Hydrothermal synthesis of hierarchical micron flower-like γ-AlOOH and γ-Al2O3 superstructures from oil shale ash

The hierarchical micron flower-like gamma-AlOOH and gamma-Al2O3 superstructures were synthesized using oil shale ash (OSA) as a new raw material. In order to prepare the better quality alumina with uniform morphology, the effects of ethanol and surfactant CTAB on the formation of alumina particles were investigated and the formation mechanism of flower-like composite particles was also discussed. The structural and morphological properties of the uncalcined and calcined powders were characterized by X-ray diffractometer (XRD), Scanning electron microscope (SEM), Brunauer Emmett Teller (BET) and Fourier transform infrared (FT-IR). The results indicated that uniform flower-like gamma-AlOOH and gamma-Al2O3 assembled by nanosheets which thickness is less than 100 nm were prepared. After calcined at 600 degrees C, morphology of the flower-like superstructure was maintained perfectly. The results obtained in this work prove that the oil shale ash can be used for production of hierarchical superstructures alumina and open a new way for comprehensive application of OSA. (C) 2011 Elsevier B.V. All rights reserved.