Influence of Ag Content and H₂S Exposure on 1,3-Butadiene/1-Butene Adsorption by Ag Ion-Exchanged Y-Zeolites (Ag−Y)

It was found earlier in our laboratories that Ag ion-exchanged zeolite was capable of purifying 1-butene by selective adsorbing trace amounts of 1,3-butadiene. The effect of Ag content in Ag ion-exchanged Y-zeolite (Ag−Y) on 1,3-butadiene/1-butene adsorption was investigated using Ag−Y with different Si/Al ratios and different degrees of Ag + /Na + exchange (AgNa−Y). AgNa−Y with a Ag content of 34 Ag/u.c. exhibited excellent adsorption performance in terms of both separation factor and uptake rate. The influence of H 2 S exposure on sorbent performance was also examined. Although both 1,3-butadiene and 1-butene adsorption amounts were decreased by H 2 S exposure, the separation factors remained well over 100, which were still good for purification. XPS analysis revealed that Ag + in Ag−Y reacted with H 2 S to form Ag 2 S. The high selectivity for butadiene over 1-butene was indicative of the π-complexation ability of Ag 2 S. This work demonstrated that (1) an intermediate silver loading was the best for 1,3-butadiene/1-butene purification and that (2) Ag−Y maintained stability against H 2 S.