| Edible oils are an essential component of the human dietary,and the safety and quality of the oils have always been of great concern in China and worldwide.Improper temperature control during drying or roasting of oilseeds will lead to partial charring and the production of PAHs.The PAHs have teratogenic,mutagenic and carcinogenic properties and can be distributed to human tissues through various routes such as skin,respiration and ingestion,posing a serious threat to public safety and human health.The adsorption process has been shown to be an effective method for removing PAHs from oils and fats.However,the different adsorbents have distinct pore structures and vary in their adsorption capacity.This study will investigate the effectiveness of different carbon-based adsorbents for the removal of polycyclic aromatic hydrocarbons from edible oils.The individual carbon-based adsorbent materials were modified to enhance the removal efficiency of specific contaminants,increase the adsorption capacity,and protect the nutritional and quality safety of the edible oils,providing a new idea for the application of carbon-based materials in the treatment of edible oils.The major research and conclusions are listed below:(1)The effectiveness of three types of activated carbon,multi-walled carbon nanotubes,graphene and graphene oxide on the removal of PAH4 from peanut oil and the retention of nutrients was investigated.The activated carbons have rough,porous surface structures and abundant surface functional groups which provide strong adsorption of polycyclic aromatic hydrocarbons.In particular,the coconut shell-based activated carbon showed 93.34%removal of PAH4,while wood-based activated carbon had significant advantages in terms of nutrient retention(The V_E content was 152.11μg/g,the phytosterol content was 150.48 mg/100g and the total phenolic content was 25.34 mg/kg).(2)The activated carbon was treated with acid,alkali and surfactant impregnation to investigate the adsorption characteristics of modified activated carbon on PAHs in edible oils.Surfactant-modified activated carbon was found to be outstandingly effective for the adsorption of PAHs from oils and fats.At low levels of addition(0.1%),the prepared AC_y-SDS and AC_y-CTAB were 95.03%and 96.55%effective in the removal of PAH4,respectively.The V_E and total phenol content in peanut oil after surfactant-modified activated carbon treatment were significantly higher than that of acid-modified and alkali-modified.(3)The effect of impregnation treatment by surfactants(CTAB,SDS and Triton X-100)on the structure and adsorption performance of coconut shell activated carbon was investigated.The surfactant-modified coconut shell activated carbon had stronger OH and C=C vibrational peaks,and the removal of PAH4 from peanut oil was maintained at more than 90%.The adsorption of PAH4 on modified coconut shell activated carbon was a spontaneous heat absorption process,and the adsorption isotherms and kinetics were in accordance with the Freundlich and quasi-secondary models.This implies that the adsorption process is born on a non-homogeneous surface and chemisorption controls the overall efficiency of the adsorption process.In addition,the loss of nutrients in the oil was reduced after the modification treatment.In addition,the loss of nutrients in the oil was reduced after the modification treatment.The V_E content of the oil increased by more than 45.00%compared to the coconut shell activated carbon treatment,the pigment content of the oil increased by 78.49%after AC_y-CTAB treatment.Importantly,the adsorbed vegetable oil showed no significant cytotoxicity to human gastric cells.(4)The wood activated carbon was modified with surfactants and its structure and surface morphology were characterized,and its adsorption properties were studied.The surfactant-modified wood activated carbon had a large specific surface area(>1179.05 m~2/g)and pore size(>3.78 nm),and the removal of PAH4 after modification was above 90%.The adsorption of PAH4 by prepared adsorbents all conformed to the Freundlich model,and the thermodynamic and kinetic datas revealed that the process of adsorption of PAH4 is inherently a spontaneous heat absorption process.The phytosterol content in peanut oil increased from150.48 mg/100g to 189.03 mg/100g,186.01 mg/100g and 172.93 mg/100g after AC_m-CTAB,AC_m-SDS and AC_m-Triton X-100 treatments,respectively.The V_E content of peanut oil after AC_m-SDS treatment increased by 19.02%compared to the unmodified wood-activated carbon treatment.In addition,the prepared modified woody activated carbon has low toxicity and the treated peanut oil is safe and non-toxic.In this study,the impact of several carbon-based adsorbents on the adsorption of PAHs and trace reactive substances in edible oils was investigated and activated carbon was found to be superior as a modifier carrier.Activated carbon modified by surfactants has a good adsorption effect on PAHs in peanut oil,and also has some improvement on the loss of nutrients in the oil.This findings from this study provide new ideas for the removal of hazardous substances from edible oils. |
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