Adsorptive removal of tert-butylmercaptan and tetrahydrothiophene using microporous molecular sieve ETS-10

The adsorptive removal of tert-butylmercaptan (TBM) and tetrahydrothiophene (THT) in methane gas using microporous molecular sieve ETS-10 was investigated at an ambient temperature and atmospheric pressure. Na,K-ETS-10 and Cu-exchanged Na,K-ETS-10 (Cu-ETS-10) were characterized by X-ray diffractometer (XRD) for the crystalline phase, X-ray fluorescence (XRF) analyzer for the chemical composition, and nitrogen adsorption-isotherm measurement for the BET surface area and porosity, respectively. Posterior to its treatment at 723 K in He atmosphere for 2 h, the Cu(II) in Cu-ETS-10 could be partially autoreduced to Cu(I), which was confirmed by X-ray photoelectron spectroscopy (XPS). The preferential adsorption of THT over TBM on Na,K-ETS-10 and the concurrent adsorption of TBM and THT on Cu-ETS-10 were achieved, which could be explained by the uptake curve in the binary component adsorption, the temperature-programmed desorption, and the apparent activation energy for desorption. The breakthrough sulfur adsorption capacity for both TBM and THT was attained to 2.50 mmol S/g on Cu-ETS-10-0.1(4). This markedly high breakthrough sulfur adsorption capacity on Cu-ETS-10 is unprecedented in removing organic sulfur compounds from fuel gas by adsorption on zeolites.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ High adsorption selectivity for THT over TBM on Na,K-ETS-10 is achieved. ▶ Introduction of Cu in Na,K-ETS-10 leads to concurrent adsorption of THT and TBM. ▶ Breakthrough adsorption capacity for THT and TBM on Cu-ETS-10(4) is 2.50 mmol S/g.