丝光沸石硅铝比对骨架脱硅衍生介孔结构的影响  

Effect of MOR Si /Al Ratio on the Mesopore Structure Formed by Framework Desilication

作　　者：杜夏梅[1] 谷迎秋[1] 秦菲 孙月桥[1] 徐丽颖[1] 金英杰[1] 

机构地区：[1]辽宁石油化工大学,抚顺113001 [2]中石化西北油田分公司塔河采油二厂,乌鲁木齐841604

出　　处：《硅酸盐通报》2013年第10期2108-2113,2122,共7页Bulletin of the Chinese Ceramic Society

基　　金：辽宁省自然科学基金(200922180);国家自然科学基金(21171083)资助项目

摘　　要：用水热合成和铵交换法制备系列氢型丝光沸石(H-MOR),通过水热碱蚀与碱溶滤联合处理对H-MOR样品进行选择性脱硅和介孔改性。研究H-MOR骨架Si/Al比对改性沸石的介孔结构、酸性和水热稳定性的影响。N2吸附结果表明,碱处理沸石的介孔率随H-MOR硅铝比减少而增加;典型样品(n(Si)/n(Al)=9.43)具有附加介孔结构,介孔体积可达0.082 cm3/g,最可几孔径为4.6 nm;SEM观察显示,改性沸石的介孔结构源于脱硅产生的结构缺陷,晶内介孔呈无序分布;ICP和EDX分析证实,联合碱处理促进H-MOR晶体选择性脱硅(脱硅率均大于93.1%);水热稳定性和NH3-TPD数据表明,介孔改性丝光沸石较好地保持了前体的结晶性和水热稳定性,其酸性与对应H-MOR沸石相匹配。骨架硅铝比影响改性MOR沸石的介孔率,但与沸石脱硅率无相关性。Mordenite （MOR） samples with different Si/Al ratios were hydrothermally synthesized and ionexchanged into the H-form （H-MOR）. The H-MOR samples were selectively desilicated by the combination of hydrothermal alkaline etching and alkaline leaching for mesopore modification. The effect of framework Si/Al ratios on mesopore structure, acidity and hydrotherm stability was investigated for the desilicated MOR zeolites. The N2 adsorption-desorption results revealed that the mesoporosity of alkaline-treated MOR zeolites increases with the decrease in parent Si/Al ratio, and the typical sample obtained from the intact H-MOR with an Si/Al ratio around 9.43 exhibits significant mesopore structure considering the mesoporous volume of 0.082 cma/g and the most probable size of 4.6 nm. It was also observed by SEM that the mesopore structure of the modified MOR zeolites can be derived from the bulk structural defects formed by desilication but the mesopores are distributed disorderedly on the MOR crystals. The ICP and EDX results suggested that the united alkaline treatments promote MOR crystals to desilicate selectively since the degree of desilication is found to be larger than 93.1% for the H-MOR samples employed. The data on hydrothermal stability and NH3-TPD tests indicated that the well modified MOR zeolite shows the nature available both in relative crystallinity and hydrothermal stability, especially in the acidity almost equivalent to its precursor affected the mesoporosity rather than the degree H-MOR. Moreover, the Si/Al ratio in MOR framework of desilication.

关 键 词：沸石碱处理 硅铝比 介孔率 酸性 水热稳定性 

分 类 号：O643[理学—物理化学]