Ftir In-Situ Investigation of Zeolite Activation

Abstract Activation of powdered, undiluted zeolites was studied in-situ by FTIR diffuse reflectance (DRIFT) spectroscopy. From the DRIFT spectra we constructed contour plots, which display the process quasi continuously. At temperatures below 200°C, the diffusion of water and ammonia towards the cation coordination sphere is seen. The maximum loss of a particular NH species was observed at 500°C. The concentration of OH species increases most strongly at 430°C, after the on-set of an almost uniform decomposition of all NH species. The activation of 0.93 NH 4 + erionite was completed at around 600°C.