Preparation And Properties Of Nano/micro Structure Alumina Composite Materials

In recent years, the preparation of nano/micro powder materials with well-controlled morphology has increased great attention. By a variety of methods,different types of nano/micro powder materials had been prepared. In this paper,nano/micro boehmite, γ-alumina and γ-alumina/anatase composites materials wereprepared successfully by hydrothermal synthesis and hydrothermal-sol method. Inaddition, the synthesis conditions of experiment were discussed systematically andthe structure and performance of as-obtained products were characterized in detail.With oil shale ash as a raw material, flower-like3D micron boehmite and gammaalumina powders were prepared in this paper under hydrothermal condition. Thesurfactant cetyltrimethylammonium bromide(CTAB) was added to adjust the crystalgrowth and to assure the crystalline self-assembly in an ordered way, so as to achieveproducts with prefer morphology. The absolute ethanol was added to control thereaction rate. Micro flower-like gamma alumina material obtained in this experimenthas meso-porous structure and may have promising application in the filed ofadsorption and catalytic. The experiment provides a new way to effective utilizationof oil shale ash.Besides, under hydrothermal process, boehmite products with differentmorphologies were prepared by adjusting the pH value of the initial solution. Themorphology of products vary from hollow microsphere, core-shell structure,nanocubic, wheat-grain like to irregular nanoparticles. The influence of the pH valueon the morphology and performance of products were illustrated. The obtainedboehmite products have large specific surface areas and plenty meso-porousstructures. The products are found to be effective adsorbents for the removal ofCongo red and are expected to be used as adsorbent.Micro γ-alumina/anatase microspheres were prepared by hydrothermal-sol method. The influence of calcination temperature and the amount of tetrabutyl titanate(TBOT) on the morphology and performance of products had been discussed. Theoptimum calcination temperature was600℃in this experiment. The experimentresult revealed that the surface area and the porosity ratio of the products reduced,while the intensity of anatase phase increased with increasing the amount of TBOT.Thus, two factors that the intensity of anatase phase and specific surface area shouldbe considered in the practical application. The composite materials may haveexcellent photocatalytic performance and are expected to be used in treatment oforganic wastewater.