Nickel Sulfides Decorated SiC Foam for the Low Temperature Conversion of H(2)S into Elemental Sulfur

The selective oxidation of H(2)S to elemental sulfur was carried out on a NiS(2)/SiC(foam) catalyst under reaction temperatures between 40 and 80 °C using highly H(2)S enriched effluents (from 0.5 to 1 vol.%). The amphiphilic properties of SiC foam provide an ideal support for the anchoring and growth of a NiS(2) active phase. The NiS(2)/SiC composite was employed for the desulfurization of highly H(2)S-rich effluents under discontinuous mode with almost complete H(2)S conversion (nearly 100% for 0.5 and 1 vol.% of H(2)S) and sulfur selectivity (from 99.6 to 96.0% at 40 and 80 °C, respectively), together with an unprecedented sulfur-storage capacity. Solid sulfur was produced in large aggregates at the outer catalyst surface and relatively high H(2)S conversion was maintained until sulfur deposits reached 140 wt.% of the starting catalyst weight. Notably, the spent NiS(2)/SiC(foam) catalyst fully recovered its pristine performance (H(2)S conversion, selectivity and sulfur-storage capacity) upon regeneration at 320 °C under He, and thus, it is destined to become a benchmark desulfurization system for operating in discontinuous mode.