TY - JOUR
T1 - Alkaline reforming of brominated fire-retardant plastics
T2 - Fate of bromine and antimony
AU - Onwudili, Jude A.
AU - Williams, Paul T.
PY - 2009/2/1
Y1 - 2009/2/1
N2 - High-impact polystyrene (HIPS) flame retarded with decabromodiphenyl ether (DDE), has been reacted in supercritical water from 380 to 450 °C and 21.5 to 31.0 MPa pressure in a batch reactor. Different concentrations of sodium hydroxide additive were used in situ to neutralize the corrosive inorganic bromine species released during the reactions. It appeared that supercritical water conditions lowered the decomposition temperature of both the fire-retardant DDE and HIPS. The reaction products included oils (up to 76 wt%), char (up to 18 wt%) and gas (up to 2.4 wt%) which was mainly methane. The presence of the alkaline water led to up to 97 wt% debromination of the product oil, producing virtually bromine-free oil feedstock. The removal of antimony from the oil product during processing was of the order of 98 wt%. The oil consisted of many single- and multiple-ringed aromatic compounds, many of which had alkyl substituents and/or aliphatic Cn-bridges (n = 1-4). The major single-ringed compounds included toluene, xylenes, ethylbenzene, propylbenzene and α-methylstyrene. Bibenzyl (diphenylethane), stilbene, diphenylmethane, diphenylpropane, diphenylcyclopropane, diphenylpropene, diphenylbutane, diphenylbutene and diphenylbuta-1,3-diene were the major Cn-bridged compounds. Diphenyl ether and acetophenone were the major oxygenated compounds found. The process thus has the potential to produce bromine-free and antimony-free oils from fire-retardant plastics.
AB - High-impact polystyrene (HIPS) flame retarded with decabromodiphenyl ether (DDE), has been reacted in supercritical water from 380 to 450 °C and 21.5 to 31.0 MPa pressure in a batch reactor. Different concentrations of sodium hydroxide additive were used in situ to neutralize the corrosive inorganic bromine species released during the reactions. It appeared that supercritical water conditions lowered the decomposition temperature of both the fire-retardant DDE and HIPS. The reaction products included oils (up to 76 wt%), char (up to 18 wt%) and gas (up to 2.4 wt%) which was mainly methane. The presence of the alkaline water led to up to 97 wt% debromination of the product oil, producing virtually bromine-free oil feedstock. The removal of antimony from the oil product during processing was of the order of 98 wt%. The oil consisted of many single- and multiple-ringed aromatic compounds, many of which had alkyl substituents and/or aliphatic Cn-bridges (n = 1-4). The major single-ringed compounds included toluene, xylenes, ethylbenzene, propylbenzene and α-methylstyrene. Bibenzyl (diphenylethane), stilbene, diphenylmethane, diphenylpropane, diphenylcyclopropane, diphenylpropene, diphenylbutane, diphenylbutene and diphenylbuta-1,3-diene were the major Cn-bridged compounds. Diphenyl ether and acetophenone were the major oxygenated compounds found. The process thus has the potential to produce bromine-free and antimony-free oils from fire-retardant plastics.
KW - Plastics
KW - Reforming
KW - Supercritical water
KW - Waste
UR - http://www.scopus.com/inward/record.url?scp=58549088681&partnerID=8YFLogxK
UR - https://www.sciencedirect.com/science/article/pii/S004565350801326X?via%3Dihub
U2 - 10.1016/j.chemosphere.2008.10.029
DO - 10.1016/j.chemosphere.2008.10.029
M3 - Article
C2 - 19054543
AN - SCOPUS:58549088681
SN - 0045-6535
VL - 74
SP - 787
EP - 796
JO - Chemosphere
JF - Chemosphere
IS - 6
ER -