Effect of outdoor ageing on pyrolytic characteristics and kinetics of different organic components in waste photovoltaic panels

Pyrolysis is a potential approach for volume reduction and utilization of organic components in waste photovoltaic panels. During a usage period of 20-25 years, the physical and chemical properties of photovoltaic panels might undergo ageing and deterioration, thereby affecting their thermal decomposition characteristics. The characteristics of samples before and after ageing were studied using Fourier transform infrared spectroscopy, scanning electron microscopy, elemental analyzer, and thermogravimetry-Fourier transform infrared spectroscopy-mass spectrometry. There were certain differences in the weight loss temperature, time, residual mass, and activation energy of the samples in the pyrolysis reaction. After ageing, the production of acetic acid and methane in ethylene vinyl acetate pyrolysis products increased, while the production of CO2 decreased. After ageing, Tedlar-Polyethylene Terephalate-Tedlar mainly produced water, carbon dioxide, and fluorocarbon compounds, and the percentage of harmful fluorocarbon compounds in the human body increased. Cyclosiloxane, CO2, and hydrocarbons containing C-H bond were detected in each weight-loss stage of aged silica gel. As the heating rate changed, the amount of pyrolysis products also changed. Controlling the sample's heating rate would help to lessen the quantity of hazardous pollutants that were produced. The influence of ageing on the weight loss of mixed samples was discussed. This study seeks to give a fundamental understanding of the physicochemical properties, pyrolysis behaviour, and volatiles of samples before and after ageing, thus providing helpful insights for the final disposal or recovery of waste photovoltaic panels through pyrolysis.