Selective catalytic reduction of NO using acetone solvent vapors as the reducing agent over Cu2+ and/or Al3+ ions substituted MCM-41 catalysts

Abstract

Selective catalytic reduction (SCR) of nitrogen monoxide (NO) using acetone solvent vapors as the reducing agent over mesoporous Cu-MCM-41, Al-MCM-41, Cu-Al-MCM-41 and CuO supported metal oxides such as CuO/Al2O3 and CuO/SiO2 was investigated in this study. The synthesized materials were characterized by using powder low-angle X-ray diffraction (XRD), N-2 adsorption-desorption measurements, Al-27 magic angle spinning-nuclear magnetic resonance spectroscopy (MAS-NMR), electron paramagnetic resonance spectroscopy (EPR) and inductively coupled plasma-mass spectrometer (ICP-MS) analysis. The presence of isolated Cu2+ ions and tetrahedrally coordinated Al3+ ions within the framework of Cu-Al-MCM-41 catalyst played a vital role in this deNOx reaction as confirmed by EPR and (27)AlMAS-NMR spectroscopic studies, respectively. Among the various catalysts studied, bifunctional Cu-Al-MCM-41 was found to be the most effective catalyst for achieving maximum deNOx activity at lower temperatures of around 250-350 degrees C. Besides, Cu-Al-MCM-41 catalyst also showed higher acetone oxidation than those of Cu-MCM-41, CuO/Al2O3 and CuO/SiO2 catalysts in the entire temperature range. For higher temperature of above 400 degrees C, it was found that Cu-MCM-41 catalyst shows highest activity for the NO reduction but it shows less acetone incineration activity as compared to that of Cu-Al-MCM-41 catalyst. The study of simultaneous removal of NO and acetone solvent vapors using Cu-Al-MCM-41 and Cu-MCM-41 catalysts reveals the potential of using waste organic solvents from industry as the reducing agent of deNOx (SCR) process. (C) 2013 Elsevier B.V. All rights reserved.