LAUSR

Abstract The Cu/ZSM-5 was used to study the effects of SO3 on mercury removal. The addition of SO2 decreased the Hg0 removal efficiency but the efficiency increased from 82% to 95% after 21 ppm SO3 was introduced at 200 °C. The inhibition effect of SO2 on mercury removal was weakened at 400 °C and the promotion effect of SO3 on mercury removal was enhanced significantly. HgSO4 was the main mercury species formed on the catalyst in the presence of SO3. The in-situ FTIR results showed a large number of S-related peaks were generated on the surface of the catalyst with SOx (SO2 and SO3). The peak of adsorbed SO2 weakened when SO2 and SO3 coexisted in the reaction atmosphere. This is due to the SO3 inhibiting the adsorption of SO2. The peak of adsorbed SO3 was the most obvious and was then gradually consumed after Hg0 introduced. Meanwhile, the peak of sulphate appeared on the surface of the catalyst. This indicated SO3 preferentially adsorbed on the catalyst to form active sites for oxidizing Hg0 to HgSO4. The adsorption of SO3 on the catalyst was promoted at 400 °C, compared with 200 °C, which directly contributed to the enhancement of Hg0 removal.