沸石
阳离子交换容量
化学
离子交换
硅酸铝
铵
盐(化学)
无机化学
稀释
离子
吸收能力
分析化学(期刊)
物理化学
热力学
化学工程
色谱法
有机化学
催化作用
地质学
物理
土壤科学
工程类
土壤水分
出处
期刊:Elsevier eBooks
[Elsevier]
日期:2001-01-01
卷期号:: 67-68
标识
DOI:10.1016/b978-044450703-7/50112-5
摘要
This chapter explains the ion exchange capacity in zeolites. In a traditional aluminosilicate zeolite the source of the ion exchange capacity is the extent of isomorphous substitution of Al for Si in the tetrahedral framework. The theoretical exchange capacity thus can be derived from the elemental composition. To estimate the CEC (cation exchange capacity, meq/g) in a natural zeolite it is usual to observe the uptake of the ammonium cation at room temperature when equilibrium conditions are known to have been attained in the presence of a IM ammonium salt solution. When synthetic materials are to be characterized, prior careful elemental analysis will provide the expected, theoretical cation capacity. The most sensitive analytical technique available is to use radioisotopes to prelabel the A cation and follow its replacement by increase in solution activity with time. (Isotope dilution technique). This will be possible for the as synthesized cations Na, K, Rb, Cs, Ca, Sr and Ba. In the absence of radiochemical facilities, flame photometry, atomic absorption are perfectly adequate.
科研通智能强力驱动
Strongly Powered by AbleSci AI