Fabrication and Fractality of Fe2O3-CeO2/ZSM-5 Composites for High-Temperature Desulfurization

Fe2O3/ZSM-5 modified with Ce via citrate route (sol-gel approach) is applied for H2S removal in 500–700 ◦C temperature range. The sulfidation activity of Fe2O3/ZSM-5 is appreciably promoted by introduction of Ce plausibly attributed to the synergy of Fe2O3 and CeO2. 5Fe5Ce/ZSM-5 performs the optimal desulfurization behavior at 600 ◦C with sulfur capacity of 1020 μmol S/g, and the sulfidation process conforms to non-catalytic gas-solid redox reaction mechanism, which yields FeS2, Ce2S3, and S. Fractal analysis is introduced to evaluate the surface porous structure and the adsorption capacity of the sorbent. Its surface fractal dimension is estimated by using Frenkel-Halsey-Hill (FHH) model. It considerably increases after sulfidation plausibly attributed to the formation of a few heterogeneous sulfides or elemental sulfur, which block or cover the surface pore structures of sorbents.