A REVIEW ON SYNTHESIS OF HIERARCHICAL ZEOLITES Y

Zeolites has emerged as a main heterogeneous catalyst in most chemical industries. Its diffusion limitation causes ineffective utilization of the catalyst, leading to early coking and subsequent deactivation of the zeolites. Hierarchical zeolites Y have been identified as suitable advanced material that addresses the limitations encountered with microporous zeolites in the catalytic reaction. It has an enlarged pore improved surface area and reduced channel that speed-up the reaction. The review paper focuses on two main methods of synthesizing hierarchical zeolites Y and their shortcomings. The synthesis strategies of hierarchical zeolite Y are through post-synthesis treatment (top-down) and direct synthesis with the aid of morphology modifying agents (bottom-up). However, these synthesis routes are characterized by high energy consumption and the use of expensive chemicals which are not environmentally friendly. In this review, several synthesis routes were studied and examined. The additive-free synthesis route, which involves adjustment of crystallization parameters and additional aging steps, was economically and ecologically friendly. Hierarchical zeolites Y have been extensively used in industrial applications due to their enhanced intra-crystalline diffusion and improved catalytic properties. Keywords: Zeolite Y, Hierarchical zeolite, Top-down, Bottom-up