Characteristics and evaluation of synthetic 13X zeolite from Yunnan's natural halloysite

High purity microporous 13X zeolitic materials with octahedral microstructure were successfully synthesized by using Yunnan's natural halloysite as silica and aluminum sources through hydrothermal method in alkaline media. The effects of various factors such as the molar ratio of SiO2/Al2O3, alkalinity, crystallization time and crystallization temperature were investigated. In addition, the characteristics of its structure and porosity were studied. The optimum synthesis conditions were SiO2/Al2O3 molar ratio of 4.3, NaOH solution concentration of 2 mol/L, aging time at room temperature 12 h and crystallization temperature of 100 A degrees C/8 h. The optimum 13X zeolitic materials were fully characterized by chemical analysis, X-ray diffraction, field emission scanning electron microscopy, thermogravimetry and N-2 adsorption-desorption. The as-synthesized 13X zeolitic products exhibited high thermal stability and Langmuir surface area of up to 726 m(2)/g, value much higher than elsewhere reported.