title: Simultaneous recovery of benzene-rich oil and metals by steam pyrolysis of metal-poly(ethylene terephthalate) composite waste.
abstract: The possibility of simultaneous recovery of benzene and metals from the hydrolysis of poly(ethylene terephthalate) (PET)-based materials such as X-ray films, magnetic tape, and prepaid cards under a steam atmosphere at a temperature of 450 °C was evaluated. The hydrolysis resulted in metal-containing carbonaceous residue and volatile terephthalic acid (TPA). The effects of metals and additives on the recovery process were also investigated. All metals were quantitatively recovered, and silver, maghemite (γ-Fe2O3), and anatase (TiO2) were recovered without any changes in their crystal structures or compositions. In a second step, TPA was decarboxylized in the presence of calcium oxide (CaO) at 700 °C, producing benzene with an average yield of 34% and purity of 76%. Maghemite (γ-Fe2O3) incorporated in magnetic tape and prepaid cards could decarboxylate TPA. Aluminum present in the prepaid cards produced hydrogen by the reaction with steam. However, the presence of metals had no adverse influence on the recovery of benzene-rich oil in the presence of CaO. Therefore, this method can be applied to PET-based materials containing inorganic substances, which cannot be recycled effectively otherwise.
authors: Graduate School of Environmental Studies, Tohoku University , 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
authors: Shogo
authors: S
authors: Kumagai
authors: Guido
authors: G
authors: Grause
authors: Tomohito
authors: T
authors: Kameda
authors: Toshiaki
authors: T
authors: Yoshioka
mesh_terms: D001554:Benzene / Q000737:chemistry*; D006358:Hot Temperature; D019216:Metals, Heavy / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry; D010795:Phthalic Acids / Q000737:chemistry; D011093:Polyethylene Terephthalates / Q000737:chemistry*; D059027:Recycling / Q000379:methods*; D012037:Refuse Disposal; D013227:Steam
chemical_list: D019216:Metals, Heavy; D010087:Oxides; D010795:Phthalic Acids; D011093:Polyethylene Terephthalates; D013227:Steam; C011363:terephthalic acid; D001554:Benzene