NOx scrubbing with H2O2/HNO3 solutions achieved with a laboratory bubble contactor

In this work, the removal of dilute nitrogen oxides NOx from the gaseous effluents of Tunisian nitric acid plant by absorption into aqueous hydrogen peroxide solutions containing or not nitric acid was studied. All semi-continuous absorption tests were carried out at ambient conditions and at 40 Pa as NOx partial pressure. The effects of the gas flow rate, the initial H2O2 concentration and the presence of HNO3 on the NOx absorption efficiency (ANOx) were studied. The tests results revealed that ANOx increases with an increase in initial H2O2 concentration in the scrubbing liquid, but decreases with an increase of gas flow rate. Furthermore, the presence of nitric acid in the aqueous hydrogen peroxide solution has a positive effect on ANOx. These results confirmed that the removal of NOx liberated from the plants of the Tunisian Chemical Group (TCG) by absorption into H2O2 solution is a feasible and an effective solution.