(2023) Chemical Engineering Journal_CO₂-mediated thermal treatment of disposable plastic food containers

Jung S., Tsang Y.F., Kwon D., Choi D., Chen W.-H., Kim Y.-H., Moon D.H., Kwon E.E.

(Elsevier B.V.) Chemical Engineering Journal ISSN: 13858947 Vol.451 Issue. Article No.138603 DOI: 10.1016/j.cej.2022.138603

In accordance with global economic prosperity, the frequencies of food delivery and takeout orders have been increasing. The pandemic life, specifically arising from COVID-19, rapidly expanded the food delivery service. Thus, the massive generation of disposable plastic food containers has become significant environmental problems. Establishing a sustainable disposal platform for plastic packaging waste (PPW) of food delivery containers has intrigued particular interest. To comprise this grand challenge, a reliable thermal disposable platform has been suggested in this study. From the pyrolysis process, a heterogeneous plastic mixture of PPW was converted into syngas and value-added hydrocarbons (HCs). PPW collected from five different restaurants consisted of polypropylene (36.9 wt%), polyethylene (10.5 wt%), polyethylene terephthalate (18.1 wt%), polystyrene (13.5 wt%), polyvinyl chloride (4.2 wt%), and other composites (16.8 wt%). Due to these compositional complexities, pyrolysis of PPW led to formations of a variety of benzene derivatives and aliphatic HCs. Adapting multi-stage pyrolysis, the different chemicals were converted into industrial chemicals (benzene, toluene, styrene, etc.). To selectively convert HCs into syngas (H₂ and CO), catalytic pyrolysis was adapted using supported Ni catalyst (5 wt% Ni/SiO₂). Over Ni catalyst, H₂ was produced as a main product due to C[sbnd]H bond scission of HCs. When CO₂ was used as a co-reactant, HCs were further transformed to H₂ and CO through the chemical reactions of CO₂ with gas phase HCs. CO₂-assisted catalytic pyrolysis also retarded catalyst deactivation inhibiting coke deposition on Ni catalyst. © 2022 Elsevier B.V.

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF- 2021R1I1A1A01052241 ). This work was supported by the Environment and Conservation Fund of the Hong Kong Special Administrative Region Government (No. 2020-76), and the Dean’s Research Fund (Ni. DRF/IRS-7/IRS-4) of The Education University of Hong Kong.