Preparation of Pseudo-boehmite and γ-Al2O3 by Polyaluminum Chloride II -Surfactant Influences

Pseudo-boehmite and its derivative gamma-Al2O3 were prepared from polyaluminum chloride by sol-gel method. The samples were characterized by XRD, TEM and N-2, adsorption-desorption techniques. Effects of pH value, preparation temperature and species of pluronic surfactants on the physical properties of pseudo-boehmite were investigated. Results show that alumina hydrate is mainly pseudo-boehmite prepared at pH value near 8.5 and at temperature value near 70 degrees C. With the increase of pluronic surfactants molecular weight, the degree of crystallinity of pseudo-boehmite and its derivative gamma-Al2O3 increases. It is proved that phases of products do not change after adding the pluronic surfactants L64, L65 and F68. The gamma-Al2O3 phases are obtained after 6 hours calcination of the pseudo-boehmite at 500 degrees C. L65 is the most suitable for increasing surface area of gamma-Al2O3, surface area of 231 m(2).g(-1), pore volume of 0.28 cm(3).g(-1) and pore size of 4.52 nm was obtained.