title: Thermochemical behavior of tris(2-butoxyethyl) phosphate (TBEP) during co-pyrolysis with biomass.
abstract: Co-pyrolysis of plastic waste and wood biomass to recover valuable chemicals is a cost-effective waste-recycling technology. However, widely used organophosphate ester additives in plastic, such as tris(2-butoxyethyl) phosphate (TBEP), can form diverse phosphorus (P)-containing species. These P-containing compounds can pose new environmental challenges when the biochar is reused. In this study, a mixture of TBEP and lignin was used to simulate the feedstock of plastic waste and wood biomass, and the thermochemical behavior of TBEP in slow pyrolysis (20 K min(-1)) and fast pyrolysis at 400-600 °C was investigated. The results show that low temperature in fast pyrolysis favors the enrichment of P in char. Up to 76.6% of initial P in the feedstock is retained in the char resulting from 400 °C, while only 51% is retained in the char from 600 °C. Slow pyrolysis favors the formation of stable P species regardless of the temperature; only 7% of the P retained in the char is extractable from char from slow pyrolysis, while 20-40% of P can be extracted from char resulting from fast pyrolysis. The addition of CaCl2 and MgCl2 can significantly increase the fraction of P retained in the char by the formation of Ca, Mg-P compounds. Online TG-FTIR-MS analysis suggests that TBEP undergoes decomposition through different temperature-dependent pathways. The P-containing radicals react with the aromatic rings produced by the pyrolysis of lignin to form Ar-P species, which is an important factor influencing the distribution and stabilization of P in char.
authors.affiliation: Department of Chemistry, University of Science and Technology of China , Hefei 230026, People's Republic of China.
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Qian
authors.forename: De-Chang
authors.initials: DC
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
mesh_terms: D018533:Biomass; D002606:Charcoal / Q000737:chemistry; D004777:Environment; D008031:Lignin / Q000737:chemistry*; D013058:Mass Spectrometry; D010755:Organophosphates; D009943:Organophosphorus Compounds / Q000737:chemistry*; D010758:Phosphorus / Q000032:analysis; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D010755:Organophosphates; D009943:Organophosphorus Compounds; D012996:Solutions; C540010:biochar; C012085:tris(2,3-dibromopropyl)phosphate; D002606:Charcoal; D010758:Phosphorus; D008031:Lignin; C013320:tris(2-butoxyethyl) phosphate