PRODUCTION AND CHARACTERIZATION OF ALUMINA NANOPARTICLES FROM GIRO CLAY VIA ACID LEACHING WITH SOL GEL METHOD

Author(s):  
S. O. Balogun ◽  
S. A. Yaro ◽  
M. Abdulwahab ◽  
A. Kasim

Alumina nanoparticles were synthesized from locally available high alumina clay, obtained from Giro in Kabbi State, through acid leaching with sol-gel method. The clay was leached with hydrofluoric acid and the aluminous solution produced was used as precursor to synthesis nanoparticles through sol gel process. The composition and structure of the clay and the particles produced were characterized using Fourier Transform Infrared (FTIR), X-ray diffraction and fluorescence Spectroscopic techniques, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). From the analyses, the clay sample was observed to be high in alumina and predominantly Kaolinitic in nature. During the sol-gel process, effective flocculation was obtained at slightly alkaline pH range (7.6 to 8.0) and a relative moderate temperature of 80oC. The result also shows that the aging time of the gel affected the size of the particles produced during the process, and the particles are mainly nano-alumina.

2016 ◽  
Vol 254 ◽  
pp. 200-206 ◽  
Author(s):  
Catalina Nuțescu Duduman ◽  
María Isabel Barrena Pérez ◽  
José Maria Gómez de Salazar ◽  
Ioan Carcea ◽  
Daniela Lucia Chicet ◽  
...  

Nanostructured SnO2 was prepared based on the sol-gel method used in the preparation of crystalline metal oxides. Sol-gel process can be described as a forming network of oxide polycondensation reaction of a molecular precursor in a liquid. Six experiments were carried out. Morphological structures and chemical composition were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) after calcination. It is noted that TEM images show that the spheres consist from nanocrystals, quantitative EDS analysis of the chemical composition shows an absence of the chlorine, which is a desired fact. For structural characterization of the material we used X-Ray Diffraction (XRD). The X-ray diffraction pattern for all samples indicates peaks which are agreeable with standard diffraction pattern of SnO2. The particle size of all samples was in the range of 28-92 nm calculated according to Scherrer equation.


1991 ◽  
Vol 30 (Part 2, No. 6A) ◽  
pp. L1052-L1055 ◽  
Author(s):  
Kumi Okuwada ◽  
Shin-ichi Nakamura ◽  
Motomasa Imai ◽  
Keiichi Kakuno

2018 ◽  
Vol 41 (3-4) ◽  
pp. 53-62 ◽  
Author(s):  
Behnaz Lahijani ◽  
Kambiz Hedayati ◽  
Mojtaba Goodarzi

Abstract In this work, the PbFe12O19 nanoparticles were prepared by the simple and optimized precipitation method with different organic surfactants and capping agents. In the next step, the TiO2 nanoparticles were synthesized using the sol-gel method. At the final step, the PbFe12O19-TiO2 nanocomposites were prepared via the sol-gel method. The effect of the precipitating agent on the morphology and particle size of the products was investigated. The prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The results obtained by the vibrating sample magnetometer show the magnetic properties of the ferrite nanostructures. The photocatalytic effect of the PbFe12O19-TiO2 nanocomposite on the elimination of the azo dyes (acid black, acid violet and acid blue) under ultraviolet light irradiation was evaluated. The results indicate that the prepared nanocomposites have acceptable magnetic and photocatalytic performance.


2020 ◽  
Vol 840 ◽  
pp. 454-458
Author(s):  
Adya Rizky Pradipta ◽  
Kurniawan Mauludi ◽  
Indriana Kartini ◽  
Eko Sri Kunarti

TiO2 modified Fe3O4 nanocomposite as photocatalyst in CO2 indirect reduction was synthesized by an ultrasonic-assisted sol-gel method and its photocatalytic activity was studied as well. The modification of the TiO2 composite was attempted to modify titanium dioxide to have better performance as a photocatalyst. Magnetite synthesis was carried out by the sono-coprecipitation method with the addition of the capping agent. The magnetite was coated with TiO2 via the sol-gel method under ultrasonic irradiation. The products were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectrophotometry (FT-IR), transmission electron microscopy (TEM), and turbidimetry. The final product was also analyzed by diffuse reflectance UV-Visible (DR-UV) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX). The product of indirect reduction was analyzed by gas chromatography-mass spectrometry (GC-MS). Photocatalytic reaction with Fe3O4/TiO2 nanocomposite produced a higher concentration of methanol than using TiO2. Methanol concentration produced from the photocatalytic reaction using TiO2 and Fe3O4/TiO2 was 6.63% and 16.82%.


2007 ◽  
Vol 280-283 ◽  
pp. 839-844
Author(s):  
Hui Qing Fan

Relaxor-based 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) thin films were grown epitaxially on silicon substrates by sol-gel method and PbO cover coat technique, and investigated by x-ray diffraction, auger electron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The phase development and microstrure evolution of the PMN-PT film were significantly affected by the final annealing temperature and time. A perovskite PMN-PT film was obtained after annealing at 850oC for 1 min. Then, highly <100>-oriented and textured PMN-PT films could be achieved by using a LaNiO3 perovskite template.


2021 ◽  
Author(s):  
V Maphiri ◽  
L Melato ◽  
Mhlongo ◽  
TT Hlatshwayo ◽  
TE Motaung ◽  
...  

Abstract Un-doped and ZnAlxO(1.5x + 1):0.1% Tb3+ (ZAOT) nano-powders were synthesized via citrate sol-gel method. The Alx moles were varied in the range of 0.25 ≤ x ≤ 5.0. The X-ray powder diffraction (XRD) data revealed that for the x < 1.5, the prepared samples crystal structure consists of mixed phases of the cubic ZnAl2O4 and hexagonal ZnO phases, while for the x ≥ 1.5 the structure consists of single phase of cubic ZnAl2O4. This was confirmed by the Raman and Fourier-Transform Infrared (FTIR) vibrational spectroscopy. Scanning electron microscopy (SEM) showed that varying Alx moles influences the morphology while Transmission electron microscopy (TEM) shows the dual morphology at x < 1.5. The photoluminescence (PL) revealed intense and distinct emissions attributed to both the host and Tb3+ transitions. The emission intensity highly depends on the Alx moles. The International Commission on Illumination (CIE) colour chromaticity showed that the emission colour could be tuned by varying the Alx moles.


2018 ◽  
Vol 17 (05) ◽  
pp. 1850003 ◽  
Author(s):  
V. Usha ◽  
R. Vettumperumal ◽  
S. Kalyanaraman ◽  
R. Thangavel

Nanocrystalline nickel oxide (NiO) were prepared by low cost sol–gel method and analyzed using X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectra (EDX), Raman, photoluminescence (PL) and UV-Vis-NIR spectroscopic techniques. XRD spectrum confirmed the face centered cubic structure of NiO nanoparticles and it showed polycrystalline nature without any impurity. Magnetic ordered phase related modes of NiO nanoparticles was observed from Raman spectra, which also confirmed the absence of secondary phases in NiO nanoparticles. Linear and nonlinear refractive index and optical susceptibility of NiO nanoparticles were calculated and discussed using Tauc’s method and Wemple and DiDomenico single oscillator model. Calculated maximum value of third ordered nonlinear optical susceptibility ([Formula: see text] is [Formula: see text] revealed that the NiO nanoparticles were suitable in nonlinear optical devices applications. Simulation of second harmonic efficiency, spectral band width and quasi phase matching of NiO nanocrystals are discussed using optiFDTD.


2019 ◽  
Vol 64 (1) ◽  
pp. 61-74 ◽  
Author(s):  
Behnam Khanizadeh ◽  
Morteza Khosravi ◽  
Mohammad A. Behnajady ◽  
Ali Shamel ◽  
Behrouz Vahid

In this study, La and Mg doped, and co-doped ZnO nanoparticles were prepared using the sol-gel method. The prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), and N2 physisorption techniques. The XRD results indicated that the prepared nanoparticles can be well adopted by the hexagonal wurtzite structure crystal and there are no second impurity peaks. Studies of the FESEM, EDX and TEM have shown that the samples have uniform spherical-like morphology with a homogenous distribution. The incorporation of La and Mg into the ZnO lattice had no effect on the morphology of the nanoparticles, but a reduction in the size of the grains (≈ 14 nm to ≈ 7 nm) was observed due to the insertion of these ions. The results of N2 physisorption indicated that there was an increase in BET surface area and pore volume for doped and co-doped samples. The results of DRS showed an increase in band gap energy and a blue shift at the absorption edge for doped and co-doped samples. The photocatalytic activity of the prepared catalysts was evaluated in the removal of RhB under UVA irradiation. The results showed that Mg5%-La5%/ZnO had the highest photoactivity (91.18 %) among all samples.


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