Optimization of activated carbon‐based decontamination of fish oil by response surface methodology

Abstract

The effect of activated carbon (AC) adsorption on the reduction of persistent organic pollutants (POP) in fish oil was studied based on response surface methodology at a 5-g/kg AC inclusion level. Pretreatment of the oil by alkali refining and bleaching increased the POP levels. The tested process variables (contact time and temperature) affected the AC adsorption rate and significant first-and second-order response models could be established. Polychlorinated dibenzo-pdioxins and dibenzofurans (PCDD/F) showed a very rapid adsorption behavior and the concentration and toxic equivalent (TEQ) level could be reduced by 99%. Adsorption of dioxin-like polychlorinated biphenyls (DL-PCB) was less effective and depended on ortho substitution, i.e. non-ortho PCB were adsorbed more effectively than mono-ortho PCB with a maximum of 87 and 21% reduction, respectively, corresponding to a DL-PCB-TEQ reduction of 73%. A common optimum for both PCDD/F and DL-PCB adsorption could not be identified. AC treatment had no effect on the level of polybrominated diphenyl ether flame retardants. The differences in adsorption patterns may be explained based on molecular conformation. No change in oil quality could be observed based on oxidation parameters. Compliance with present PCDD/F and DL-PCB legislation levels in fish oil can be achieved based on AC adsorption.

Molecular dynamics study of selective adsorption of PCB on activated carbon

“…This system was simulated for an extended time in order to reduce the memory of initial state. The temperature was then scaled down to 330K, to reproduce the mean experimental temperature used in Oterhals et al [1].…”

“…Polychlorinated polychlorinated biphenyls (PCB) together with dibenzop-dioxins and dibenzofurans (PCDD/F) are classified as persistent organic pollutants (POPs), known to bioaccumulate in the food chain [1]. Fish oil produced from pelagic fish and their by-products is used as polyunsaturated ω-3 fatty acid source in compounded feeds.…”

“…Fish oil produced from pelagic fish and their by-products is used as polyunsaturated ω-3 fatty acid source in compounded feeds. High inclusion levels make it the main POP contributor in Atlantic salmon feed [1][2][3]. The level of POPs in North European fish stocks are generally higher than in the South Pacific ones, putting the fish-processing industry in the region at a distinct disadvantage since parts of their fish oil and fishmeal products need to be purified to comply with the maximum permitted levels [1,4].…”

“…High inclusion levels make it the main POP contributor in Atlantic salmon feed [1][2][3]. The level of POPs in North European fish stocks are generally higher than in the South Pacific ones, putting the fish-processing industry in the region at a distinct disadvantage since parts of their fish oil and fishmeal products need to be purified to comply with the maximum permitted levels [1,4]. The POPs level in produced fish oil will depend on the pollution status in the respective fishing areas and seasonal variation in the fat content of the fish [1,4].…”

“…It has been shown in previous research [1] that adsorption onto activated carbon is a viable option for PCDD/F removal, but is much less effective when it comes to PCB reduction. A wide variation in the efficiency of the activated carbon adsorption process for different PCB congeners has also been observed in a process optimization study by Oterhals et al based on alkali-refined and bleached fish oil.…”