Catalytic Pyrolysis Kinetic Behavior and TG-FTIR-GC-MS Analysis of Metallized Food Packaging Plastics with Different Concentrations of ZSM-5 Zeolite Catalyst.

Justas Eimontas,Nerijus Striūgas,Samy Yousef,Mohammed Ali Abdelnaby

doi:10.3390/polym13050702

Abstract

Recently, the pyrolysis process has been adapted as a sustainable strategy to convert metallized food packaging plastics waste (MFPW) into energy products (paraffin wax, biogas, and carbon black particles) and to recover aluminum. Usually, catalysts are used in pyrolysis treatment to refine pyrolysis products and to increase their yield. In order to study the effect of a catalyst on the formulated volatile products, this work aims to study the pyrolysis behavior of MFPW in presence of catalyst, using TG-FTIR-GC–MS system. The pyrolysis experiments were conducted with ZSM-5 Zeolite catalyst with different concentrations (10, 30, and 50 wt.%) at different heating rates (5, 10, 15, 20, 25, and 30 °C/min). In addition, TG-FTIR system and GC-MS unit were used to observe and analyze the thermal and chemical degradation of the obtained volatile compounds at maximum decomposition peaks. In addition, the kinetic results of catalytic pyrolysis of ZSM-5/MFPW samples matched when model-free methods, a distributed activation energy model (DAEM), and an independent parallel reaction kinetic model (IPR) were used. The TGA-DTG results showed that addition of a catalyst did not have a significant effect on the features of the TGA-DTG curves with similar weight loss of 87–90 wt.% (without taking the weight of the catalyst into account). Meanwhile, FTIR results manifested strong presence of methane and high-intensity functional group of carboxylic acid residues, especially at high concentration of ZSM-5 and high heating rates. Likewise, GC-MS measurements showed that Benzene, Toluene, Hexane, p-Xylene, etc. compounds (main flammable liquid compounds in petroleum oil) generated catalysts exceeding 50%. Finally, pyrolysis kinetics showed that the whole activation energies of catalytic pyrolysis process of MFPW were estimated at 289 kJ/mol and 110, 350, and 174 kJ/mol for ZSM-5/MFPW samples (10, 30, and 50 wt.%, respectively), whereas DAEM and IPR approaches succeeded to simulate TGA and DTG profiles with deviations below <1.

Highlights

Pyrolysis kinetics showed that the whole activation energies of catalytic pyrolysis process of metallized food packaging plastics waste (MFPW) were estimated at 289 kJ/mol and 110, 350, and 174 kJ/mol for ZSM-5/MFPW samples (10, 30, and 50 wt.%, respectively), whereas distributed activation energy model (DAEM) and independent parallel reaction kinetic model (IPR) approaches succeeded to simulate TGA and DTG profiles with deviations below
The pyrolysis kinetic of MFPW was studied using model-free and independent parallel reaction (IPR) [19,29], while the catalytic pyrolysis kinetic of MFPW and the effect of the concentration of catalyst on their compounds are still missing. Within this frame and in order to better understand the catalytic pyrolysis kinetic behavior of MFPW, this work aims to study the catalytic pyrolysis of MFPW in presence of ZSM-5 Zeolite catalyst with different loads (10, 30, and 50 wt.%), using TG-FTIR-GC–MS system
It appears due to char devolatilization/decomposition and aluminum fraction residue [19,28]. It is clear from the experimental TGA data that increasing amount of the catalyst leads to a significant increase in the thermal resistance of the decomposed samples in terms of total weight loss, which was estimated at 87% (0 wt.%), 82% (10 wt.%), 68% (30 wt.%), and 59% (50 wt.%); this is due to the fact that the pyrolysis process is not able to decompose ZSM-5 Zeolite catalyst and leaves it as a residue, and it must be removed from the calculated TGA

Summary

Introduction

Pure plastic waste is polymeric waste composed from polymer component (e.g., mechanical components, spine, etc.) or it has only layers made from bags, packages, etc., [15] This kind of waste can decompose during the pyrolysis treatment into oil and small amount of char. The second category (metallized plastic waste) is defined as single or multi polymeric layers coated or joined with metal layer (metallized food packaging plastics waste (MFPW)) with high environmental impact [16,17] This category, including (MFPW), is rich in volatile matter (up to 99.5 wt.%), it is classified as the most complex part of plastic waste with poor recycling rate

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