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摘要
The Li-ISX zeolite was synthesized via ion exchange method with Na-LSX zeolite as a starting material, and its structural properties were characterized using FT-IR, SEM and TG-DSC techniques. The results showed that the water adsorption capacity of Li-LSX was enhanced but its thermal stability was decreased compared with that of Na-LSX. Meanwhile, combined with in situ HTXRD patterns, the parallel exothermal DSC profiles demonstrated that cationic radius and adsorbed water in FAU framework had remarkable influence on the thermal stability of Li-LSX and Na-LSX. In addition, the amount of N-2 adsorbed on Li-ISX at room temperature (298 K) was around 19.76 g/cm(3), which was higher than that of Na-LSX (5.42 g/cm(3)). Whereas, N-2 adsorption-desorption isotherm of Li-LSX at 77 K showed the BET surface area (778.0 m(2)/g) and relevant pore volume (0.40 cm(3)/g) were higher than those of Na-LSX (622.5 m(2)/g and 0.33 cm(3)/g), respectively. These results suggested that the N-2 adsorption capacities of LSX zeolites at 77 K could be determined mainly according to their porosity; while, at 298 K, the adsorption capacities depended on both the N-2-cation interaction and their porosity. Therefore, it was concluded that the charge density and cationic radius (Na+ and Li+) had a remarkable influence on their adsorption performance, structural parameters (textural parameters) and their stability.
- 出版日期2015-1-15
- 单位北京工业大学
