Adsorptive separation of dimethyl disulfide from liquefied petroleum gas by different zeolites and selectivity study via FT-IR

• Dimethyl disulfide in liquefied petroleum gas was adsorbed by the modified zeolites.
• The adsorption mechanism was studied by FT-IR spectroscopy.
• The regenerability of adsorbent Ag2O/NaY was also studied.

The removal of dimethyl disulfide from model liquefied petroleum gas using metal salt impregnated zeolite as the adsorbent was studied in a fixed-bed adsorption equipment. Effects of different carrier, metal iron species and content of active component, mass space velocity, temperature, as well as adsorption selectivity and regeneration performance were all investigated by performing the breakthrough experiment. Among all these adsorbents, 5 wt.%Ag2O/NaY showed the highest breakthrough sulfur capacity. The adsorption selectivity of Ag2O/NaY was studied by the infrared spectra. It was found that the direct S–Ag(I) interaction was the essential reason for the evidently improved adsorption ability and selectivity of Ag2O/NaY for removing disulfide from solutions containing olefin. Regeneration study indicated that the saturated adsorbent was regenerated under the temperature of 550 °C for 8 h in the air atmosphere. After five times regeneration, the adsorbent Ag2O/NaY still shows high breakthrough sulfur capacity.

Adsorbent Ag2O/NaY which was prepared by equivalent-volume impregnation method was selected and used for separation of dimethyl disulfide from model liquefied petroleum gas. The separation ability of NaY and Ag2O/NaY for removing dimethyl disulfide from model liquefied petroleum gas with or without 1-hexene was compared. The adsorption strength of dimethyl disulfide on NaY and Ag2O/NaY as well as the competitive adsorption of dimethyl disulfide and olefin on NaY and Ag2O/NaY were investigated detailedly by FT-IR spectroscopy.Figure optionsDownload as PowerPoint slide