Removal of Elemental Mercury from Flue Gas Using Cobalt-Containing Biomaterial Carbon Prepared from Contaminated Iris sibirica Biomass

摘要

Iris sibirica biomass (ISBM) used for cobalt (Co) pollution remediation was prepared by one-step pyrolysis and employed to remove elemental mercury (Hg~(0)) from flue gas. Results showed that the ISBM pyrolyzed at 700 °C (ISBM700) exhibited good Hg~(0) removal performance (about 86%) at 150 °C. The existence of NO and O_(2) facilitated the removal of Hg~(0), while SO_(2) and water vapor inhibited it. Characterization analysis (including N_(2) adsorption–desorption, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectrometry) showed that ISBM700 has a relatively higher specific surface area, a quantity of lattice oxygen derived from well-dispersed amorphous-phase CoO_(x ), and abundant oxygen functional groups. A Mars–Maessen mechanism is thought to be involved in the Hg~(0) removal process. The adsorbed Hg~(0) could be oxidized to HgO by the surface oxygen species derived from CoO_(x ), and then, the consumed surface oxygen species can be replenished by O_(2). Therefore, the Co-contaminated I. sibirica biomass (CCIB) from phytoremediation could be utilized for Hg~(0) removal after being pyrolyzed instead of any chemical modification.