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-<i>p</i>-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