(2019) Science of the Total Environment_Coupling carbon dioxide and magnetite for the enhanced thermolysis of polyvinyl chloride

Song H., Tsang D.C.W., Kwon G., Kwon E.E., Cho D.-W.

(Elsevier B.V.) Science of the Total Environment ISSN: 489697 Vol.696 Issue. Article No.133951 DOI: 10.1016/j.scitotenv.2019.133951

To valorize plastic wastes, pyrolysis of polyvinyl chloride (PVC) was conducted as a case study. In an effort to build the more sustainable pyrolysis platform for PVC, CO₂ was particularly employed as a reactive gas medium, and magnetite (Fe₃O₄) was used to explore the feasibility of enhancing CO₂-assisted PVC pyrolysis. The favorable effect of Fe₃O₄ on syngas generation from pyrolysis of PVC was apparent to yield highest concentration of H₂ (0.28 mol% at 590 °C) and CO (4.34 mol% at 800 °C) in the presence of 0.1 g Fe₃O₄/1 g PVC. The GC-TOF analysis of tar generated from thermal decomposition of PVC evidenced more breakdown of PVC hydrocarbons in the presence of Fe3O4, which led to the enhanced production of syngas. In the presence of 0.01 g Fe₃O₄, the evolution of CO was observed at lower temperature (7.1 mol% at 680 °C) than the case without Fe₃O₄, and further addition of Fe₃O₄ up to 0.5 g gradually increased the CO level in the latter stage of pyrolysis (up to 4.5 mol% at 900 °C), which is attributed to the enhanced Boudouard reaction. Good adsorption ability of biochar products was also demonstrated in the removal of methylene blue. Collectively, the use of Fe₃O₄ in CO₂-assisted pyrolysis of plastics could open the possibility of utilizing waste plastics in thermo-chemical process for energy recovery and environmental application. © 2019 Elsevier B.V.

This work was supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources (Project code: 19-3413 ).