Synthesis and characterization of ZSM-5 zeolite from serpentine

A serpentine mineral was treated in hydrochloric acid solution to obtain amorphous silica with high surface area. The highly porous silica residue was used as a silica source for the synthesis of zeolite ZSM-5 by hydrothermal method. The syntheses were conducted with variations in the composition of aNa2O·bAl2O3·cSiO2·dH2O·e(TPA)2O, the reaction temperature of 125 to 185 °C, and the reaction time of 12 to 48 h. An optimum condition for the synthesis was achieved with a composition of a=11.7, b=1, c=90, d=3510, and e=10.8 at 170 °C for 24 h, followed by calcinations at 600 °C. The crystallinity degree of the prepared zeolites was in 90% to 97% and the highest was obtained at SiO2/Al2O3 molar ratio of 90 at which its average particle size and surface area were 1.2 μm and 357 m2/g, respectively.