Single step preparation of nano size gamma alumina exhibiting enhanced fluoride adsorption

Abstract

A direct single step solution combustion synthesis is adopted to prepare nano � -Al2O3 using aluminium nitrate as oxidizer and urea or hexamethylenetetramine (HMT) as fuel in the presence of a variety of surfactants. The obtained products were characterized by powder XRD and IR. The phase and size of the product was found to be depending on the nature of surfactant or fuel used. FESEM and TEM analysis of urea-surfactant based gamma alumina shows a fairly uniform spherical morphology of particle aggregates with lower nano size distribution of 40–60 nm. In HMT based � -Al 2 O 3 the particle size was greater than 200 nm. DLS analysis of the sample also showed the narrow size distribution in the urea-surfactant based � -Al 2 O 3 compared to HMT based � -Al 2 O 3 which shows broad size distribution. The nano gamma alumina powders also show specific area of 160–240 m 2 g −1 . The urea-CTAB synthesized � -Al 2 O 3 was tested for its fluoride adsorption, exhibited adsorption capacity of 6.49 mg · g −1 .