Efficient removal of mercury from flue gases by regenerable cerium-doped functional activated carbon derived from resin made by in situ ion exchange method

Cerium-doped activated carbon with high dispersions of cerium and sulfur species was successfully synthesized by an in situ ion exchange method. A high space velocity was employed to differentiate the mercury removal performance of cerium-doped activated carbon with (Ce/AC) and without (Ce/C) activation in simulated flue gases, at 80 to 150 degrees C. The Ce/AC showed much higher mercury removal ability than those of Ce/C, commercial coconut AC and NH4CI modified AC. The main mercury species formed over spent Ce/AC were HgO, HgS and HgSO4. The HgO was formed mainly through the oxidation of mercury by lattice oxygen, while the HgS was generated by the reaction between Ce2S3 and mercury. The formation of HgSO4 might be due to the reaction of mercury with SO2 and/or Ce2S3 with the aid of oxygen. The Ce/AC showed impressive regeneration and reuse ability, the mercury removal performance of which showed no obvious change even after 5 runs of regeneration. The mercury species formed over Ce/AC also had no obvious change after regeneration; however, the Ce2S3 over Ce/AC was converted to CeO2 after regeneration. With the above excellent properties, Ce/AC may prove to be an advantageous alternative to commercial AC for mercury removal in power plants.