Peroxymonosulfate catalyzed by rGO assisted CoFeO catalyst for removing Hg from flue gas in heterogeneous system.

The cobalt ferrite-reduced oxidized graphene (CoFeO/rGO) catalyst was synthesized by hydrothermal method and characterized by Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscope (SEM), Brunauere Emmette Teller (BET) and Hysteresis loop. For developing a new method of removing elemental mercury (Hg) from flue gas, the effects of catalyst dosage, PMS concentration, solution pH and reaction temperature on the removal efficiency were investigated experimentally by using peroxymonosulfate (PMS) catalyzed by CoFeO/rGO at a self-made bubbling reactor. The average removal efficiency of Hg in a 30-min period reached 95.56%, when CoFeO/rGO dosage was 0.288 g/L, PMS concentration was 3.5 mmol/L, solution pH was 5.5 and reaction temperature was 55 °C. Meanwhile, based on the free radical quenching experiments, in which, ethyl alcohol and tert butyl alcohol were used as quenchers to prove indirectly the presence of OH and SO, the characterizations of catalysts and reaction products, and the existing results from other scholars. The reaction mechanism was proposed.