Recycling of WEEE plastics: a review

Buekens, Alfons; Yang, Jie

doi:10.1007/s10163-014-0241-2

Cited by 183 publications

(118 citation statements)

References 63 publications

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“…Recycling WEEE is important, not only to reduce the amount of waste requiring treatment, but also to encourage the recovery of raw materials contained in this kind of equipment, such as plastics, base metals (copper, tin), and precious metals (gold, silver, platinum), as well as to eliminate responsibly its environmentally dangerous compounds such as brominated flame retardants and heavy metals (Buekens and Yang, 2014). WEEE can be a serious threat to human health (Leung et al, 2008) and the environment (Owens et al, 2007) if they are not properly treated.…”

Section: Introductionmentioning

confidence: 99%

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

2017

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Degradation of brominated flame retardants present in printed circuit boards (PCBs) was tested using subcritical water in a high pressure reactor. Debromination experiments were carried out in a batch stirred reactor at three different temperatures (225 ºC, 250 ºC and 275 ºC) keeping a solid to liquid (S/L) ratio of PCB:water=1:5 during 180 min. Results indicated that debromination efficiency was increased with temperature (18.5 to 63.6% of bromine present in the original PCB was removed).Thermal decomposition of the debrominated materials was studied and compared with that of the original PCB. Thermogravimetric analyses were performed at three different heating rates (5, 10 and 20 K min -1 ), studying both the pyrolysis (inert atmosphere) and combustion (in air). Pyrolysis runs of the debrominated materials were also performed in a quartz horizontal laboratory furnace at 850 ºC, in order to study the emission of pollutants. More than 99% of the bromine was emitted in the form of HBr and Br 2 . Emissions of polycyclic aromatic hydrocarbons (PAHs) and bromophenols (BrPhs) decreased with the increase in the treatment temperature; naphthalene (10800 -18300 mg kg -1 original sample) and monobrominated phenols (12.8 -16.9 mg kg -1 original sample) were the most abundant compounds.

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Section: Introductionmentioning

confidence: 99%

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

2017

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“…In 2014, according to United Nations University report 29 (Baldé et al, 2015), 41.8 million tonnes of WEEE were produced worldwide. WEEE is 30 composed of numerous materials, from recyclable raw materials such as plastics and metals 31 (Cu, Al, Fe, Sn, Co, In, Sb and precious metals like Ag, Au, Pd and Pt) and hazardous products 32 such as heavy metals (Cd, Hg, Pb and Ni) and halogenated (mainly brominated) flame 33 retardants (Buekens and Yang, 2014). Consequently, WEEE represents a hazard to human life 34 and the environment if not properly treated.…”

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confidence: 99%

Pollutant formation in the pyrolysis and combustion of materials combining biomass and e-waste

Soler

Conesa

Íñiguez

et al. 2018

Science of The Total Environment

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Combustion and pyrolysis runs at 850 ºC were carried out in a laboratory scale horizontal 10 reactor with different materials combining biomass and waste electrical and electronic 11 equipment (WEEE). Analyses are presented of the carbon oxides, light hydrocarbons, 12 polycyclic aromatic hydrocarbons (PAHs), polychlorinated benzenes (ClBzs), polychlorinated 13 phenols (ClPhs), polybrominated phenols (BrPhs), polychlorinated dibenzo-p-dioxins and 14 dibenzofurans (PCDD/Fs). Results showed that gas emissions were mainly composed of CO 15 and CO 2 ; the high level of CO found in the pyrolytic runs was easily transformed into CO 2 by 16 reaction with oxygen. The total amount of light hydrocarbons emitted was somewhat higher in 17 the samples containing WEEE, methane being the most abundant light hydrocarbon in all the 18 runs. However, the presence of WEEE reduced the emission of PAHs which clearly decreased 19 with the increase of the oxygen. The total amount of BrPhs increased in the decomposition of 20 the samples containing WEEE, reaching its maximum in pyrolysis runs. Emission of PCDD/Fs 21 was enhanced in pyrolytic conditions and they were easily destroyed in the presence of oxygen. 22 23

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“…Thermal treatment of the ever increasing electronic and electric waste (e-waste) constitutes a real-world case where the recycling of bromine and extraction of metals overlap. 1 The non-metallic fraction in e-waste bears a significant load of halogenated hydrocarbons, mainly in the form of brominated flame retardants (BFRs). [1][2][3][4][5] On the other hand, exposing the metallic constituents in e-waste to oxygen at elevated temperature transforms them readily into metal oxides.…”

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confidence: 99%

Thermal Recycling of Brominated Flame Retardants with Fe₂O₃

et al. 2016

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Results from this study provide an atomic-based insight into a promising thermal recycling route of e-waste. Page 2 of 33 ACS Paragon Plus EnvironmentThe Journal of Physical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 3 IntroductionCo-pyrolysis of metal oxides with halogen-bearing materials attracts technological interests on two compelling grounds: (i) recycling of bromine and chlorine-containing objects and (ii)pyro-metallurgical extraction of metals from their oxides. Thermal treatment of the ever increasing electronic and electric waste (e-waste) constitutes a real-world case where the recycling of bromine and extraction of metals overlap. 1 The non-metallic fraction in e-waste bears a significant load of halogenated hydrocarbons, mainly in the form of brominated flame retardants (BFRs). [1][2][3][4][5] On the other hand, exposing the metallic constituents in e-waste to oxygen at elevated temperature transforms them readily into metal oxides. 3 The interest in studying the co-pyrolysis of BFRs with metal oxides stems from their ability to act as bromine fixation agents, 6 the process that ultimately leads to reductive debromination of BFRs. Of particular industrial as well as health importance are ferric oxides that make up most of the ferric fraction in electric arc furnace dust (EAFD). It is estimated that, 4.3 -5.7 million tonnes of EAFD arise annually worldwide during crude steel production. 7 Thermal degradation of BFRs in the presence of metal oxides achieves a dual-benefit, reducing the overall toxicity of the decomposition products of BFRs and forming metal bromides that could be easily leached out.The potential for the conversion of BFRs into hazardous brominated compounds (most notably the notorious polybrominated dibenzo-p-dioxins and furans, PBDD/Fs) often overshadows the environmental and economic benefits of thermal recycling of e-waste. 8, 9The co-existence of aromatic brominated precursors with metal oxides typically act as a perfect recipe for the catalytic synthesis of PBDD/Fs through prominent intermediate steps. 10While HCl represents an inactive chlorinating agent for generation of PCDD/Fs, 11 conversionPage 3 of 33 ACS Paragon Plus EnvironmentThe Journal of Physical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 We estimate reaction rate constants based on the conventional transition state theory (TST).In the TST calculations, vibrational frequencies yield activation enthalpies and entropies at the temperature of interest (300 -1000 K). A-factors for barrierless reactions are estimated based on the difference in entropies between reactants and products. We report electronic charges for the α-Fe 2 O 3 cl...

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Recycling of WEEE plastics: a review

Cited by 183 publications

References 63 publications

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

Pollutant formation in the pyrolysis and combustion of materials combining biomass and e-waste

Thermal Recycling of Brominated Flame Retardants with Fe₂O₃

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Recycling of WEEE plastics: a review

Cited by 183 publications

References 63 publications

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

Pollutant formation in the pyrolysis and combustion of materials combining biomass and e-waste

Thermal Recycling of Brominated Flame Retardants with Fe2O3

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Thermal Recycling of Brominated Flame Retardants with Fe₂O₃