镧改性的CuHY分子筛中铜离子的分布及其对吸附脱硫性能的影响  

Distribution of Cu Ions in Lanthanum-Modified CuHY Zeolite and Its Influence on Adsorption Desulfurization Performance

作　　者：范闽光[1] 李斌[1] 张飞跃[1] 方金龙[1] 李望良[2] 邢建民[2] 刘自力[1] 

机构地区：[1]广西大学化学化工学院,广西南宁530004 [2]中国科学院过程工程研究所,北京100871

出　　处：《催化学报》2009年第10期1041-1048,共8页

基　　金：国家重点基础研究发展计划(973计划;2006CB202507);广西省自然科学基金(0640004);广西研究生教育创新计划(2008105930817D013)

摘　　要：在氮气气氛下采用等体积浸渍法制备了载Cu的HY和LaHY分子筛.用X射线衍射(XRD)、N2吸附、氨程序升温脱附和X射线光电子能谱对分子筛进行了表征.通过多晶XRD确定了Cu2+离子在Y型分子筛笼内的结构与分布,并测定了分子筛在含二苯并噻吩(DBT)的模拟柴油中的吸附脱硫性能.结果表明,前驱体CuCl2中的大部分Cu物种与HY和LaHY分子筛进行了离子交换.对于La3+改性的CuHY分子筛(CuLaHY),进入分子筛超笼中的Cu2+离子与骨架氧和水分子配位,牢固地定位于Y型分子筛超笼的SII及SIII位;对于CuHY分子筛,超笼中的Cu2+离子只接近于SII及SIII位.极少部分CuCl分子高度分散在分子筛笼内,没有定位.处于超笼中SII及SIII位的Cu2+离子对模拟柴油中的DBT分子具有吸附作用,是吸附脱硫的活性中心.CuLaHY分子筛的吸附脱硫性能优于CuHY分子筛.当模拟柴油中含有萘时,萘与DBT分子会产生竞争吸附.The Cu-loaded CuHY and CuLaHY zeolites were prepared by an incipient wetness method under nitrogen gas atmosphere. The samples were characterized by X-ray diffraction （XRD）, N2 adsorption, NH3 temperature-programmed desorption, and X-ray photoelectron spectroscopy. The crystalline structure and the distribution of Cu^2＋ cations in the cages of Y zeolite were determined by XRD. The adsorption desulfurization performance of the zeolites was investigated for model diesel containing dibenzothiophene （DBT）. The results showed that most of Cu species from the precursor CuCl2 was ion-exchanged with the HY and LaHY zeolites. For the La^3＋-modified CuHY zeolite （CuLaHY）, the Cu^2＋ cations entering the supercages of the zeolite coordinated with both skeleton-oxygen atoms and water molecules, and thus being firmly situated at the sites SⅡ and SⅢ in the supercages. For the CuHY zeolite, however, Cu^2＋ cations entering the supercages were only near the sites SⅡ and SⅢ in the supercages. A very small percentage of CuCl molecules was highly scattered in the cages of the Y zeolite, with no definite position. The Cu^2＋ cations at the sites SⅡ and SⅢ in the supercages adsorbed DBT molecules in the model diesel were the centers of adsorption desulfurization. The desulfurization capacity of the CuLaHY zeolite was better as compared with the CuHY zeolite. However, naphthalene molecules will result in competitive adsorption with DBT molecules if there are naphthalene molecules in the model diesel.

关 键 词：HY分子筛 铜 镧 吸附剂 修饰 二苯并噻吩 吸附脱硫 

分 类 号：TE621[石油与天然气工程—油气加工工程]