Regeneration Mechanism of Deactivated Zeolite-Supported Catalyst for the Combustion of Chlorinated Volatile Organic Compounds
Industrial catalysis is confronted with a common problem of catalyst deactivation. In the environmental remediation field of chlorinated volatile organic compounds (Cl-VOC) elimination, one of industrially important challenges is to find an effective solution for the regeneration and re-use of deactivated catalysts within industrial settings. The aim of this work is to evaluate the feasibility of regenerating a deactivated catalyst in the combustion of Cl-VOCs. Chlorobenzene (CB) was used as a reference in this work. The efficiency of the regeneration method for the deactivated catalyst was analyzed by testing the conversion and stability using a metal-exchanged H-zeolite (Cu-Nb/HZSM-5) catalyst. By confirming the related reaction mechanism via in situ diffuse reflectance infrared Fourier transform spectroscopy, the catalysts were analyzed in terms of their carbon deposition, surface elemental content, and acidity, before and after the regeneration. It was found that humid air was more effective than normal air in recovering the properties of the catalyst at 400 °C; at this temperature, the adsorbed coke and chlorine on the surface of the deactivated catalyst were completed removed, and the catalytic performance was recovered to 100% that of the fresh catalyst.