Simultaneous oxidation absorption of NO and Hg0 using biomass carbon-activated Oxone system under synergism of high temperature

Abstract

Compared with the heterogeneous activation technology activated by transition metal oxides, the biomass carbon-activated Oxone technology receives extensive attention because it does not produce metal ion leakage (no secondary pollution). Here a biomass carbon-activated Oxone system under synergism of high temperature was designed to achieve simultaneous oxidation absorption of NO and Hg0 from simulated flue gas. The feasibility, mechanism, products and main technical influencing factors of NO and Hg0 simultaneous removal using this system were explored. The developed removal technique gains a high simultaneous removal efficiency of NO and Hg0 (respectively reaching 91.5% and 98.8%). Based on removal efficiency comparison, free radicals determination and sacrificial agent experiment, hydroxyl radical is proved to be a dominant oxidant for NO removal, and sulfate radical is the second important oxidant for NO removal. Sulfate radical is found to be a dominant oxidant for Hg0 removal, and hydroxyl radical is the second important oxidant for Hg0 removal. Synergistic effect of high temperature and biomass carbon plays a vital role in efficient removal of NO and Hg0. Increasing Oxone concentration, temperature and biomass carbon concentration enhance simultaneous oxidation absorption process of NO and Hg0. However, increasing pH and concentrations of NO and Hg0 reduces simultaneous removal efficiency of NO and Hg0. The main products of NO and Hg0 simultaneous oxidation absorption are NO3– and Hg2+, which can be recycled through the proposed product post-treatment route.