Effect of particle size on the hydrothermal stability of zeolite beta

The effects of particle size, steam pressure, temperature, and duration on the hydrothermal stability of zeolite beta were studied using the Taguchi orthogonal design. The particle size, crystallinity, textural properties, acidity, and framework structure of the zeolite beta were compared before and after hydrothermal treatment. The results showed that the hydrothermal stability of zeolite beta increased with particle size decrease, and decreased with increase of steam pressure and temperature. No significant changes in particle sizes and morphologies were observed for zeolites with particle sizes between 100 nm and 500 nm, while an obvious aggregation was identified for the nano-sized sample. The total surface areas and acidity of all treated zeolites were reduced by hydrothermal treatment. After hydrothermal treatment, obvious realumination was observed for all zeolites. (c) 2006 Elsevier Inc. All rights reserved.