Huiling Fan

The low sulfur selectivity of Fe-based H2S-selective catalytic oxidation catalysts is still a problem, especially at a high O2 content. This is alleviated here through anchoring FeO x nanoclusters on UiO-66 via the formation of Fe-O-Zr bonds. The introduced FeO x species exist in the form of FeIII and FeII. Therein the FeIII-O species are the predominant active sites for H2S-oxidation. The formed Fe-O-Zr bonds strengthen the redox cycle of FeIII/FeII through promoting electron transfer from Fe to Zr. The FeII-O species can activate molecular oxygen to oxidize H2S into elemental S, which accelerates the formation rate of atomic S, hindering its further oxidation into SO2. The combination of these factors empowers the catalysts, enabling 100% H2S conversion and 98.2% sulfur yield. The catalyst also has satisfactory stability with the sulfur selectivity only decreasing from 98.2% to 91.3% after the reaction going on 50 h. The decreased sulfur selectivity might be caused by the deterioration of pores and the deposition of elemental S on the surface. The former hinders the diffusion of sulfur oligomers timely from pores to the gas phase, while the latter is suspected to capture electrons to promote its further reaction with molecular oxygen.

Solid waste Co-containing adsorbents are considered to be used for the hydrotreating process. Herein, Cobalt-based waste materials from the low-temperature desulfurization process were used as organic sulfur hydrotreating catalysts. Physicochemical properties of waste adsorbents were characterized and the performance for COS conversion was evaluated at different conditions. The spent Co-containing adsorbents exhibit considerable organic sulfur hydrogenation performance at low temperature, the residual cobalt oxide in sulfided samples will absorb part of hydrogen sulfide and generate new active phase Co₉S₈. By further characterization, it can be found that the unstable Co-S bond on the surface of the sample played a key role in hydrogenation catalysis. Results indicated that the sulfidation degree of the waste adsorbents played a key role in the hydrotreating process. With the temperature increasing from 150~250 ℃, the conversion rate and H₂S selectivity were increased. It is hoped that this paper will provide significant suggestions in waste adsorbents treatment for future work.