Absorption of NO in an Aqueous Solution of NaClO2

Abstract

A packed column has been used to study the absorption of nitrogen oxide in an alkaline solution of sodium chlorite. The reactions taking place during the absorption have been examined and a lumped reaction model has been used to estimate rate constants from experimental data. Several parallel and consecutive reactions were found to take place during the absorption. NO was found to be oxidized to NO2and/or to NO2–, and ClO2– was reduced to Cl– and/or to ClO–. The pH value of the absorbing liquid was found to have a great impact both on the absorption rate and on the extent of the different redox reactions within the liquid. Experimental results indicate that sodium chlorite mainly works as an agent to oxidize NO to NO2 and that the major part of the nitrogen oxides are absorbed via the hydrolysis of N2O3 and N2O4.