Deep adsorptive desulfurization of liquefied petroleum gas over Cu ion-exchanged Y zeolite

Deep desulfurization of fuels is needed to reduce sulfur oxides (SOx) emissions during combustion causing smog, global warming, and acid rain. Among petroleum-derived fuels, liquefied petroleum gas (LPG) stands out as a fuel as it causes less emissions. However, LPG may contain different sulfur compounds depending on its source. Herein, we report a copper-modified Y zeolite (Cu-Y) adsorbent for adsorptive removal of dimethyl disulfide (DMDS) and thiophene (TP) from real liquefied petroleum gas (LPG). Cu-Y zeolite was prepared by liquid phase ion-exchange (LPIE) method. Dynamic adsorption tests were conducted to investigate the performance of the adsorbent. Effects of preparation and operational conditions and regeneration on the adsorption performance were investigated. Y zeolite loaded with 7 wt% Cu2+ ion and calcined at 550 °C exhibited the highest adsorption performance. The breakthrough DMDS and TP removal capacities of Cu-Y zeolite was 117 % and 78 % higher than that of the original NaY zeolite, respectively. Cu-Y zeolite was characterized for its chemical composition, crystal structure, acidity, adsorption mechanism, surface area and morphology to reveal performance-structure relations. Regeneration studies revealed that Cu-Y adsorbent maintained its adsorption capacity without a significant loss up to 4 adsorption-regeneration cycles which makes it highly beneficial for practical applications.