholarly journals Influence of Synthesis Method on LTA Time-Dependent Stability

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2122 ◽  
Author(s):  
Claudia Belviso ◽  
Antonio Lettino ◽  
Francesco Cavalcante
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Process ◽  
Synthesis Method ◽  
Synthetic Zeolite ◽  
Time Dependent ◽  
Time Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lta Zeolite ◽  
Scanning Electron

Time-stability of LTA zeolite formed by hydrothermal method with or without the action of ultrasonic irradiation was investigated by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The results show that 6 months after the synthesis by hydrothermal process with continuous sonication, LTA evolves into a more stable sodalite, whereas no differences are detected 12 months after LTA synthesis by conventional pre-fused hydrothermal process. These data confirm that using the two approaches, different mechanisms control both zeolite crystallization and time-stability of the newly-formed mineral at solid state. The results are particularly important in the light of the synthetic zeolite application.

Ultrasonic Synthesis of SrTiO3

2014 ◽  
Vol 975 ◽  
pp. 56-60
Author(s):  
Olívia Andrade Raponi ◽  
André Silva Chaves ◽  
Maria Virgínia Gelfuso ◽  
Daniel Thomazini
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Electrical Energy ◽  
Ultrasound Irradiation ◽  
Synthesis Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Ultrasonic Synthesis ◽  
Scanning Electron

Thermoelectric ceramics convert thermal into electrical energy, based on the Seebeck effect. In order to improve this energy conversion, the grain size of these ceramics must be in nanometric scale to reduce the thermal conductivity and electrical resistivity. Thus, nonconventional synthesis methods are being studied to produce nanoparticles, such as ultrasound synthesis technique (USS). These methods can produce powders with particles size lower than conventional synthesis, as compared to solid-state reaction (SSR), for example. In this study, strontium titanate (STO) based ceramics were synthesized by SSR and USS with 30, 40 and 50 minutes of ultrasound irradiation of 5W/ml power. The powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). There have been obtained powders of ~140nm crystallite size using USS method during 40minutes, which has proven to be the best ultrasound synthesis conditions i

Synthesis of Nanotubular Titanate from Titanium Using Hydrothermal Treatment

2006 ◽  
Vol 317-318 ◽  
pp. 247-250 ◽  
Author(s):  
T. Kubo ◽  
W. Kato ◽  
Yuki Yamasaki ◽  
Atsushi Nakahira
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Aqueous Solution ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Transmission Electron ◽  
Scanning Electron

In this study, the synthesis of nanotubular titanate was attempted though heat-treatment in an oil bath (non-hydrothermal treatment), heat-treatment with stirring in an oil bath (non-hydrothermal treatment), or hydrothermal treatment for metal Ti in NaOH aqueous solution systems. Obtained products were characterized by various methods, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD results suggested that products obtained by both hydrothermal treatment and heat-treatment in an oil bath with and without stirring could be identified as H2Ti4O9H2O. From TEM observations, however, various morphologies for products obtained by these treatments were confirmed. Therefore, it was considered that morphologies of these products strongly depended on synthesis conditions.

Influence of Power and Synthesis Time in the Formation of Mullite Obtained by Microwave Heating

2015 ◽  
Vol 820 ◽  
pp. 90-95 ◽  
Author(s):  
Lisiane Navarro de Lima Santana ◽  
Josileido Gomes ◽  
Valmir José da Silva ◽  
Wherllyson Patrício Gonçalves ◽  
Hélio de Lucena Lira ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Microwave Heating ◽  
Rapid Heating ◽  
X Ray Diffraction ◽  
Synthesis Time ◽  
X Ray ◽  
Mullite Phase ◽  
Kinetics Of ◽  
Scanning Electron

Front of the large number of applications of the mullite mineral, many researchers seek to synthesize it from the mixture of Al2O3and SiO2powders, or from aluminossilicates, such as smectite. The synthesis of mullite from clays via rapid heating by microwaves emerges as an alternative process. This process accelerates the kinetics of nucleation and the development of mullite phase. Thus, the aim of this work is to study the effect of power and timeon synthesis of mullite from clay, via rapid heating in microwave. The synthesis times were 15 and 20 minutes, with powers of 1.26 and 1.44kW. The obtained powderswere characterized by X-ray diffraction and scanning electron microscopy. The best results were obtained with a power of 1.44kW for 20 minutes.

Controlled Growth of SnO2 Micro/Nanocrystals with Different Morphologies via a Solution Method

2009 ◽  
Vol 66 ◽  
pp. 155-158 ◽  
Author(s):  
Tie Kun Jia ◽  
Wei Min Wang ◽  
Zheng Yi Fu ◽  
Fei Huang ◽  
Hao Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solution Method ◽  
Sno2 Nanoparticles ◽  
X Ray Diffraction ◽  
Forming Process ◽  
X Ray ◽  
Synthesis Conditions ◽  
Sno2 Nanocrystals ◽  
Scanning Electron

SnO2 nanocrystals with various morphologies were synthesized via a hydrothermal method assisting by the surfactant CTAB. The morphologies of the products were significantly dependent on the synthesis conditions. The products were characterized by X-ray diffraction (XRD) and field scanning electron microscopy (FESEM).The results showed products SnO2 nanoparticles and spheres like structure assembled with nanocones were obtained by varying the dosage of CTAB and the concentration of NaOH. The forming process of SnO2 sphere like structure was discussed and the proposed mechanism was put forward in this work.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

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