The effect of synthesis routes on the development of ordered mesoporous alumina by precipitation method

Abstract

A precipitation method is proposed for easy, fast and inexpensive method to prepare ordered mesoporous alumina (MA) by using ammonium acetate (NH 4(CH3COO)) as precipitating agent. The aluminium acetate (Al(CH3COO) 3) precipitate obtained was subjected to nitric acid (HNO3) and ultrasonic treatments. The effect of calcination temperature on phase transformation and mesoporosity was investigated by calcining the samples at 650 °C and 750 °C. N2-adsorption analysis indicated that samples calcined at 650 °C exhibited higher BET surface area (> 200 m2/g), higher pore volume and smaller pore size distributions compare to samples calcined at 750 °C. FESEM and TEM micrographs of all samples calcined at 650 °C showed non-homogenous spherical particles but homogeneous pore size in ~ 8-10 nm. Ultrasonic treatment on MA samples results in narrower pore size distribution with FWHM peak in the range of 2-3.2 nm as compared to MA without ultrasonic treatment giving peak with FWHM 8.2 nm. The results obtained indicate that calcination temperature and ultrasonic treatment are greatly affect on the development of highly ordered and high surface area mesoporous alumina.