Method of treating exhaust gases containing nitrogen oxides and sulfurous acid gas

摘要

A method of removing NOx and SO2 from an exhaust gas containing NOx and SO2 which comprises contacting an exhaust gas containing NOx and SO2 with an aqueous solution containing M2SO3, an iron ion and an aminopolycarboxylic acid to absorb NOx and SO2 in the aqueous solution and treating the resulting absorbing solution while preventing a contact of the solution with the exhaust gas, thereby to form M2S2O6 in the absorbing solution and reducing NOx to N2. The M2S2O6 formed in the absorbing solution can be easily removed by crystallization separation. With such method, NOx and SO2 can be removed from exhaust gases at high rates and the absorbing solution can be easily regenerated and recycled to the absorbing zone.