几种过渡金属离子改性的4A分子筛结构性能

Structural properties of 4A molecular sieve modified by transition metal ions

4A分子筛金属改性能够有效地提高分子筛在吸附分离等方面的作用,但对不同种类过渡金属改性4A分子筛的系统研究鲜有报道。文中将4种不同种类的过渡金属镍、钴、铜、铁通过离子交换法交换到4A分子筛中,结果发现Cu离子和Fe离子改性后分子筛结构发生破坏,Ni离子、Co离子可以作为平衡阳离子交换到4A分子筛中,且分子筛比表面积增大。由此可推测,4A分子筛经Ni离子、Co离子交换改性后,Ni^(2+)、Co^(2+)作为分子筛的平衡阳离子能与N_(2)形成反馈π键,加快对N_(2)的吸附速率,从而为混合气体中N_(2)的吸附分离提供一定理论基础。

The 4A molecular sieve modified by metal ions can effectively improve its performance in adsorption and separation,but there are few reports on the modification of 4A molecular sieve by different transition metals.Four different kinds of transition metals(nickel,cobalt,copper and iron)were exchanged into 4A zeolite by ion exchange method.The results show that the structure of 4A molecular sieve modified by Cu ions and Fe ions are destroyed.Ni ions and Co ions can be exchanged into 4A molecular sieve as equilibrium cations.The BET test shows that the specific surface area of the molecular sieve modified by Ni ions and Co ions are increased.It can be inferred that Ni^(2+) and Co^(2+),as the equilibrium cation of 4A molecular sieve,can form feedbackπbond with N_(2) and accelerate the adsorption rate of N_(2).It provides a theoretical basis for the adsorption and separation of N_(2) in the mixed gas.