Removal of elemental mercury by Ce and Co modified MCM‐41 catalyst from simulated flue gas

Abstract

AbstractCo and Ce based catalysts have been proven to possess a high Hg0 removal efficiency. However, these catalysts have a low dispersion of active components and low mass transfer rate, which limits their catalytic activity. MCM‐41 has a large surface area and a highly ordered mesoporous structure, which can improve the dispersion of Co and Ce, resulting in a high mass transfer rate. In this paper, different amounts of Co and Ce were loaded on MCM‐41 to synthesize Cox‐Cex/MCM‐41. The characteristic results of the catalyst showed that catalysts with a lower Co and Ce loading amount had a high dispersion and a low crystallinity, leading to more activity sites on the catalyst surface. Hence, the Hg0 removal efficiency of the catalysts first increased with the increase of the Co and Ce loading amount. However, with the further increase of the Co and Ce loading amount, the crystallinity of the catalysts increased, which might cause the blockage of the pores and the decrease of BET surface areas, leading to a low Hg0 removal efficiency. Along with the factors mentioned above, Co0.15‐Ce0.15/MCM‐41 had the best catalytic activity, which showed above 85 % Hg0 removal efficiency in the temperature range of 200–300 °C at 180 000 h−1. Flue gas components had different effects on catalytic activity. O2 and NO could promote, but H2O and SO2 inhibit the Hg0 removal efficiency. The simulated flue gas of 300 ppm SO2, 400 ppm NO, 6 % H2O, and 5 % O2 have serious effects on catalytic activity leading to a lower Hg0 removal efficiency of 20 % for Co0.15‐Ce0.15/MCM‐4.