Rate of hexabromocyclododecane decomposition and production of brominated polycyclic aromatic hydrocarbons during combustion in a pilot-scale incinerator
Yuichi Miyake , Masahiro Tokumura , Qi Wang , Takashi Amagai , Yuichi Horii
DOI:10.1016/j.jes.2017.07.007
Received December 29, 2016,Revised June 28, 2017, Accepted July 07, 2017, Available online July 15, 2017
Volume 29,2017,Pages 91-96
Here, we examined the incineration of extruded polystyrene containing hexabromocyclododecane (HBCD) in a pilot-scale incinerator under various combustion temperatures (800–950°C) and flue gas residence times (2–8 sec). Rates of HBCD decomposition ranged from 99.996% (800°C, 2 sec) to 99.9999% (950°C, 8 sec); the decomposition of HBCD, except during the initial stage of combustion (flue gas residence time < 2 sec), followed a pseudo-first-order kinetics model. An Arrhenius plot revealed that the activation energy and frequency factor of the decomposition of HBCD by combustion were 14.2 kJ/mol and 1.69 sec? 1, respectively. During combustion, 11 brominated polycyclic aromatic hydrocarbons (BrPAHs) were detected as unintentional by-products. Of the 11 BrPAHs detected, 2-bromoanthracene and 1-bromopyrene were detected at the highest concentrations. The mutagenic and carcinogenic BrPAHs 1,5-dibromoanthracene and 1-bromopyrene were most frequently detected in the flue gases analyzed. The total concentration of BrPAHs exponentially increased (range, 87.8–2,040,000 ng/m3) with increasing flue gas residence time. Results from a qualitative analysis using gas chromatography/high-resolution mass spectrometry suggest that bromofluorene and bromopyrene (or fluoranthene) congeners were also produced during the combustion.
