|題名: ||Effect of Cation Substitution on the Adsorption of Xenon on Zeolite NaY and on the Xenon-129 Chemical Shifts|
|作者: ||Liu, Shang-bin;Fung, B. M.;Yang, Tran-chin;Hong, Eng-chin;Chang, Chau-ting;Shih, Pei-chin;Tong, Fu-hsing;陳敦禮;Chen, Tun-li|
|出版者: ||American Chemical Society (ACS)|
|摘要: ||A comprehensive study of the effect of cation sub3titution on the adsorption of xenon on NaY zeolites and on 129Xec hemical shifts has been made. The cations studied include H+, alkali (Li+, K+, Rb+, Cs+), alkaline earth(Mg2+, Ca2+, Sr2+, Ba2+), and transition metal (Co2+, Ni2+, Cu2+, Zn2+), each with varied degree of exchange with Na+. The results of the adsorption isotherms were analyzed by the use of a Langmuir-type equation. It was found that the adsorption strength for the Y-zeolites follows the trend Ba > Cs 1 Rb > K 1 Sr > Ca > Na 1 Co 1 Ni 1 Li 5 Zn > Cu N H > Mg. The observed 129Xe chemical shifts of the adsorbed xenon were interpreted by a newly developed virial expansion model; an equation relating the 129Xe chemical shift and the amount of xenon atoms adsorbed per cage has been derived and used to fit the experimental data of all the
systems studied, and the results are quite satisfactory. It is suggested that the adsorption strength and the 129Xe chemical shift are dependent on the location of the cation in the supercage as well as on various interactions of the xenon atoms with each other and with the zeolite walls. The van der Waals interaction, which is determined by the polarizability of the interacting species, is the major interaction. The Coulombic interaction of the
cations plays a secondary role.
|關聯: ||Journal of physical chemistry 98(16), pp.4393-4401|