Effect of template type and template/silica mole ratio on the crystallinity of synthesized nanosized ZSM-5

The crystallinity of nanosized ZSM-5 zeolite from precursors mixtures containing different template types, tetramethylammonium hydroxide, tetraethyl ammonium hydroxide, tetrapropylammonium hydroxide and tetrabutylammonium hydroxide, and different template/ silica mole ratios, 0.215, 0.322, 0.43 and 0.537, has been studied. The produced samples were investigated using XRD, SEM, FT-IR and BET surface area measurements. Physicochemical investigations showed that the obtained products by different type of templates and different template/silica mole ratios were ZSM-5 phase. The as-synthesized ZSM-5 sample prepared by using tetrapropyl ammonium hydroxide template and 0.215 template/silica mole ratio at 230 degrees C for 45 h had the highest crystallinity. It was found that the average crystallite size increased in the following order; tetramethyl < tetrabutyl < tetraethyl < tetrapropyl and surface area increased in the following order: TMAOH < TEAOH < TBAOH < TPAOH. By increasing template/silica mole ratios from 0.215 to 0.537 the surface area decreased and average crystallite size increased. (c) 2006 Elsevier B.V. All rights reserved.