Effects of MgO-ZSM-23 Zeolite Catalyst on the Pyrolysis of PET Bottle Waste

The pyrolysis reaction of poly(ethylene terephthalate) or PET bottle waste was conducted comparatively in two cases: without catalyst and with MgO-ZSM-23 zeolite catalyst. The pyrolysis of PET was successfully decomposed to the product of liquid/wax, char, and gas (major product). Applying MgO-ZSM-23 catalyst, the product shows pronounced higher yield of gas (72.5 vs. 58.7 wt.%) and less yield of char solid (8 vs. 17.6 wt.%). The gas product shows less yield of CO2 (75 vs. 98 wt.%) but gives higher hydrocarbon gas fractions of C1–C5 (25 vs. 2.1 wt.%). In liquid/wax products, the catalytic pyrolysis shifted the product spectrum from higher molecular weight, e.g., biphenyl, terphenyl to benzene derivatives, predominantly in “benzoic acid”.