Low Temperature Desulfurization of H2S: High Sorption Capacities by Mesoporous Cobalt Oxide via Increased H2S Diffusion

Abstract

Mesoporous cobalt oxides (M-Co-X, X = 150, 250, 350, 450 °C) with tunable porosity and crystallinity were synthesized based on an inverse micelle soft template method. They are the members of recently discovered University of Connecticut (UCT) mesoporous materials. The M-Co-X materials were investigated as desulfurizing sorbents in a fixed bed reactor in the temperature range of 25–250 °C. A considerably high sulfur sorption capacity was observed even at room temperature (13.4 g S/100 g sorbent), and very high values were observed in the temperature range of 175–250 °C (65.0–68.9 g S/100 g sorbent). The sulfided materials were further analyzed with LA-XRD, WA-XRD, N2 sorption studies, FESEM, FESEM-EDX, TEM, FETEM-EDX, TGA, and TPO. The M-Co-250 material reached 100% theoretical sulfur capacity at 150 °C. The presence of interconnected intraparticle voids and surface exposed particles were found to be the critical factors determining the ability of H2S to diffuse in the sorbent. The mesostruture of the M-Co-X material was preserved even after sulfidation. Other mesoporous metal oxides synthesized by the same method (Cr2O3 (UCT-37), CuO (UCT-11), Mn2O3 (UCT-1), and Fe2O3 (UCT-5)) also showed sulfur capacities of 2–200 times more than the corresponding nonporous materials.