SYNTHESIS OF NANO SIZED MESOPOROUS γ - Al۲O۳POWDER FROM DOMESTIC HAMEDAN KAOLIN

A method for producing high surface area nano-sized mesoporous alumina from inexpensive Iranian kaolin as raw material is proposed. In this method, first, kaolin was purified for purifying Kaolin, High Grade Magnetic Separation and leaching with HCl and chemical bleaching treatment by using sodium dithionite (Na ۲ S ۲O۴ ) as reducing agent in acidic media (H ۲SO ۴ ) were used. Purified kaolin was calcined. After that, Al (hydr) oxide from acid -leachates of calcined kaolin was precipitated with ammonia, in presence of polyethylene glycol. Finally, a white powder of nano-sized alumina particles was obtained after calcination. BET surface area, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) were used to characterize the sample. The resulting alumina with relatively high surface area (۲۰۱.۵۳ m ۲ g -۱ ) and narrow mean pore diameter (۶.۹۱ nm), consists of a particle size distribution ranging from ۲۲ to ۳۶ nm.

Keywords:

Nano- alumina , kaolin , Synthesis , precipitation