Optimization of wet denitration by dual oxidant (H2O2/S2O82 −) advanced oxidation process

- NO removal efficiency and NO absorption rate were the assessment indicators.
- The assessment indicators were modelled by second order polynomial.
- The interactive effect of temperature and pH had the most significant impact.
- Temperature, pH and Na2S2O8/H2O2 molar ratio were acted as the optimized parameters.
- In H2O2/S2O82 − wet denitration process, the optimized parameters were determined.

A new type of wet denitration oxidant, which was composed of H2O2 and Na2S2O8, had been studied for its removal performance of NO from flue gas in a bubble column reactor. The interactive effects of pH, temperature and molar ratio of Na2S2O8/H2O2 on NO removal efficiency and NO absorption rate were investigated by a three-factor Box-Behnken design. The second order polynomial models were obtained to describe the relationship between the operation conditions and the responses. The results of analysis of variance such as the coefficient of determination, P values, adequate precision values and the lack of fit F-test implied the satisfactory adjustment of the quadratic models. The results of three dimensional plots showed that the interactive effect of temperature and pH had the most significant impact on these responses. The optimized parameters were successfully determined by BBD. Under the obtained optimum conditions of pH (a value of 11), temperature (50 °C) and Na2S2O8/H2O2 molar ratio (a value of 0.005), NO removal efficiency of 78.68% and NO absorption rate of 7.58E-07 mol/m2·s were observed respectively.