摘要
使用Materials Studio软件包中的CASTEP模块对斜发沸石(Si与Al的摩尔比为4)孔道中的Na+迁徙轨迹、水合Na斜发沸石孔道中Na+与水分子的构象、以及孔道中K+-Na+的离子交换过程进行了模拟研究。结果表明:在含有Na+的斜发沸石孔道中,由于八元环骨架中的Al/Si取代位的局部结构形变所引起晶格能量的扰动,导致Na+被吸引在该取代位;Al原子在孔道中的分布决定着孔道中Na+的分布,且孔道中的H2O有将Na+固定在沸石骨架上的趋势;由于沸石孔道中不同离子间和孔道中的阳离子与骨架上的原子间的相互作用,导致沸石孔道中K+和Na+发生离子交换,证明了斜发沸石具有优先选择K+的特性,得出的K-斜发沸石的结构参数与文献吻合较好。
The diffusion trajectory of Na＋,the configuration of Na＋ and water molecules in hydrated clinoptilolite,and the Na＋/K＋ ion exchange process in the channel of clinoptilolite（the mole ratio of Si to Al is 4） were simulated using the Materials Studio software package＇s CASTEP module.The results show that a perturbation of the lattice energy caused by the local deformation of the structure of the Al/Si substitution on the eight-membered ring framework results in the Al/Si substitution attracting the Na＋.The distribution of the Al sites on the extra-framework site determines the distribution of the Na＋ in the channel.The water molecule suppresses the mobility of Na＋ and stabilizes the Na＋ on the zeolite framework.The interaction between ions in the channel and the interaction between the ions and the zeolite framework lead to the K＋-Na＋ ion-exchange process in the channel,which means that clinoptilolite has selectivity to K＋.The structure parameters of the final K-clinoptilolite agree well with the reference.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2009年第10期1724-1729,共6页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金(20806019)
"十一五"国家科技支撑计划课题(2006BAB03A10)
河北省自然科学基金(B2007000008)资助项目
关键词
分子动力学模拟
斜发沸石
水合
离子交换
molecular dynamics simulation
clinoptilolite
hydration
ion-exchange
