Abstract
This article elucidates pyrolysis reaction pathways of waste epoxy-printed circuit boards (e-PCBs). Non-isothermal thermogravimetric analyses showed that waste e-PCBs decomposed via a series of reactions distinguished by three apparent reaction regions. The first-stage reaction (<250 C) can be accounted for by the cleavage reaction of N-containing cross-linkage between brominated epoxy resin (BER) and non-brominated epoxy resin (NBER). Evolved gas analysis-mass spectrometry (EGA-MS) showed that the second-stage reaction (250-500 C) can be represented by two independent decomposition reactions of BERs and NBERs to yield thermally stable intermediates. BERs decomposed more rapidly (250-350 C), whereas NBERs decomposed over broader temperature regions (250-500 C) with slower decomposition rates. Multi-shot gas chromatography/mass spectrometry also indicated that brominated compounds, brominated phenol and brominated bisphenol A, are generated mainly at lower temperature zones of the second-stage region, whereas phenols and branched phenols are generated at higher temperature zones. Steady but slow conversion of intermediates was carried out over the conversion of 0.9. At the third-stage reaction, thermally stable intermediates were converted slowly to char as a result of HBr release from intermediates.
| Original language | English |
|---|---|
| Pages (from-to) | 706-712 |
| Number of pages | 7 |
| Journal | Environmental Engineering Science |
| Volume | 30 |
| Issue number | 11 |
| DOIs | |
| State | Published - 1 Nov 2013 |
Keywords
- Py-GC/MS
- TGA
- independent reaction
- pyrolysis reaction pathway
- series reaction
- waste e-PCB