In the last decade, exploration of transition alumina phases with good
adsorption properties has attracted a great research interest from both a
fundamental and a practical point of view. The transition phases of alumina
are metastable polymorphs of aluminum oxide formed through the thermal
dehydration of aluminum trihydroxide and aluminum oxyhydroxide. Powder X-ray
diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR),
scanning electron microscopy (SEM) and low-temperature nitrogen absorption
studies were employed to trace the formation of the transition phases of
alumina. In this work transition alumina powders were synthesized starting
from sodium aluminate solution prepared from Bayer liquor. The
neutralization of sodium aluminate solution was performed with the use of
sulphuric acid, while glucose was added in the starting solution. In this
way, the single phase nanocrystalline boehmite was obtained. As-synthesized
boehmite powders have high surface area (above 360 m2/g) and the average
crystallite size less than 5 nm. The results showed that the properties of
the powders (structure, morphology) are strongly influenced by the initial
pH value of sodium aluminate solution, as well as by the duration of
neutralization step.
Effect of process parameters on the morphology and adsorption properties of nanocrystalline boehmite