Gaseous Elemental Mercury Removal Using Combined Metal Ions and Heat Activated Peroxymonosulfate/H2O2 Solutions

Several novel oxidation removal processes of elemental mercury (Hg-0) from flue gas using combined Fe2+/Mn2+ and heat activated peroxymonosulfate (PMS)/H2O2 solutions in a bubbling reactor were proposed. The operating parameters (e.g., PMS/H2O2 concentration, Fe2+/Mn2+ concentration, solution pH, activation temperature, and Hg-0/NO/SO2/O-2/CO2 concentration), mechanism and mass transfer-reaction kinetics of Hg-0 removal were investigated. The results show that heat and Fe2+/Mn2+ have significant synergistic effect for activating PMS and PMS/H2O2 to produce free radicals to oxidize Hg-0. Hg-0 removal is strongly affected by PMS/H2O2 concentration, Fe2+/Mn2+ concentration, activation temperature, and solution pH. SO4-center dot and center dot OH produced from combined heat and Fe2+/Mn2+ activated PMS/H2O2 play a leading role in Hg-0 removal. Under optimized experimental conditions, Hg-0 removal efficiencies reach 100, 94.9, 66.9, and 58.9% in heat/Fe2+/PMS/H2O2, heat/Mn2+/PMS/H2O2, heat/Fe2+/PMS, and heat/Mn2+/PMS systems, respectively. Hg-0 removal processes in four systems belong to fast reaction and were controlled by mass transfer under optimized experimental conditions. (c) 2018 American Institute of Chemical Engineers AIChE J, 65: 161-174, 2019