Kinetic parameters underlying hematite-assisted decomposition of tribromophenol

Interaction of brominated flame retardants (BFRs) and transition metal oxides is a widely utilized approach in thermal recycling of bromine-contaminated plastics. An optimum design of the operation requires the development of accurate thermo-kinetic parameters that dictate the co-degradation of both entities. To attain this obviative, thermal degradation behavior pertinent to co-pyrolysis and co-combustion of hematite (Fe2O3): tribromophenol (TBP) mixtures was explored in a thermogravimetric analyzer (TGA) at various heating rates. Thermo-kinetic parameters for mixtures were acquired based on TGA runs while employing three major model-free or isoconversional methods (KAS, Starink, and FWO) and model-fitting methods (Coats-Redfern). Obtained profiles infer that the addition of hematite systematically reduces the governing activation energy (Ea) in both thermochemical processes in reference to neat TBP. The hematite-assisted debromination of TBP under oxidative conditions entails lower activation energy when compared with degradation under pyrolytic conditions. Molecular modeling mapped out initial mechanisms that operate in the interaction with a prime focus on reactions that lead to ring opening of the aromatic rings. Overall, the results obtained from the thermal chemical conversions find direct application in reactor modeling and heat transfer design in domains related to the recycling of electronic and electrical waste (e-wastes). (c) 2023 The Authors. Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The interaction between brominated flame retardants (BFRs) and transition metal oxides is widely used in the thermal recycling of bromine-contaminated plastics. This study investigated the thermal degradation behavior of hematite (Fe2O3): tribromophenol (TBP) mixtures during co-pyrolysis and co-combustion using a thermogravimetric analyzer (TGA). The obtained thermo-kinetic parameters provide insights into the reduction of activation energy by hematite and the mechanism of debromination of TBP. The results have direct applications in reactor modeling and heat transfer design for the recycling of electronic waste.