Pyrolysis kinetics and thermodynamic parameters of plastic grocery bag based on thermogravimetric data using iso-conversional methods

Abstract

The enormous growth in the consumption of plastic grocery bags and their non-biodegradability nature has become a serious cause of waste generation. In the context of the disposal of plastic, pyrolysis is a promising technique that addresses the energy crisis issue too. Therefore, in this work, pyrolysis kinetics and thermodynamic parameters of plastic grocery bags were investigated using different iso-conversional methods (Starink, Kissinger–Akahira–Sunose, Ozawa–Wall–Flynn, and Friedman methods) based on thermogravimetric analysis data at multiple heating rates (10, 20, 30, and 40 K/min). The pyrolysis of plastic grocery bags followed a single-step degradation process. The average activation energy values were found to be 133.21, 133.80, 139.12, and 192.08 kJ/mol from Starink, Kissinger–Akahira–Sunose, Ozawa–Wall–Flynn, and Friedman methods, respectively. The average values of the pre-exponential factor (using Kissinger’s equation) varied in between 7.14 × 108 and 1.47 × 1013 min−1. From the generalized master plot, it has been observed that the one-dimensional diffusion model is the most suitable one to describe the pyrolysis process. The trends of the thermodynamic parameters reveal the ease of reaction of the plastic grocery bag, as well as it is approaching the thermodynamic equilibrium state during the pyrolysis process. This investigation on the pyrolysis kinetics and thermodynamic parameters would be a reference in designing and scaling the reactor for the treatment of plastic grocery bags.