Pyrolysis behavior, kinetics, and thermodynamics of waste pharmaceutical blisters under CO2 atmosphere

Binhui Wang; Zhitong Yao; Markus Reinmöller; Nanda Kishore; Fiseha Tesfaye; Rafael Luque

doi:10.1016/j.jaap.2023.105883

Pyrolysis behavior, kinetics, and thermodynamics of waste pharmaceutical blisters under CO₂ atmosphere

J Anal Appl Pyrolysis. 2023 Mar:170:105883. doi: 10.1016/j.jaap.2023.105883. Epub 2023 Jan 25.

Authors

Binhui Wang¹, Zhitong Yao¹, Markus Reinmöller², Nanda Kishore³, Fiseha Tesfaye⁴, Rafael Luque^{5

6}

Affiliations

¹ College of Materials Science and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
² Technical University of Denmark, DTU Engineering Technology, 2750 Ballerup, Denmark.
³ Department of Chemical Engineering, Indian Institute of Technology Guwahati, Assam 781039, India.
⁴ Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Henrikinkatu 2, FI-20500 Turku, Finland.
⁵ Department of Organic Chemistry, University of Cordoba, Campus de Rabanales, EdificioMarie Curie (C-3), CtraNnal IV-A, Km 396, E14014 Cordoba, Spain.
⁶ Universidad ECOTEC, Km 13.5 Samborondón, Samborondón EC092302, Ecuador.

Abstract

The disastrous impact of COVID-19 pandemic has caused a significantly increased production and use of pharmaceutical drugs, which is accompanied by the rapid generation of waste pharmaceutical blisters (WPBs). Nonetheless, its treatment has not gained appropriate attentions and a perceptible process development was not achieved. In this study, the WPBs pyrolysis in CO₂ atmosphere was conducted as well as the thermodynamics and kinetics were investigated. The thermogravimetric analysis revealed that the WPBs decomposition could be divided into two stages of 25 - 365 °C and 365 - 900 °C with mass loss of 56.5 - 60.5 wt% and 22.5 - 25.9 wt%, respectively. Fourier-transform infrared spectroscopy analysis indicated the dechlorination process initiating at ∼300 °C. The simultaneous asymmetric stretching of HCl and stretching vibration of C-Cl bond was detected in the range of 2600 - 3250 cm^-1 and 660 - 750 cm^-1, respectively. The dechlorination reactions were almost complete at ∼520 °C and minor peaks (2900 -3100 cm^-1) due to C-H vibrations were observed. Gas chromatography-mass spectrometry analysis indicated that the evolved products included alkanes, benzene, olefin, as well as HCl. The cycloalkenes content significantly increased during the second conversion stage, implying the addition reactions between alkanes and olefins. The apparent activation energy was calculated using three model-free methods and the values from Flynn-Wall-Ozawa model increased from 142.0 to 255.8 kJ·mol^-1 with an average value of 147.4 kJ·mol^-1. The methods of Coats-Redfern as well as Malek were applied to determine the reaction mechanism. The one-dimensional diffusion model was more reliable to describe the WPBs pyrolysis. This study will represent a significant reference case for the thermochemical conversion of multilayer packing waste and facing the increasing demand for the medical waste recycling.

Keywords: COVID-19 pandemic; Medical waste; Multilayer packaging; Pharmaceutical blisters; Thermochemical conversion.