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Co-pyrolysis of polyethylene with products from thermal decomposition of brominated flame retardants


Altarawneh, Mohammednoor and Ahmed, Oday H. and Al-Harahsheh, Mohammad and Jiang, Zhong Tao and Nay, Ming Huang and Lim, Hong Ngee and Dlugogorski, Bogdan Z. (2020) Co-pyrolysis of polyethylene with products from thermal decomposition of brominated flame retardants. Chemosphere, 254. art. no. 126766. pp. 1-9. ISSN 0045-6535; ESSN: 1879-1298


Co-pyrolysis of brominated flame retardants (BFRs) with polymeric materials prevails in scenarios pertinent to thermal recycling of bromine-laden objects; most notably the non-metallic fraction in e-waste. Hydro-dehalogenation of aromatic compounds in a hydrogen-donating medium constitutes a key step in refining pyrolysis oil of BFRs. Chemical reactions underpinning this process are poorly understood. Herein, we utilize accurate density functional theory (DFT) calculations to report thermo-kinetic parameters for the reaction of solid polyethylene, PE, (as a surrogate model for aliphatic polymers) with prime products sourced from thermal decomposition of BFRs, namely, HBr, bromophenols; benzene, and phenyl radical. Facile abstraction of an ethylenic H by Br atoms is expected to contribute to the formation of abundant HBr concentrations in practical systems. Likewise, a relatively low energy barrier for aromatic Br atom abstraction from a 2-bromophenol molecule by an alkyl radical site, concurs with the reported noticeable hydro-debromination capacity of PE. Pathways entailing a PE-induced bromination of a phenoxy radical should be hindered in view of high energy barrier for a Br transfer into the para position of the phenoxy radical. Adsorption of a phenoxy radical onto a Cu(Br) site substituted at the PE chain affords the commonly discussed PBDD/Fs precursor of a surface-bounded bromophenolate adduct. Such scenario arises due to the heterogeneous integration of metals into the bromine-rich carbon matrix in primitive recycling of e-waste and their open burning.

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Additional Metadata

Item Type: Article
Divisions: Faculty of Science
DOI Number: https://doi.org/10.1016/j.chemosphere.2020.126766
Publisher: Elsevier
Keywords: Polymeric materials; Brominated flame retardants; Reaction mechanism; Co-pyrolysis
Depositing User: Ms. Nuraida Ibrahim
Date Deposited: 10 Mar 2022 02:55
Last Modified: 24 Nov 2022 04:40
Altmetrics: http://www.altmetric.com/details.php?domain=psasir.upm.edu.my&doi=10.1016/j.chemosphere.2020.126766
URI: http://psasir.upm.edu.my/id/eprint/88271
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