In the present work, the effects of relevant system parameters on the oxidation removal of NO using the Fenton method were discussed in detail. Moreover, the impacts of ions remaining in the coal-fired process on the NO oxidation efficiency were investigated specifically. The experimental results showed that the oxidation efficiency of NO decreased with the increase of gas flow rate, reagent temperature, and CO2 volume fraction in the evaluated range, while it increased first and then decreased with the increase of gas temperature, NO initial concentration, O2 volume fraction, initial pH of reagent, and Fe2+/H2O2 molar ratio. In addition, the corresponding impact mechanism of the system parameters was discussed respectively. Although the SO2 showed a competitive effect on the utilization of oxidative radicals, the Fenton system also showed an ability for simultaneous removal of NO and SO2. Furthermore, the results indicated that the NO oxidation efficiency would be influenced by the residual ions, such as Ca2+, Mg2+, Na+, SO42-, and Cl-. The presence of the mentioned ions showed an inhibiting effect on the oxidation removal of NO in the first few minutes, while the NO oxidation efficiency would be enhanced in the bulk stage of the tests. The positive effect trended to be more obvious with the decline of the ion dosage. Subsequently, the influence mechanism of the aforesaid residual cations and anions was supposed and proposed preliminarily.
Keywords: Anion; Cation; Fenton; Flue gas; NO; Oxidation.