Pollution control mechanism analysis of thermal degradation of decabromodiphenyl ether by zinc oxide

Abstract

Low brominated diphenyl ethers and brominated dioxins with high toxicity were easily produced in the pyrolysis process of decabromodiphenyl ethers, Based on this, the pyrolysis process of BDE-209 and ZnO was studied by differential thermal gravimetric analysis (DTA-TG), X-ray diffraction (XRD), GC and GC / MS. The results showed that the addition of zinc oxide reduced the activation energy of BDE-209 thermal degradation reaction, thus reducing the thermal degradation temperature of BDE-209; after the addition of zinc oxide, BDE-209 pyrolysis produced more brominated dioxins at 400 ℃ When BDE-209 and ZnO were degraded at 400 ℃ at 2.4:1 (w / W), the degradation rate reached 100% at 2 h. At this time, the relative content of hexabromo- and heptabromo- dioxins was lower, and the relative content of hexabromobenzene and pentabromobenzene was the highest. Combined with Arrhenius formula calculation, soft and hard acid-base theory and XRD product analysis of pyrolysis residue, the mixed pyrolysis mechanism of BDE-209 and zinc oxide was deeply discussed, which provided a theoretical basis for pollution prevention and control of waste printed circuit boards in heat treatment.