Synthesis of Alumina with Mesopores by the Microwave-Assisted Method of Combustion Using Low Fuel Content

Reference	Presenter	Authors (Institution)	Abstract
17-050	HELOISA PIMENTA MACEDO	Medeiros, R.L.(UFRN); MACEDO, H.P.(Universidade Federal do Rio Grande do Norte); Melo, D.M.(UFRN); SILVA, F.M.(Universidade Federal do Rio Grande do Norte); MELO, M.A.(Universidade Federal do Rio Grande do Norte); Braga, R.M.(Escola Agricola de Jundiaí); OLIVEIRA, �.A.(Univerisade Federal do Rio Grande do Norte);	The alumina (?-Al2O3) range with specific area above 200 m² / g and narrow distribution of pore size was obtained quickly, practically and inexpensively by the microwave assisted combustion route. The factors that contributed to the synthesis of ?-Al2O3 were the low power of the microwave (450 W) combined with the low fuel content (urea). The obtained powders were calcined at temperatures of 550, 750 and 950°C (A550, A750 and A950, respectively) and characterized by X-ray diffraction (XRD), N2 fissisortion (BET-BJH), Fourier transform infrared spectrophotometry FTIR) and scanning electron microscopy (SEM). The results indicate that ?-Al2O3 formed at temperatures of 550 and 750°C. The ? and ? phases were identified in calcined alumina at 950 ºC (A950). The increase in the calcination temperature strongly influenced the decrease of the specific area and the pore volume, but did not present significant changes in the pore size distribution and in the crystallite size. The absorption spectra in the infrared region confirmed the phases and presence of nitrate after the combustion reaction. Thus, the proposed configurations in the microwave-assisted combustion synthesis allow the simple, fast and low-cost preparation of ?-Al2O3.
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