文摘
Nanoscale zerovalent iron, n-ZVI, was found to be highlyeffective in reductively debrominating decabromodiphenylether (BDE209) at ambient conditions and without thecatalysis of noble metals. A method was developed toimmobilize n-ZVI particles on a cation-exchange resin. Then-ZVI coated resin was then mixed with BDE209 in a water/acetone (1:1) solution, and the reaction was allowed toproceed for up to 10 days. The first-order rate constant ofBDE209 disappearance was estimated to be 0.28 ± 0.04h-1. The debromination was found to be stepwise, and less-brominated congeners were produced with increasingreaction time. Dechlorination of decachlorobiphenyl (PCB209)was also investigated, but the reaction rate was muchslower than the debromination of BDE209. Identification ofthe reaction products was highly challenging and wasassisted by regression equations between experimentaland reference gas chromatographic relative retention times,with confirmation by high-resolution mass spectrometryand reference to quantitative structure retention relationships.For randomly selected PBDE and PCB congeners, thenet charges of individual atoms were calculated using thequantum chemical computation to explore the differencein relative vulnerability of halogens at different substitutionpositions between PBDEs and PCBs.