关键词: LEV分子筛, 纳米晶体, 简易合成, 酸性, 孔结构性质

Abstract: In this contribution, we reported facile preparation of nano-sized LEV molecular sieve with various n（SiO₂）/n（Al₂O₃） by using isopropyltrimethylammonium as structure-directing agent for the first time. The effect of aluminum sources, alkali cations, initial n（SiO₂）/n（Al₂O₃）and alkalinity on the products outcome was investigated. It turns out that sodium aluminate and sodium hydroxide are beneficial to the crystallization of nano-sized LEV molecular sieve. LEV molecular sieve could be obtained with initial n（SiO₂）/n（Al₂O₃） ranging from 20 to 150, by modulating the alkalinity of the initial gel. The total acid amount drops with the increasing of n（SiO₂）/n（Al₂O₃）, while the acid strength enhances. The nano-sized LEV molecular sieve has high specific area and micropore volume. Moreover, the total pore volume exceeds 1.0 cm³/g, which is extremely high. This type of molecular sieve material is endowed with high application potential in adsorptive separation and selective conversion of organic molecules, thanks to its nano-sized dimension, strong acidity as well as high surface area and pore volume.

Key words: LEV molecular sieve, nanosized crystal, facile synthesis, acidity, textural property