scholarly journals Microwave-Assisted Acid Activation of Clays Composed of 2:1 Clay Minerals: A Comparative Study

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 376 ◽  
Author(s):  
Juan Cecilia ◽  
Laura Pardo ◽  
Manuel Pozo ◽  
Eva Bellido ◽  
Francisco Franco
Keyword(s):  
Acid Treatment ◽  
Nitrogen Adsorption ◽  
High Specific Surface Area ◽  
Acid Activation ◽  
X Ray Diffraction ◽  
Octahedral Sheet ◽  
X Ray ◽  
Layer Sequence ◽  
Microwave Assisted ◽  
Scanning Electron

The effect of the microwave-assisted acid treatment (MAT) on the structure and texture of dioctahedral (montmorillonite) and trioctahedral (saponite) smectites, kerolitic clays and sepiolites were studied by scanning electron microscopy, nitrogen adsorption, X-ray fluorescence, X-ray diffraction and Fourier transform infrared spectroscopy. This study shows that in the smectite group of minerals the effectiveness of MAT is notably influenced by the chemical composition of the octahedral sheet, whereas in kerolitic clays it is influenced by the proportion of the expandable phase in the mixed layer sequence. On the other hand, the reactivity of sepiolites depends on the width of the natural fibres. With these treatments, extremely high specific surface area (SSA) increments are achieved in just 16 min. The SSA increments reach values up to 231 m2/g (%ΔSBET = 80) in sepiolites, 198 m2/g (%ΔSBET = 155) in Mg-smectites, and 161 m2/g (%ΔSBET = 61) in kerolitic clays.

Characterization of National Clays after Acid Treatment and Thermal

2014 ◽  
Vol 805 ◽  
pp. 662-666 ◽  
Author(s):  
Wellington Siqueira Lima ◽  
André Luiz Fiquene de Brito ◽  
Meiry Glaúcia Freire Rodrigues ◽  
Mariaugusta Ferreira Mota ◽  
Marcílio Máximo Silva
Keyword(s):  
Acid Treatment ◽  
Thermal Activation ◽  
Nitrogen Adsorption ◽  
Acid Activation ◽  
X Ray Diffraction ◽  
Natural Form ◽  
X Ray ◽  
The Common ◽  
Sorption Characteristics

The clay types, kaolinite and smectite, are the most used industrially, mainly due to its sorption characteristics. There have been several attempts to improve the quality and characteristics of the clays, modifying them with different techniques. Two of the common techniques are thermal activation and acid activation. For acid activation, hydrochloric acid was used with a reaction time of 1 hour while the thermal activation the samples calcined at 300oC for 24 hours. This work aims to characterize the gray clay (supplied by Süd-Chemie LTDA) and Brasgel (provided by Bentonit), both in its natural form, as well as in the acid and thermal activation form (300°C). Natural and treated clays were characterized by X-ray Spectroscopy Energy Dispersive (EDX), X-ray diffraction (XRD) and nitrogen adsorption (BET). The results showed a reduction of impurities in the samples and did not comprise changes in the structure of the constituent minerals.

Rapid Synthesis and Characterization of CuInS2 Prepared Using Microwave-Assisted Heating

2015 ◽  
Vol 775 ◽  
pp. 143-146
Author(s):  
Ming Kwen Tsai ◽  
Yueh Chien Lee ◽  
Chia Chih Huang ◽  
Sheng Yao Hu ◽  
Kwong Kau Tiong ◽  
...  
Keyword(s):  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Rapid Synthesis ◽  
X Ray ◽  
Sem Image ◽  
Microwave Assisted ◽  
Calcination Treatment ◽  
Scanning Electron

In this work, the CuInS2 nanoparticles are successfully synthesized by microwave-assisted heating technique and further calcined at 400 °C. The morphological, structural, and optical properties of the synthesized CuInS2 nanoparticles are investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), Raman scattering, and transmittance measurement, respectively. The SEM image shows the clear particle shape of the calcined CuInS2 nanoparticles. After calcination treatment, the fundamental (112) peak of the XRD spectrum and a broad Raman peak mixed with chalcopyrite and CuAu structures support the improved crystallinity of the calcined CuInS2 nanoparticles.

Morphology Control of the Nano-MnO2 by Microwave Hydrothermal Synthesis

2012 ◽  
Vol 624 ◽  
pp. 47-50
Author(s):  
Shi Lei Zhang ◽  
Ben Niu ◽  
Enlei Qi ◽  
Lei Wang ◽  
Jie Qiang Wang
Keyword(s):  
Hydrothermal Synthesis ◽  
Energy Dispersive Spectrometer ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Crystal Forms ◽  
X Ray ◽  
Microwave Assisted ◽  
Structure And Morphology ◽  
Microwave Hydrothermal ◽  
Scanning Electron

In this paper, KMnO4 was used as raw material, nano-MnO2 with different morphologies such as flowers globular, hollow tubular and rodlike were obtained by the microwave assisted hydrothermal synthesis under the acidic condition. The crystal structure and morphology of the resultant MnO2 were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM), respectively. The elements and content of samples were tested by Energy Dispersive Spectrometer (EDS). The influence of reaction temperature and holding time on crystal forms and morphologies of the MnO2 was analyzed.

scholarly journals Characterisation of Natural and HDTMA-Br Modified Dijah-Monkin Bentonite Clay: FTIR, XRF, XRD and SEM

2021 ◽  
Vol 7 (5) ◽  
pp. 2010-2018
Author(s):  
Olukayode Gideon Oloyede ◽  
◽  
Umar Omeiza Aroke ◽  
Saidat Olanipekun Giwa ◽  
Alexander Asanja Jock ◽  
...  
Keyword(s):  
Cation Exchange Capacity ◽  
Bentonite Clay ◽  
Exchange Capacity ◽  
Basal Spacing ◽  
Hexadecyltrimethylammonium Bromide ◽  
Acid Activation ◽  
X Ray Diffraction ◽  
X Ray ◽  
North East ◽  
Scanning Electron

In this study, Dijah-Monkin bentonite clay was modified with a cationic surfactant hexadecyltrimethylammonium bromide (HDTMA-Br) at the level of twice the cation exchange capacity (CEC). This process results in the development of hydrophobic organoclay with an improved adsorption capacity. The clay obtained from Zing LGA Taraba State, North-East Nigeria, was beneficiated and pulverised to a particle size of 125 µm. The modification was performed without acid activation to prevent damages to the clay’s crystal structure. The organoclay was characterised for chemical composition, functional groups, mineralogical and surface morphology using X-ray fluorescence (XRF), Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The XRD showed an increase in the basal spacing from 15.681Å to 17.758 Å, while the XRF revealed a 5.35% concentration of Br on the modified clay, indicating successful intercalation. The FTIR spectra also revealed the appearance of symmetric and asymmetric stretching bands at 2847.7cm-1 and 2914.8cm-1, respectively, as a consequence of the modification, resulting in more sites for adsorption.

Microstructure of Nanocrystalline Ceramics

1988 ◽  
Vol 132 ◽  
Author(s):  
H. Hahn ◽  
J. Logas ◽  
H. J. Höfler ◽  
Th. Bier ◽  
R. S. Averback
Keyword(s):  
Grain Growth ◽  
Sintering Temperature ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Green Body ◽  
X Ray Diffraction ◽  
Adsorption Method ◽  
X Ray ◽  
Nanocrystalline Ceramics ◽  
Scanning Electron

ABSTRACTThe microstructure of nanocrystalline (n-) TiO2 was studied as a function of sintering temperature up to 1273 K. Grain growth was monitored using x-ray diffraction and scanning electron microscopy. Measurements of density and permeability of He and Ar were also conducted. The specific surface area and the total pore volume were determined quantitatively using the nitrogen adsorption method. These measurements revealed that highly compacted n-TiO2 had green body densities as high as 75 % of bulk density and that sintering occurred at much lower temperatures than in conventional powder. Densification proceeded by loss of the small pores first. The possibilities of achieving high densities with limited grain growth will be discussed.

Mechanism of Microwave Assisted Technique Acid Leaching Coal Gangue

2014 ◽  
Vol 1030-1032 ◽  
pp. 116-120
Author(s):  
Cheng Long Liu ◽  
Ju Pei Xia ◽  
Yu Chong Xie
Keyword(s):  
Acid Leaching ◽  
Coal Gangue ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Characterization Methods ◽  
X Ray ◽  
Microwave Assisted ◽  
Leaching Methods ◽  
Related Process ◽  
Scanning Electron

The coal gangue are produced in a coal mine heap of Pan xian, Gui zhou, by using microwave assisted acid leaching methods and under certain reaction conditions, the products of different stages of acid leaching were characterized through different characterization methods like X-ray diffraction, scanning electron microscope and energy dispersive spectroscopy. The related process mechanism of Microwave assisted technique acid leaching gangue was preliminarily studied by the characterization results from analyzing the products of different stages of acid leaching.

Microwave-Assisted Preparation of Cu2O Octahedral Microcrystals

2011 ◽  
Vol 284-286 ◽  
pp. 746-749
Author(s):  
Chong Hai Deng ◽  
Han Mei Hu ◽  
Ming Di Yang
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Growth Mechanism ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
X Ray ◽  
Microwave Assisted ◽  
Morphology And Structure ◽  
Scanning Electron

In this paper, we reported a facile microwave-assisted green chemical route to prepare pure, uniform, and monodispersed Cu2O octahedron wrapped by the {111} faces by using glucose as a reducing agent. X-ray diffraction (XRD), energy dispersive X-ray spectrometry(EDX) and field emission scanning electron microscopy (FESEM) were used to characterize the as-synthesized products. It was found that the morphology and structure of Cu2O crystals were greatly affected by the concentration of NaOH. A solid-solution-solid growth mechanism was possibly proposed on the basis of the comparative experimental results.

scholarly journals The ultrasound effect on the morphological properties of hydroxyapatite

2018 ◽  
Vol 243 ◽  
pp. 00012 ◽  
Author(s):  
Konstantin Chuprunov ◽  
Eugenii Kolesnikov ◽  
Igor Ilinykh ◽  
Andrey Yudin ◽  
Denis Leybo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ultrasonic Treatment ◽  
Nitrogen Adsorption ◽  
Morphological Properties ◽  
Pressure Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ultrasound Assisted ◽  
Ultrasound Effect ◽  
Scanning Electron

The present study considers the morphological and dispersity characteristics of hydroxyapatite (HAp) samples synthesised through the ultrasound-assisted hydrothermal method with additional pressure treatment. The samples were analyzed by the X – Ray diffraction, scanning electron microscopy, low-temperature nitrogen adsorption. The ultrasound effect on the HAp morphologiy and dispersity was studied. The pressure assisted ultrasonic treatment made possible obtaining HAp samples with different morphology from rods and flakes to particles with irregular shape close to spherical. Also pressure assisted ultrasonic treatment able to increase the porosity of HAp materials.

Bimetallic Ni-Mo Nitride as the Carbon Dioxide Hydrogenation Catalyst

2013 ◽  
Vol 872 ◽  
pp. 3-9 ◽  
Author(s):  
Denis V. Leybo ◽  
Natalia I. Kosova ◽  
Konstantin O. Chuprunov ◽  
Denis V. Kuznetsov ◽  
Irina A. Kurzina
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Scanning Electron Microscopy ◽  
Contact Time ◽  
Nitrogen Adsorption ◽  
Hydrogenation Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Dioxide Hydrogenation ◽  
Scanning Electron

The possibility of bimetallic Ni-Mo nitrides usage as the catalysts in carbon dioxide hydrogenation reaction was examined in this work. Powders were synthesized through thermo-programmed reduction of precursor, which was produced by evaporation of the metal-containing solution. Specimens were investigated by x-ray diffraction, thermogravimetry, low-temperature nitrogen adsorption and scanning electron microscopy. It is shown that final powders provide CO2 conversion of 29 % for contact time of 0.26 s.

Alcohol Sensing Properties of SnO2/CNT Nanocomposites Synthesized by Microwave-Assisted Process

2016 ◽  
Vol 675-676 ◽  
pp. 85-88
Author(s):  
Nalita Sawangjit ◽  
Wicharn Techitdheera ◽  
Wisanu Pecharapa
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Structural Morphology ◽  
X Ray ◽  
Multi Wall Carbon Nanotubes ◽  
Microwave Assisted ◽  
Sensing Sensitivity ◽  
Scanning Electron

SnO2/CNT nanocomposites were synthesized via microwave-assisted process using SnCl4·5H2O as a starting precursor and UV-treated multi-wall carbon nanotubes (MWCNTs) as scaffolds. The concentration of SnCl4 was varied in the range of 0.01-0.05 M. Effect of precursor concentration on their physical properties and micro structural morphology were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD results indicate that the as-synthesized composites are the mixture of two separated phases including SnO2 and MWCNT. SEM images indicate that the surfaces of MWCNT are thoroughly covered with SnO2 nanoparticles. Comparative gas sensing result reveals that the prepared hybrid SnO2/MWCNT composites exhibit much higher sensing sensitivity and recovery property in detecting alcohol gas at room temperature than the bare SnO2.

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