Rapid synthesis and characterization of mesoporous nanocrystalline MgAl₂O₄ via flash pyrolysis route

Abstract

a b s t r a c tIn this work, we demonstrate an effective, fast and low-cost route for the synthesis of mesoporous MgAl 2 O 4 powder. This synthesis procedure successfully reduces the overall synthesis time for nanosized MgAl 2 O 4 powder from days to a few hours. The as-synthesized powder was found to be amorphous in nature. Upon calcination at 700 • C (2 h) and 900 • C (4 h) in presence of air, the as-synthesized MgAl 2 O 4 amorphous powder was transformed into a disorder and order nanocrystalline phase respectively. The structural information of evolvement phase was analyzed through Rietveld refinement technique and Fourier transform infrared spectroscopy. The specific surface area of MgAl 2 O 4 powder calcined at 700 • C and 900 • C was found to be 118.14 m 2 /g and 74.67 m 2 /g, respectively.

Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion

“…It confirmed that there was also formation of stoichiometric magnesium aluminate spinel in all samples obtained in the present study. The shoulder observed at about 800 cm -1 is consistent with the hypothesis that some Al 3+ ions also occupy tetrahedral positions in the spinel formed 27 . It was observed that all spectra showed very similar profiles, in which bands with absorption maxima around 3500 cm -1 and 1650 cm -1 were identified, attributed to the stretch vibrations of O-H groups, and of H-O-H molecules deformation of the water physically adsorbed and in interaction with MgAl 2 O 4 , respectively 3,19,28 ; an absorption band at about 2339 cm -1 , referring to the stretch vibration of C=O bond of the carbon dioxide from the air 27 ; in addition to the band with the maximum absorption, around 1370 cm -1 , attributed to the vibrations of the N-O bond of NO 3-groups.…”

“…2a, are typical of the spinel structure of magnesium aluminate 3,16,19,24,27,28 . In a recent work, Erukhimovitch et al 24 detected four main vibrations modes (γ 2 , γ 1 , γ 5 and γ 6 ) at about 523, 692, 828 and 910 cm -1 in the FTIR spectrum of stoichiometric magnesium aluminate spinel.…”

“…There are several processes to prepare nanocrystalline magnesium aluminate, such as sol-gel [13][14][15][16] , co-precipitation 17 , complexation 1,18 , mechanical milling 3 , mechanical-chemical process 19 , hydrothermal 20 , micro emulsion 21 , combustion method 15,[22][23][24][25][26] and fast pyrolysis 27 . However, many of those are complex, expensive, have several steps, require long time for synthesis, require high temperatures and produce nonhomogeneous and generally low surface area solids 28 .…”

Effect of glycine–starch mixing ratio on the structural characteristics of MgAl2O4 nano-particles synthesized by sol–gel combustion

“…Microwave-assisted high-energy ball milling has been used to prepare MAS with a particle size of 28-149 nm (Bafrooei & Ebadzadeh, 2013). Precipitation (Mosayebi, Rezaei, Hadian, Kordshuli, & Meshkani, 2012), sol-gel (Ye, Oprea, & Troczynski, 2005), microwave (Ganesh, Srinivas, Johnson, Saha, & Mahajan, 2004), and pyrolysis (Tripathy & Bhattacharya, 2013) methods have been used to prepare nano-sized MAS, often involving expensive materials and laborious procedures.…”

Application of autoignition technique for synthesis of magnesium aluminate spinel in nano scale: Influence of starting solution pH on physico-chemical characteristics of particles

“…The synthetic MAS powder is produced by a variety of ceramic processing routes, including the wet-chemical process [5], precipitation [9], solegel [10e12], polymerized complex method [13], microwave [14,15] and pyrolysis [16]. Unfortunately many of these processing techniques are inherently complex to apply in the industrial scale and rigid control should be carried out over chemical compounds and morphology of particles.…”