Phase Transformation of Zeolite P to Y and Analcime Zeolites due to Changing the Time and Temperature

In the present study, the synthesis of template free zeolite P under hydrothermal condition was investigated. The effects of parameters such as Si/Al ratios (3–45), crystallization temperatures (80–160°C), and cry (40–60？h) on the synthesis of zeolite P were studied. The phase transformation of zeolite P to two types of high crystallinity Y and analcime zeolites due to change of temperature was observed. The effect of temperature on the achievement of two different zeolite types (Y and analcime) with a constant initial synthetic composition under organic free synthesis of zeolite P was studied. The zeolitic products were characterized by X-ray diffraction, scanning electron microscopy, and IR spectroscopy techniques. 1. Introduction Zeolitic materials are microporous high-internal-surface crystalline and hydrated aluminosilicates of alkali and alkaline earth cations with an infinite open and rigid three-dimensional structure [1]. Breck et al. in 1956 reported the synthesis of “species very similar to gismodine” [2]. Later these types of zeolites were thought to belong to the harmotome-phillipsite group, which is called P zeolites [3, 4]. Zeolite P is the synthetic analogue of the GIS-type (gobbinsite-NaP1) zeolites and has a two-dimensional pore system with two intersecting 8-ring channels [5]. Zeolite P with Si/Al ratio of 1 has been described as a commercially detergent builder [6, 7]. On the other hand, the analcime structure is made up of small pores that are arranged in four-, six-, and eightfold ring. The crystal structure of analcime for the first time was determined by Taylor [8] and refined by Calleri and Ferraris [9]. Analcime may be used in selective adsorption reactions and in heterogeneous catalysis. Zeolite Y is in the faujasite (FAU) family with a framework containing double 6 rings linked through sodalite cages that generate supercages with average pore diameter of 7.4？？. There are several applications of FAU zeolites such as fluid cracking catalysts and sorbents for volatile organic removal [10]. Phase transformation processes include the transition from one structure or symmetry into another structure or symmetry, and the intermediate phases can be observed by analysis techniques. This means that from an initial gel with defined composition, one can obtain two or more pure types of zeolite depending on the conditions of crystallization such as alkalinity, crystallization temperature and time, and organic additives (template). However, such a possibility may represent a serious disadvantage in the attempt to achieve the desired group of