Elemental mercury removal from flue gas by CoFe2O4 catalyzed peroxymonosulfate.

A magnetic cobalt ferrite (CoFe2O4) catalyst was prepared by sol-gel method, and characterized by a X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Brunauer-Emmett-Teller (BET) and hysteresis loop method. The chemical states on surface of the fresh and spent catalysts were analyzed by a X-ray photoelectron spectroscopy (XPS). The experiments of elemental mercury (Hg0) removal from flue gas were conducted in a laboratory scale using activated peroxymonosulfate (PMS) catalyzed by CoFe2O4, and the effects of the dosage of catalyst, the concentration of PMS, initial solution pH and reaction temperature on mercury removal efficiency were investigated. The average removal efficiency of Hg0 could maintain steady at 85% in 45min when the concentrations of CoFe2O4 and PMS were 0.288g/L and 3.5mmol/l respectively, solution pH was 7 and reaction temperature was 55°C. In order to speculate the reaction mechanism, ethyl alcohol and isopropyl alcohol were used as the quenching agents to indirectly prove the existence of SO4- and OH.