Selective oxidation of hydrogen sulfide to sulfur over activated carbon-supported metal oxides

Abstract

The selective oxidation of hydrogen sulfide (H2S) to sulfur on activated carbon-supported metal oxide sorbents (M/AC) was investigated for hot fuel gas desulfurization. Various M/AC sorbents loaded with 1wt.% metal oxide were separately prepared by pore volume impregnation and their breakthrough capacity was examined. The results showed that the breakthrough capacity of different sorbents can be placed in the following order: Mn/AC>Cu/AC>Fe/AC>Ce/AC>Co/AC>V/AC. The metal oxides loaded on the M/AC surface catalyze the reaction between hydrogen sulfide and oxygen to form element sulfur; the activated carbon, as an adsorbent, can adsorb and store the element sulfur in its pore passage. The DTG analysis and determination of forms of sulfur confirmed that the main product of the catalytic oxidation of hydrogen sulfide was elemental sulfur. The regeneration of exhausted sorbents was carried out using hot gas N2 and H2O desorption methods at temperature 500°C. The breakthrough capacity of the sorbent was mostly recovered after regeneration. The mechanism of the catalytic oxidation of H2S on M/AC sorbent was also discussed.