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Adsorptive removal of tetrahydrothiophene (THT) and tert-butylmercaptan (TBM) using Na-Y and AgNa-Y zeolites for fuel cell applications

Paper ID Volume ID Publish Year Pages File Format Full-Text
43200 45958 2008 8 PDF Available
Title
Adsorptive removal of tetrahydrothiophene (THT) and tert-butylmercaptan (TBM) using Na-Y and AgNa-Y zeolites for fuel cell applications
Abstract

Adsorptive removal of tetrahydrothiophene (THT) and tert-butylmercaptan (TBM) that are widely used sulfur odorants in pipeline natural gas was studied using AgNa-Y zeolites at ambient temperature and atmospheric pressure. The AgNa-Y were obtained via Ag+-exchange with Na+ of Na-Y at various exchange levels, and the contributions of formed adsorption sites (Ag+, Na+, Ag0, H+, and Ag2O) in the THT and TBM adsorption uptake and selectivity were characterized. THT adsorption strength on these sites followed an order of Ag+ > Na+ ∼ Ag0 > H+ > Ag2O. The adsorption strength of THT on Na+ sites was sufficiently high, thus an increase in the Ag+-exchange level did not lead to a notable increase in the breakthrough THT uptake. Differently, adsorption of TBM on Na+ sites was weak, whereas that on Ag+ sites was strong. This resulted in a marked increase in the breakthrough TBM uptake with an increase in the Ag+-exchange level, showing an order of magnitude higher uptake on AgNa-Y compared with that on Na-Y. Noticeably, the adsorption strength of THT on these adsorption sites was higher than that of TBM. This resulted in an almost 100% adsorption selectivity for THT over TBM, when these two sulfur species coexisted in the feed stream.

Graphical abstractAdsorptive removal of tetrahydrothiophene (THT) and tert-butylmercaptan (TBM) was studied using AgNa-Y zeolites. THT adsorption strength on these sites follow an order of Ag+ > Na+ ∼ Ag0 > H+ > Ag2O. The adsorption strength of THT on the Na+ sites was sufficiently high, and an increase in the Ag+-exchange level did not lead to a notable increase in the breakthrough THT uptake. Differently, adsorption of TBM on the Na+ sites was weak, whereas that on the Ag+ site was strong. This resulted in a marked increase in the breakthrough TBM adsorption uptake with an increase in the Ag+-exchange level, showing an order of magnitude higher uptake on AgNa-Y compared with that on Na-Y. Noticeably, an almost 100% adsorption selectivity for THT over TBM was observed over AgNa-Y when these two sulfur species coexisted in the feed stream. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Adsorption; Desulfurization; Tetrahydrothiophene; tert-Butlymercaptan; Ag-Y; Na-Y; Fuel cell
First Page Preview
Adsorptive removal of tetrahydrothiophene (THT) and tert-butylmercaptan (TBM) using Na-Y and AgNa-Y zeolites for fuel cell applications
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 334, Issues 1–2, 1 January 2008, Pages 129–136
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis