Synthesis, Stability, and Sulfation Properties of Sol-Gel-Derived Regenerative Sorbents for Flue Gas Desulfurization

The sol-gel method is applied to prepare γ-alumina-supported copper oxide and calcium oxide sorbents containing 10-50 wt % active species. The prepared sorbents are characterized for their pore texture, dispersion of active species on the surface of support, and desulfurization properties. The sol-gel-derived alumina-supported sorbents have a relatively large surface area (>200 m²/g) and pore volume (>0.3 cm³/g) and uniform pore size distribution (20-60 Å). Thermal and chemical stability of the sol-gel-derived sorbents is studied by comparing the pore texture data of the sorbents before and after several different heat treatments. The stability results show that the pore structure of the sol-gel-derived sorbents is stable in the normal conditions of the flue gas desulfurization process. It is found that CuO/γ-Al₂O₃ sorbent containing 20 wt % of CuO coated as a monolayer or submonolayer on the surface of support has the highest SO₂ sorption capacity (22.5 wt % at 500 °C). The sol-gel-derived CuO/γ-Al₂O₃ sorbent exhibits desired sulfation and regeneration properties.