Experimental Study on the Removal of Dioxins and Coplanar Polychlorinated Biphenyls (PCBs) from Fish Oil

Recently, it has been found that fish oils contain a high proportion of contaminants, namely, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (cPCBs). In this study, the removal of contaminants from fish oil by supercritical CO2 extraction (SCE) and by using adsorbents (0.13 wt % of oil) was investigated. Dioxins and cPCBs were extracted from fish oil by SCE at a temperature of 60 °C and a pressure of 28 MPa, and the removal efficiencies for PCDDs and PCDFs were in the range of 15−90% and those for cPCBs were in the range of 70−90%. However, 40% of the oil was extracted simultaneously with contaminants. On the adsorbent treatment, activated carbon showed high efficiency, and the removal efficiencies were >90% for PCDDs and PCDFs, but below 30% for cPCBs. A combination of both of these methods is more effective, and almost 100% of the total toxicity equivalence quantity value could be reduced. Keywords: Fish oil; dioxins; supercritical CO2; extraction; activated carbon