An absorption efficiency of sieve plate column to remove nitrogen oxides with water and diluent nitric acid was studied.
The removal efficiencies of nitrogen oxides and the acidities of produced acids were obtained from experimental measurement.
$NO_x$ absorption processes accompanied with chemical reaction of $NO_x-H_2O-HNO_x$ system produce $HNO_3$ and $HNO_2$ in liquid phase.
The subsequent dissociation of $HNO_2$ in liquid phase resulted in the formation of $HNO_3$ and NO gas.
NO gas is reacted with $NO_2$ to $N_2O_3$ or oxidized to $NO_2$.
A mathematical model was developed based on the absorption mechanism, chemical reaction and mass transfer.
This model is presented and discussed with the experimental results.
The validity of this model was shown by the good agreement with experimental results.