海绵辅助离子液体干胶法合成ZSM-22分子筛大颗粒  

Directly Synthesis of ZSM-22 Particles by Adding Polyurethane Foam in Ionic Liquid-directed Dry-gel-conversion

作　　者：闻海萌 宋军[1] 王重庆[1] 周瑜[1] 王军[1] 

机构地区：[1]南京工业大学化学化工学院材料化学工程国家重点实验室,南京210009

出　　处：《无机材料学报》2015年第6期615-620,共6页Journal of Inorganic Materials

基　　金：国家自然科学基金(21136005;21303038;21476109)~~

摘　　要：采用海绵辅助的以离子液体作为结构导向剂的干凝胶转换法制备了宏观尺寸在毫米级的全硅ZSM-22沸石分子筛大颗粒,干凝胶的制备采用了酸环境下水解含有离子液体结构导向剂的硅源的特殊方法。结果表明,海绵辅助的离子液体干胶法对于颗粒状形貌的形成起了关键作用,在合成过程中不加入海绵或者在传统水热合成路线中加入海绵都得不到具有这种宏观颗粒形貌的ZSM-22沸石。实验系统考察了海绵的添加量、添加时间及干胶晶化时间对合成的影响,发现在微波老化结束后向合成体系添加适量的海绵,有利于合成高结晶度的颗粒状全硅ZSM-22沸石。N2O-TPD实验结果表明,所得颗粒状ZSM-22负载氧化铜后对于N2O的吸附能力优于后处理粘结剂成型的ZSM-22分子筛,说明调控沸石分子筛的宏观形貌对于沸石分子筛的吸附能力具有重要作用。Pure-silica ZSM-22 particles with millimeter size were directly synthesized by adding polyurethane foam （PU foam） in ionic liquid-directed dry-gel-conversion process, where the dry gel was prepared under the unusual acidic condition for hydrolyzing the silica precursor with 1,3-alkylimidazolium ionic liquid as the structure direct- ing agent （SDA）. Both the PU foam and the ionic liquid-directed dry-gel-conversion process played essential roles in the formation of macroscopic morphology, because only powder-like sample could be obtained in the absence of foam, and moreover, no such special morphology could be achieved on ZSM-22 zeolite prepared by the PU foam-added traditional hydrothermal synthetic route. Various synthetic parameters were systematically studied, in- eluding the influence of PU foam, adding time and adding amount of PU foam, as well as the crystallization time. Pure phase ZSM-22 particles with the highest erystallinity can be obtained by adding appropriate volume of PU foam after microwave aging. Finally, the directly synthesized ZSM-22 particles were modified by impregnating CuO2 which exhibited superior N20 adsorption property to the CuO-impregnated post-molded ZSM-22 particles with binding materials. The results indicate that there is an important influence of the macro-morphology on the adsorption performance of zeolites.

关 键 词：ZSM-22 宏观形貌控制 海绵 离子液体 干胶法 N2O程序升温脱附 

分 类 号：O613[理学—无机化学]