TY - JOUR
T1 - Degradation of tetrabromobisphenol A (TBBA) with calcium hydroxide
T2 - a thermo-kinetic analysis
AU - Ali, Labeeb
AU - Sivaramakrishnan, Kaushik
AU - Kuttiyathil, Mohamed Shafi
AU - Chandrasekaran, Vignesh
AU - Ahmed, Oday H.
AU - Al-Harahsheh, Mohammad
AU - Altarawneh, Mohammednoor
N1 - Funding Information:
This study has been supported by the 2019 Abu Dhabi Award for Research Excellence (AARE) – (by ASPIRE, part of the Advanced Technology Research Council (ATRC, Abu Dhabi, United Arab Emirates), grant number: 21N225-AARE2019 – ADEK-103). DFT calculations were carried out at the HCP cluster of the United Arab Emirates University (UAEU).
Funding Information:
This study has been supported by the 2019 Abu Dhabi Award for Research Excellence (AARE) - (by ASPIRE, part of the Advanced Technology Research Council (ATRC, Abu Dhabi, United Arab Emirates), grant number: 21N225-AARE2019 - ADEK-103). DFT calculations were carried out at the HCP cluster of the United Arab Emirates University (UAEU).
Publisher Copyright:
© 2023 The Royal Society of Chemistry.
PY - 2023/2/28
Y1 - 2023/2/28
N2 - Thermal treatment of bromine-contaminated polymers (i.e., as in e-waste) with metal oxides is currently deployed as a mainstream strategy in recycling and resources recovery from these objects. The underlying aim is to capture the bromine content and to produce pure bromine-free hydrocarbons. Bromine originates from the added brominated flame retardants (BFRs) to the polymeric fractions in printed circuits boards, where tetrabromobisphenol A (TBBA) is the most utilized BFR. Among notable deployed metal oxides is calcium hydroxide, i.e., Ca(OH)2 that often displays high debromination capacity. Comprehending thermo-kinetic parameters that account for the BFRs:Ca(OH)2 interaction is instrumental to optimize the operation at an industrial scale. Herein, we report comprehensive kinetics and thermodynamics studies into the pyrolytic and oxidative decomposition of a TBBA:Ca(OH)2 mixture at four different heating rates, 5, 10, 15, and 20 °C min−1, carried out using a thermogravimetric analyser. Fourier Transform Infrared Spectroscopy (FTIR) and a carbon, hydrogen, nitrogen, and sulphur (CHNS) elemental analyser established the vibrations of the molecules and carbon content of the sample. From the thermogravimetric analyser (TGA) data, the kinetic and thermodynamic parameters were evaluated using iso-conversional methods (KAS, FWO, and Starink), which were further validated by the Coats-Redfern method. The computed activation energies for the pyrolytic decomposition of pure TBBA and its mixture with Ca(OH)2 reside in the narrow ranges of 111.7-112.1 kJ mol−1 and 62.8-63.4 kJ mol−1, respectively (considering the various models). Obtained negative ΔS values suggest the formation of stable products. The synergic effects of the blend exhibited positive values in the low-temperature ranges (200-300 °C) due to the emission of HBr from TBBA and the solid-liquid bromination process occurring between TBBA and Ca(OH)2. From a practical point of view, data provided herein are useful in efforts that aim to fine-tune operational conditions encountered in real recycling scenarios, i.e., in co-pyrolysis of e-waste with Ca(OH)2 in rotary kilns.
AB - Thermal treatment of bromine-contaminated polymers (i.e., as in e-waste) with metal oxides is currently deployed as a mainstream strategy in recycling and resources recovery from these objects. The underlying aim is to capture the bromine content and to produce pure bromine-free hydrocarbons. Bromine originates from the added brominated flame retardants (BFRs) to the polymeric fractions in printed circuits boards, where tetrabromobisphenol A (TBBA) is the most utilized BFR. Among notable deployed metal oxides is calcium hydroxide, i.e., Ca(OH)2 that often displays high debromination capacity. Comprehending thermo-kinetic parameters that account for the BFRs:Ca(OH)2 interaction is instrumental to optimize the operation at an industrial scale. Herein, we report comprehensive kinetics and thermodynamics studies into the pyrolytic and oxidative decomposition of a TBBA:Ca(OH)2 mixture at four different heating rates, 5, 10, 15, and 20 °C min−1, carried out using a thermogravimetric analyser. Fourier Transform Infrared Spectroscopy (FTIR) and a carbon, hydrogen, nitrogen, and sulphur (CHNS) elemental analyser established the vibrations of the molecules and carbon content of the sample. From the thermogravimetric analyser (TGA) data, the kinetic and thermodynamic parameters were evaluated using iso-conversional methods (KAS, FWO, and Starink), which were further validated by the Coats-Redfern method. The computed activation energies for the pyrolytic decomposition of pure TBBA and its mixture with Ca(OH)2 reside in the narrow ranges of 111.7-112.1 kJ mol−1 and 62.8-63.4 kJ mol−1, respectively (considering the various models). Obtained negative ΔS values suggest the formation of stable products. The synergic effects of the blend exhibited positive values in the low-temperature ranges (200-300 °C) due to the emission of HBr from TBBA and the solid-liquid bromination process occurring between TBBA and Ca(OH)2. From a practical point of view, data provided herein are useful in efforts that aim to fine-tune operational conditions encountered in real recycling scenarios, i.e., in co-pyrolysis of e-waste with Ca(OH)2 in rotary kilns.
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U2 - 10.1039/d2ra08223c
DO - 10.1039/d2ra08223c
M3 - Article
AN - SCOPUS:85149724589
SN - 2046-2069
VL - 13
SP - 6966
EP - 6982
JO - RSC Advances
JF - RSC Advances
IS - 10
ER -