Removal and recovery of gas-phase element mercury by metal oxide-loaded activated carbon

Abstract

The reusability of Co 3O 4 (AC-Co), MnO 2 (AC-Mn) and CuCoO 4 (AC-CC) loaded activated carbon (AC) and their element mercury removal efficiency had been studied using a laboratory-scale fixed-bed reactor under simulated flue gas conditions. Tests showed that spent AC-Co could be regenerated through heating at 673 K under N 2 atmosphere and the enrichment regenerated Hg 0 could be collected to eliminate the secondary pollution. Regenerated AC-Mn and AC-CC's Hg 0 removal efficiency decreased greatly due to AC's decomposition and MnO 2's crystal structure variation. Compared with AC and metal oxides, metal oxide-loaded AC had higher Hg 0 capture ability and capacity due to AC huge surface areas and lots of function groups. TGA analysis results showed that AC-Co and AC-Mn's HgO adsorptive capacity at 523 K reached 19.8 mg g −1 and 5.21 mg g −1, respectively. High loading values and adsorption temperatures were beneficial to AC-Co's Hg 0 removal efficiency. However, CuCoO 4 and MnO 2's AC decomposition ability had negative effect on AC-CC and AC-Mn's performance, respectively, especially at high adsorption temperatures and loading values. SO 2 tests showed that AC-CC had higher anti SO 2-poisoning ability than AC-Co and AC-Mn.