Fe - Zsm - 5 Zeolite Synthesis, Characterization And Denitration Performance Research

Nitrogen oxides (NOX) are one of the important atmospheric pollutants. The ZSM-5zeolite has high catalytic activity in the SCR reaction, and Fe-ZSM-5has been a great deal of concern because it’s high resistance to sulfur, water.In this paper, we synthesized series Fe-ZSM-5zeolite catalysts of different silicon aluminum ratios and different iron content, using dynamic hydrothermal synthesis method. We examined the efficiency of the reaction of Fe-ZSM-5catalyst when NH3acted as a reducing agent, selective catalytic reduction of NO in a fixed bed. In addition, we analyzed the resistance of sulfur and water of the catalyst. The experiment results showed that, under the experimental conditions:the space velocity (GHSV) was5510h’1, the O25%(ψ), the NO concentration900×10-6,[NH3]/[NO] molar ratio1.2, the activity of Fe-ZSM-5catalyst when Si/(Fe+Al)=20, Fe:Al=1:1(molar ratio) between240-390℃was above98%. When the space velocity (GHSV) was5510h-1, O25%(ψ), SO2600×10-6, the Fe-ZSM-5(20,1:1) had outstanding SCR activity (between240-420℃) and was excellently resistant to SO2and H2O in the SCR reaction.X-ray diffraction spectrum (XRD), temperature programmed desorption (TPD), hydrogen programmed reduction (H2-TPR), scanning electron microscopy (SEM), electron paramagnetic spectroscopy (EPR), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and other characterization methods were used to characterize the morphology, structure and the catalytic performance, to find the connection between the catalyst structure and the activity of the catalysts. XRD showed that the Fe-ZSM-5catalysts emerged MFI structure, the characteristic peak appears and no chunks of iron oxide reunion. It was found in SEM that the Fe-ZSM-5catalyst formed microshperes which was made up of many nanocrystalline reunions. NH3and NO-TPD results showed that the amount of acid decreased slowly with Fe/Al increase and Lewis acid sites slightly shifted towards low temperature, and the catalyst on the chemisorption of NO increased and then decreased with increasing Fe/Al. The catalytic activity of Fe-ZSM-5(35.1:1) was high. matching the amount of NO adsorbed on the catalyst when Si/(Al+Fe)=35. When the Fe:Al=1:1. Si/(Al+Fe)=20.35.50. EPR analysis results showed that most iron ion was into the skeleton of ZSM-5:a small part was isolate Fe3+and in the surface of the catalysts. The catalvtic activity increased with the amount of iron.EPR on line studied NH3. NO and O2adsorption on Fe-ZSM-5catalyst, finding that Fe(?) promoted the oxidation of NO and the NH3-SCR process follow the Eley-Rideal mechanism.