A novel double metal ions-double oxidants coactivation system for NO and SO2 simultaneous removal

A novel simultaneous removal technique of NO and SO2 from simulated flue gas using a double metal ions-double oxidants coactivation system (Cu2+/Fe2+/Oxone/H2O2 coactivation system) was proposed. Process parameters optimization, products, free radicals and mechanisms of pollutant removal were studied. Results demonstrate that the double metal ions-double oxidants coactivation system achieves far higher free radical yield and pollutant removal efficiency relative to other contrasting systems, which are associated with the redox cycling by double metal ions and the free radical capture intermediate formed between double oxidants. NO removal efficiency is increased with higher concentrations of Oxone and Cu2+, and is reduced with increasing inlet contents of NO and SO2. Changing operating temperature, reagent pH value or concentrations of Fe2+ and H2O2 have dual influence on the NO removal efficiency. SO2 is 100% removed within all studied process parameters. The products of NO and SO2 removals mainly contain recyclable nitric acid and sulphuric acid after the reaction, and no by-products are found. Oxidation by (OH)-O-center dot and SO4-center dot possesses a crucial role for removing NO, which is the primary pathway of the NO removal.

Automated summary

In this study, a novel technique for simultaneous removal of NO and SO2 was proposed using a double metal ions-double oxidants coactivation system. The results showed that this system achieved higher free radical yield and pollutant removal efficiency compared to other systems. The removal efficiency of NO increased with higher concentrations of Oxone and Cu2+, but decreased with increasing inlet contents of NO and SO2. SO2 was completely removed under all studied process parameters.