A systematic review on the efficiency of cerium-impregnated activated carbons for the removal of gas-phase, elemental mercury from flue gas

In the present systematic review, we aimed to collect and analyze all the relevant evidence on the efficiency of cerium-impregnated versus virgin-activated carbons (ACs) for the removal of gas-phase elemental mercury (Hg-0) from the flue gas of coal-fired power plants and to assess the effect of different calcination and operational parameters on their efficiency. A total of eight relevant papers (out of 1193 hits produced by the search) met the eligibility criteria and were included in the study. Results indicated that the Hg-0 adsorption capacity of cerium-impregnated ACs is significantly higher than that of virgin ACs, depending highly on the impregnation and operational parameters. It was noticed that although cerium-impregnated ACs possessed smaller surface areas and pore volumes, their Hg-0 removal efficiencies were still higher than their virgin counterparts. An increased Hg-0 removal efficiency was in general found by increasing the operational adsorption temperature as high as 150-170 degrees C. Studies also indicated that NO, SO2, and HCl have promoting impacts on the Hg-0 removal efficiency of Ce-impregnated ACs, while H2O has an inhibitory effect.