Heterogeneous Fenton catalysts prepared from modified-fly ash for NOx removal with H2O2

Heterogeneous Fenton catalysts were developed from fly ash by alkali, acid and alkali-acid modification for NOx removal using H2O2 .The experimental results showed that the catalyst derived from alkali-add modification achieved 90% NO. removal efficiency at 140 degrees C, 0.07 mg/min of H2O2 mass flow rate (2 mol/L H2O2)and 250 mL/min of simulated flue gas stream containing 500 ppm NO. Catalyst characterization revealed that the hematite used contained surface hydroxyl groups, Fe2+, oxygen vacancies and FeOAl, which were considered beneficial to the generation of hydroxyl radicals. This work illustrates potential practical use of fly ash.