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

Abstract

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/1butene purification and that (2) Ag-Y maintained stability against H 2 S.

Mesoporous-molecular-sieve-supported Polymer Sorbents for Removing H2S from Hydrogen Gas Streams

“…Some activated carbons have also been reported as adsorbents for removing H 2 S from moist air (80% humidity) or dry air at low temperature on the basis of the adsorption/oxidation in the presence of O 2 [21][22][23]. Other compounds such as Cu + -or Ag + -ion-exchanged Y zeolite have also been used for H 2 S removal by formation of Cu 2 S or Ag 2 S [24,25]. Although some of these adsorbents achieved good performances for removing H 2 S, all these materials have at least one major problem, such as low separation efficiency, low selectivity, high operation cost, low sorption/desorption rate, higher H 2 S level after sorption, higher loss of hydrogen gas, etc., which limits their industrial application.…”

Highly selective sulfonated polyethersulfone (SPES)-based membranes with transition metal counterions for hydrogen recovery and natural gas separation

“…The interaction of gases with the double bond and transition metal ions has been studied widely [7][8][9][10][11]. The transition metal ions can form the normal -bond to carbon and, moreover, the unique characteristics of their d orbital can make them form bonds with unsaturated hydrocarbons in a nonclassical manner.…”

“…The transition metal ions can form the normal -bond to carbon and, moreover, the unique characteristics of their d orbital can make them form bonds with unsaturated hydrocarbons in a nonclassical manner. For example, the work done by Takahashi et al [7,8] applied Ag ion-exchanged and Cu ion-exchanged zeolites for diene/olefin separation and exhibited excellent purification characteristics attributed to strong -complexation bonds with CO and C 2 H 4 . Kanazawa's work [9] showed that C 2 H 4 gas was barely adsorbed by zeolite ZSM5 because the molecules are too small; however, Ag ion-exchanged zeolite enabled C 2 H 4 adsorption and, furthermore, the adsorption rate did not fall even at a high temperature of 500 • C or after 3.6 × 10 5 s (100 h) durability testing.…”

The effect of metal ions in MNaY-zeolites for the adsorptive removal of tetrahydrothiophene

“…Silver, copper, cobalt, and nickel species in MNa-Y can be present as Ag + [31], Cu 2+ [32], Co 2+ [33], and Ni 2+ [34], respectively. In the case of CuNa-Y, the auto reduction from Cu 2+ to Cu + has been reported to occur during heat treatment above 350 o C [35].…”