The effect of the process condition on synthesis amorphous silica alumina from metakaolin on pore structure and crystallinity of product

Department of Chemical Engineering, Bandung State Polytechnic, Jl. Gegerkalong Hilir, ds.Ciwaruga, Bandung 40012, Indonesia

Corresponding author: endang.srirahayu@polban.ac.id

Abstract

The objective of the research to study the effect of amorphous silica alumina (ASA) synthesis condition on pore structure and crystallinity. Synthesis of ASA was done by co-precipitation method, that preceded by neutralization to form a sol phase, followed by introducing a silica solution, and then aging to form an amorphous phase. Alumina solution is resulted by leaching of metakaolin from kaolin Belitung, Indonesia. The use of alumina source from this kaolin is a novelty method. Process conditions synthesis of ASA were varied on Si /Al ratio, time of neutralization and time of aging. While, a pH and temperature of neutralization are as independent process variable, of 7-8 and 50-55 °C, respectively. Characterization of ASA was performed using XRD, surface area and pore analyzer. The increasing of Si/Al ratio in starting material affects on the surface area of ASA, as well as with aging time. The best product of ASA with a specific surface area of 510 m²/g, average pore diameter of 85 Å, a total pore volume of 1.1 mL/g, and an amorphous phase of 53%-mass were observed.