Nitrogen oxides absorption into aqueous nitric acid solutions containinghydrogen peroxide tested using a cables-bundle contactor

Özet

This work aims to study the removal of dilute nitrogen oxides from gaseous effluents by absorption into aqueousnitric acid solutions containing or not hydrogen peroxide.NOx absorption tests (pNOx = 50 Pa with a varying composition) were performed in a cables-bundle con-tactor at ambient conditions. Tests runs were carried out with the recycling of the absorbent solution (0–8 mol/lfor HNO3and 0–2 mol/l for H2O2) allowing to observe the temporal evolution of the absorption efficiency. Theeffects of the different operating conditions on the NO, NO2and NOx absorption performances (A) were in-vestigated.Results revealed in all the cases that ANOxincreases when increasing the proportion of more oxidized speciesin NOx. Without H2O2ANOxdecreases when the HNO3concentration of the solution is increased and also withthe recycling of the scrubbing liquid, leading to NOx desorption phenomena. When hydrogen peroxide is addedto the nitric acid solution the NOx absorption performances are much higher and increase with the initial H2O2concentration and the HNO3concentration.