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

Abstract

• Novel NO/SO 2 removal technique by a dual ions-dual oxidants system was proposed. • Dual ions-dual oxidants system displays higher free radical yield and removal efficiency. • Oxidation via OH and SO 4 − plays a key role in the pollutant removal. • No by-products are produced in pollutant removal process using this new technique. A novel simultaneous removal technique of NO and SO 2 from simulated flue gas using a double metal ions-double oxidants coactivation system (Cu 2+ /Fe 2+ /Oxone/H 2 O 2 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 Cu 2+ , and is reduced with increasing inlet contents of NO and SO 2 . Changing operating temperature, reagent pH value or concentrations of Fe 2+ and H 2 O 2 have dual influence on the NO removal efficiency. SO 2 is 100% removed within all studied process parameters. The products of NO and SO 2 removals mainly contain recyclable nitric acid and sulphuric acid after the reaction, and no by-products are found. Oxidation by OH and SO 4 - possesses a crucial role for removing NO, which is the primary pathway of the NO removal.