Extraction of Polybrominated Diphenyl Ethers from Plastic Solution by Supercritical Carbon Dioxide Anti-Solvent

A new recycling process on supercritical CO2 extraction of PBDEs from waste HIPS plastic was developed in this paper, the influence laws of temperature, pressure, volume of supercritical CO2 and deca-BDE concentration on the separating efficiency were investigated, the measures for reducing the effect of deca-BDE concentration on the separating efficiency were proposed. The experimental results showed that the suitable supercritical condition was 65 °C, 20MPa, the optimum volume ratio of supercritical CO2 to HIPS solution was 2:1, and the deca-BDE particles can be removed by a centrifuge process at speed of 10000 r/min and at 30 °C. It was found that over 97% of PBDEs was successfully removed and the concentration of PBDEs residual in HIPS was reduced to lower than 0.1% (dry) by this recycling process.