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．
The states of aluminum in zeolites β were investigated with FTIR spectroscopy. Threekinds of aluminium, framework, nonframework and transient state aluminium, were detected intemplate-removed zeolite β. The states of aluminium in our samples strongly depends on thenature of the compensating cation, consistent with Brougeat-Lami et al's conclusion. But somenew assignments of aluminum species and new opinions about the states of aluminum and theirtransformation are proposed. From the experimental results, we suggest that, the distortion andtension of zeolite lattice occur when protons, which possess high electron affinity , are located atcationic sites, leading to the breakage of Al-- O bond and the removal of aluminium. The distortionis released when H+ is replaced by other cations (e.g. Na+ ) so that transient state aluminium cango back into the framework, while the cationic nonframework aluminium species enter the solutionupon the ion-exchange.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
1998年第2期169-173,共5页
Acta Physico-Chimica Sinica
关键词
Β沸石
铝状态
归属
FTIR
沸石
Zeolite β, State and assignment of aluminium, FTIR
