Determination of the rate of absorption of nitrogen monoxide in hydrogen peroxide by bubbling for sampling of nitrogen oxides in emissions from fixed sources

Different tests of absorption efficiency of nitrogen monoxide gas by bubbling in a hydrogen peroxide solution were carried out maintaining the sampling conditions required by methods 5 and 8 of the U.S. Environmental Protection Agency (U.S. EPA) for gas emissions from stationary sources. Equipment recommended by the U.S. EPA methods were used, as well as tests based on a 2⁴ factorial statistical design with four variables were performed in the experimental stage. Gas flow, type of bubbler, amount of absorbent solution and concentration of hydrogen peroxide were chosen as variables. Absorption efficiencies from 1% to a maximum of 51% were obtained for the different combinations of variables proposed, without reaching the value of 99% required for a representative sampling of nitrogen oxides, according to the U.S. EPA. Higher yield was obtained when the large orifice spargers, the lower gas flow and the higher concentration of hydrogen peroxide were used. The variable amount of absorbent solution had no significant effect on the response variable. The need for a set of 7 bubblers connected in series and the use of the most favorable experimental condition to exceed the 99% absorption efficiency required to be used as a method for representative sampling of nitrogen oxides in air was extrapolated from the results obtained