Pyrolysis of all layers of surgical mask waste as a mixture and its life-cycle assessment

Most of the waste generated from surgical masks waste (WMs) consists of three layers made of conventional nonwoven fabric (upper and lower layers) and a molten blown polypropylene filter mixed with other polymeric additives (middle layer). All these layers are held together by a friction bonding, hence making their separation a difficult task. Their recycling as a mixture is the most cost-efficient solution without the need for further treatments. Within this framework, this research aims to study the pyrolysis of all layers of WMs as a mixture using an experimental set-up with capacity of 200 g at different pyrolysis temperatures (475, 500, 525, and 550 degrees C). The distributions of gases formulated during the entire process were observed. Also, the composition of the obtained pyrolysis products was examined. Finally, the environmental impacts of the proposed process and its environmental benefits were studied using life cycle analysis (LCA-Simapro) based on two different scenarios (oil and wax production). The results showed that at 500 degrees C, the highest oil yield was achieved (42.3%) and smaller amounts of gaseous (54.1%) and calcium-rich char (3.6%) products were generated, while other samples produced wax product with lower yield in the range of 21-36%. The gases measurements showed that methane, ethane and propane were the major gases in the gaseous products, while carbon dioxide and carbon monoxide gases were completely absent. Meanwhile, the GC/MS results showed that the obtained gaseous, oil, and wax products were very rich in flammable compounds, especially 2,4-Dimethyl-1-heptene compound with abundance of 33-38% (gaseous) and 12.5-23.8% (tars). Finally, the LCA results showed that the management of WMs as a mixture via pyrolysis significantly reduced the Global warming potential factor up to 0.244 kg CO2 eq/kg (oil) and 0.151 CO2 eq/kg (wax) with improvement by 90-94%, when compared to incineration management. However, the economic analysis showed that the oil production scenario has a significant contribution to the economic sector with an 85% improvement. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the pyrolysis of surgical masks waste (WMs) as a mixture, aiming to recycle the waste materials and reduce environmental impacts. The results showed that pyrolysis at 500 degrees C achieved the highest oil yield with reduced greenhouse gas emissions. The study demonstrated the effectiveness of this method in reducing environmental impacts and improving economic performance.