Adsorptive Removal of t-Butanethiol Using Metal Ion-exchange Y Type Zeolite under Ambient Conditions

摘要

Adsorptive removal of t-butanethiol (TBT), an odorant additive, from city gas was carried out using metal ion- exchange Y type zeolites at ambient temperature and pressure. The adsorption capacity of TBT on Na-Y under the wet gas condition was extremely low, although that under the dry gas condition was certainly higher. The adsorption capacity of TBT on silver ion-exchange Y type zeolites (Ag(Na)-Y) increased with higher silver ion- exchange ratio in Ag(Na)-Y under wet gas condition. In contrast, the adsorption capacity of TBT on Ag(Na)-Y under the dry gas condition decreased with higher silver ion-exchange ratio in Ag(Na)-Y. Formation of silver sulfide clusters in Ag(Na)-Y causes the decrease in sulfur adsorption capacity of it under the dry gas condition. The adsorption capacity of TBT on copper ion-exchange Y type zeolites (Cu(Na)-Y) increased with higher copper ion-exchange ratio in Cu(Na)-Y under the wet gas condition. In the case of Cu(Na)-Y, the decrease of TBT adsorption capacity under the dry gas condition did not occur with higher copper ion-exchange ratio in Cu(Na)-Y. The both spent samples of Ag(Na)-Y and Cu(Na)-Y were regenerated by heat treatment in air. The decrease in adsorption capacity of TBT on Cu(Na)-Y was slightly lower than that on Ag(Na)-Y.