Hydrothermal decomposition of brominated epoxy resin in waste printed circuit boards

Brominated flame retardant (BFR), which containing in printed circuit boards (WPCBs), brings a series of environmental and health problems. Hydrothermal technology was applied to decompose brominated epoxy resin in WPCBs at subcritical or supercritical water conditions. The brominated epoxy resin was decomposed into oil and the environmental influence of BFR was eliminated. The experiment was carried out in a 5.7 ml tube reactor and heated by a salt-bath. The variation of degradation rate of brominated epoxy resin with reaction temperature, time and additives were studied. The compositions of liquid products were analyzed by gas chromatography–mass spectrometry (GC–MS). When reaction temperature exceeded 300 °C, retention time stayed over 30 min and alkaline additive existed, more than 80% brominated epoxy resin could be mainly decomposed into phenol, which can be used as chemical material. Two different hydrothermal decomposition pathways were discussed according to the characterization of products. The results indicated that brominated epoxy resin in WPCBs could be handled effectively by hydrothermal decomposition.