Extraction of brominated flame retardants from polymeric waste material using different solvents and supercritical carbon dioxide

Abstract

Different procedures were examined to extract pure and high concentrations of a series of brominated flame retardants from various polymer materials. These procedures include supercritical carbon dioxide (sc-CO 2), modified sc-CO 2, solvent and soxhlet extraction. Extraction with sc-CO 2 gave low extraction efficiencies (between 6 and 20%) probably due to the low pressure of sc-CO 2 used. The use of toluene, acetonitrile and THF as modifier in sc-CO 2 raised the extraction efficiencies for many flame retardants. High extraction efficiencies were achieved for tetrabromobisphenol A (TBBPA), TBBPA-bis-(2,3-dibromopropylether) (TBBPA-dbp), TBBPA-carbonatoligomer (TBBPA-co) and decabromodiphenylether (DECA) (between 93 and 100%) by using 1-propanol as solvent during soxhlet extraction. Toluene instead of 1-propanol was used where insufficient extraction of the flame retardant occurred. The materials (before and after extraction) were analysed with energy dispersive X-ray fluorescence analysis (EDXRF), high performance liquid chromatography with ultraviolet detection (HPLC/UV), gas chromatography/mass spectrometry (GC/MS) and infrared spectroscopy (IR) techniques. The properties of the extracted flame retardants such as TBBPA, TBBPA-dbp and 1,2-bis(tribromophenoxy)-ethane (TBPE) are in good agreement with those of standard reference materials.