Removal of NO by using sodium persulfate/limestone slurry: Modeling by response surface methodology.

• NO is removed by using persulfate/limestone slurry. • NO removal process is optimized by RSM. • The maximum value of NO removal efficiency was 85.7%. • Reaction temperature is the most significant factor for NO removal. In this work, NO removal process by using sodium persulfate/limestone slurry was investigated. Based on the response surface methodology, the effects of operation parameters, including reaction temperature, sodium persulfate concentration, initial concentration of NO and the concentration of transition metal ions, on NO removal efficiency were investigated. It was found that reaction temperature was the determining factor in NO removal process among all the variables studied, another significant parameter was the persulfate concentration in the mixed slurry. Moreover, the interaction of the reaction temperature with the persulfate concentration also played an important role for their double activation on the removal process. The proposed model equation using response surface methodology had shown good agreement with the experimental data, with a correlation coefficient (R2) of 0.9511. Through the analysis, it was found that the maximum value of NO removal efficiency (85.7%) could be obtained at the specific reaction temperature (58.3 °C) and sodium persulfate concentration (0.066 mol/L), respectively. Therefore, persulfate/limestone slurry is suitable for efficient NO removal. [ABSTRACT FROM AUTHOR]