Preparation and application of metal loaded ZSM-5 and y-zeolite catalysts for thermo-catalytic pyrolysis of real end of life vehicle plastics waste

Abstract

In this work synthetic zeolite catalysts were modified by metal loading and used for real end of life vehicle plastic waste pyrolysis. ZSM-5 and y-zeolite catalysts were loaded by Ce2+, Cu2+, Fe2+, Fe3+, H+, Mg2+, Ni2+, Sn2+ and Zn2+ and the catalytic effects of both parent and metal loaded catalysts were tested by thermogravimetric method. The catalysts morphology and other properties were followed by N2 adsorption/desorption isotherms, Fourier transformed infrared spectroscopy, Scanning Electron Microscopy and energy dispersive x-ray fluorescent spectroscopy. Significant difference in micropore, mesopore and macropore surface area, and average pore diameter was concluded. In general, the surface areas could be decreased by metal loading onto the catalyst surface. Parent y-zeolite had larger surface areas than that of parent ZSM-5 catalyst. Based on EDXRFS analysis, catalysts were loaded by 8–10% metals. Regarding grain size, in general y-zeolite based catalysts had smaller grains and the distribution was also narrower, than ZSM-5 based catalysts. The Si/Al ratio was 17.11–21.75 in case of ZSM-5 catalysts and 2.04–2.91 regarding y-zeolite catalyst. Based on first order kinetic approach, the reaction kinetic parameters were also calculated and evaluated. Waste end-of life vehicle (ELV) started to decompose at 426 °C (T5%) and finished at 525 °C (T95%). Catalysts can decrease the activation energies of decomposition. Same order of the activation energy decreasing of both ZSM-5 and y-zeolite based catalysts was found: Cu<Ce<Mg<Ni<Fe(III)<Fe(II)<Zn<Sn, however, y-zeolite based catalysts had advanced properties in activation energy decreasing than ZSM-5 based.