Enhancement of NO absorption in ammonium-based solution using heterogeneous Fenton reaction at low H2O2 consumption

Abstract

A novel NO removal system is designed, where NO is initially oxidized by •OH radicals from the decomposition of hydrogen peroxide (H2O2) over hematite and then absorbed by ammonium-based solution. According to the high performance liquid chromatography (HPLC) profile and the isopropanol injection experiments, the •OH radicals are proved to play a critical role in NO removal. The NO removal efficiency primarily depends on H2O2 concentration, gas hourly space velocity (GHSV), H2O2 feeding rate and reaction temperature, while the flue gas temperature slightly affects the NO removal efficiency. The low H2O2 consumption makes this system a promising technique in NO removal process using wet-method. The evolution of catalyst in reaction is analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), Fourier Transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The nitrite ion and nitrate ion in aqueous solution are detected by the continuous phase flow analyzer. Finally, the macrokinetic parameters of the NO oxidation are obtained by using the initial rate method.