Performance, mechanism, and kinetics of NO removal by combined ascorbic acid and FeIIEDTA reaction systems

Fe(II)EDTA complexation technology is one of the most promising processes to realize NO removal. but Fe(II)EDTA is easily oxidized to Fe(III)EDTA losing activity, which limits its further application. To solve this problem, ascorbic acid (VC) combined with Fe(II)EDTA was used for NO removal. The influences of various operating parameters like Fe(II)EDTA concentration, VC concentration, original pH value and temperature on NO removal in bubbling device were examined preliminarily. The results revealed that the VC can greatly improve NO removal by Fe(II)EDTA. NO removal efficiency increased with the increasing of VC concentration as well as Fe(II)EDTA concentration. Low temperature or low O-2 concentration was conducive to the absorption of NO. NO removal efficiency increased and then decreased with pH value increasing. For initial Fe(II)EDTA concentration of 0.016 M, pH and temperature had little effect on NO removal efficiency. In addition, the kinetic studies showed that compared with normal Fe(II)EDTA approach, NO absorption by mixed Fe(II)EDTA and VC was more effective in reducing total mass transfer resistance and enlarging the NO flux. The absorption process was controlled by the liquid film. Finally, Ncontaining product was determined as NO2- and NO3-, suggesting that NO was mainly translated into nitrite and nitrate.

Automated summary

The combination of Fe(II)EDTA and ascorbic acid greatly improves NO removal efficiency, with NO removal efficiency increasing with higher concentrations of VC and Fe(II)EDTA. Low temperature and low O2 concentration are conducive to NO absorption. The absorption process is controlled by the liquid film and results in the transformation of NO into nitrite and nitrate.