Simultaneous removal of SO 2 and NO by wet scrubbing using aqueous chlorine dioxide solution

Abstract

The present study attempts to generate chlorine dioxide (ClO 2) gas continuously by chlorate–chloride process and to utilize it further to clean up SO 2 and NO x gases simultaneously from the flue gas in the lab-scale bubbling reactor. Experiments were carried out to examine the effect of various operating parameters like input SO 2 concentration, input NO concentration, pH of the reaction medium, and ClO 2 feeding rate on the SO 2 and NO x removal efficiencies at 45 °C. Complete oxidation of NO into NO 2 occurred on passing sufficient ClO 2 gas into the scrubbing solution. SO 2 removal efficiency of about 100% and NO x removal efficiency of 66–72% were achieved under optimized conditions. NO x removal efficiency decreased slightly with increasing pH and NO concentration. Input SO 2 concentration had marginal catalytic effect on NO 2 absorption. No improvement in the NO x removal efficiency was observed on passing excess of chlorine dioxide in the scrubbing solution.