物理化学学报 >> 1998, Vol. 14 >> Issue (02): 169-172.doi: 10.3866/PKU.WHXB19980214

研究论文 上一篇    下一篇

β 沸石中铝的状态及归属

杨春, 须沁华   

  1. 南京大学化学系,南京 210093
  • 收稿日期:1997-06-13 修回日期:1997-09-22 发布日期:1998-02-15
  • 通讯作者: 须沁华

States and Assignment of Aluminium in Zeolite β

Yang Chun, Xu Qin-Hua   

  1. Department of Chemistry,Nanjing University,Nanjing 210093
  • Received:1997-06-13 Revised:1997-09-22 Published:1998-02-15
  • Contact: Xu Qin-Hua

摘要:

用FTIR方法对β沸石中铝的状态进行了研究.结果表明,在脱除模板剂的β沸石中存在着三种状态的铝,即骨架铝、非骨架铝和过度态铝.铝的存在状态与平衡阳离子的性质密切相关,当平衡阳离子为高电子亲和性的H+时,β沸石的骨架发生扭曲而具有较大的张力,使得Al-O键断裂,铝经过渡态移出骨架,成为非骨架铝.当H+被Na+等离子取代后,骨架形变得以缓解,过渡态铝重又恢复骨架四面体配位,而阳离子态的非骨架铝物种则被交换进入溶液.

关键词: β沸石, 铝的状态及归属, FTIR

Abstract:

The states of aluminum in zeolites β were investigated with FTIR spectroscopy. Three kinds of aluminium, framework, nonframework and transient state aluminium, were detected in template-removed zeolite β. The states of aluminium in our samples strongly depends on the nature of the compensating cation, consistent with Brougeat-Lami et al's conclusion. But some new assignments of aluminum species and new opinions about the states of aluminum and their transformation are proposed. From the experimental results, we suggest that, the distortion and tension of zeolite lattice occur when protons, which possess high electron affinity , are located at cationic sites, leading to the breakage of Al-- O bond and the removal of aluminium. The distortion is released when H+ is replaced by other cations (e.g. Na+ ) so that transient state aluminium can go back into the framework, while the cationic nonframework aluminium species enter the solution upon the ion-exchange.

Key words: Zeolite β, State and assignment of aluminium, FTIR