Simultaneous removal of SO2, NO and Hg0 using porous carbon/heat-coactivated persulfate system

Abstract

A novel simultaneous removal technique of SO2, NO, and Hg0 using porous carbon/heat-coactivated persulfate (PS) system was proposed. A series of experiments and theoretical analysis were conducted to explore simultaneous removal process of Hg0, SO2, and NO. Study demonstrates that the developed porous carbon/heat-coactivated PS system gains larger free radical yield and higher pollutants simultaneous removal efficiency than other comparison systems, which are associated with the synergism between porous carbon and heat. High temperature plays a vital role in this co-activation system. Both SO4−· and ·OH play an important role in NO and Hg0 removal, but ·OH is more important for NO removal while SO4−· is more important for Hg0 removal. Both NO and Hg0 removal processes meet pseudo-first-order rapid reaction kinetics, and their removal processes are controlled by mass transfer. Removal efficiencies of NO and Hg0 are increased first and then are decreased with increasing PS concentration, temperature and porous carbon concentration. Increasing pH and concentrations of SO2, NO and Hg0 reduce the NO and Hg0 removal efficiencies. The highest simultaneous removal efficiency of Hg0, SO2, and NO is up to 98.4% for Hg0, 100% for SO2, and 89.3% for NO under an optimized test condition.