Facile and rapid auto-combustion synthesis of nano-porous γ-Al2O3 by application of hexamethylenetetramine in fuel composition

In this article, urea, glycine and hexamethylenetetramine were blended in accordance with the mixture design algorithm to prepare gamma-Al2O3 by auto-combustion technique. Aluminum nitrate was then mixed with the stoichiometric contents of prepared fuel solutions to obtain gel systems. The gels exhibited a typical self-propagating combustion behavior at low temperature, directly resulting amorphous materials. The precursors were calcined at various temperatures ranging from 700 to 900 degrees C. The treated powders were evaluated by determining the methylene blue (MB) adsorption efficiency. The production condition to obtain gamma-Al2O3 with maximum surface area depends on fuel composition and calcination temperature. The alumina powder fabricated by this procedure was uniformly distributed and contains nano-sized secondary particles with diameter about 10-30 nm in which the average pore size is 3.2 nm induced large surface area, 240 m(2)g(-1). The employment of hexamethylenetetramine provides a potential for synthesis of gamma-Al2O3 at lower temperature, 700 degrees C, with maximum MB removal efficiency.