Preparation Of Electrospinning Composite Membrane And Study On Its Adsorption Technology For Hazard Factors In Food

Food safety has always been a hot issue.Nowadays,the abuse of antibiotics and the occurrence of mycotoxin pollution events have brought potential hazards to food safety.Therefore,the development of technology to remove pollutants in food is of great significance for maintaining national food safety and ensuring people’s health.Electrospinning fibers are widely used in the fields of environment,food and biomedical engineering due to their biodegradability,low cost and high porosity.Combining it with molecularly imprinted polymers and endowing them with specific binding sites can identify and bind the target molecules with high affinity.Covalent Organic Frameworks have the advantages of large specific surface area and good thermal stability.The adsorption effect can be greatly improved by combining them with electrospinning fibers.Therefore,electrospinning fiber-surface molecularly imprinted polymer composite and electrospinning fiber-COF composite were prepared in this study to achieve efficient adsorption and removal of Chloramphenicol and Aflatoxin B₁,respectively.The main results were as follows:（1）In this study,CAP molecularly imprinted polymer with core-shell structure was prepared by surface imprinting method using amino silica microspheres as a carrier.The morphology,adsorption performance and stability of the material were studied.The results showed that the adsorption rate of Si O₂-NH₂@MIP for CAP was fast,and the adsorption capacity was 65.36 mg/g,which was a monolayer chemical adsorption.After five cycles,the adsorption rate could still reach more than 94%.Adsorption membrane was prepared by electrospinning fiber membrane as carrier combined with molecularly imprinted polymers.The prepared imprinted and non-imprinted fiber membranes still have adsorption differences and good separation effect,which solves the problem of difficult separation and secondary pollution of powdered polymers.（2）In this study,based on the first experiment,COF with large specific surface area and good thermal stability was selected to grow in situ on the fiber membrane.Firstly,2,5-divinyl terephthalaldehyde was mixed with polyacrylonitrile spinning solution to provide growth sites for the formation of COF.PAN/DVA was prepared by electrospinning,and then PAN@COF fiber membrane was prepared by growing“flower-like”COF,which was used to remove aflatoxin B₁.The characterization,adsorption properties and adsorption mechanism of the prepared materials showed that the activated PAN@COF could adsorb AFB₁ for 30 min,the adsorption capacity is 30.98 mg/g,and the adsorption membrane could be reused after washing in alkaline solution.The removal rate was still above 98%after 10cycles,mainly through hydrogen bonding,π-πstacking and hydrophobic force.Compared with the previous method,the adsorption site is completely exposed,the specific surface area is larger,and the adsorption efficiency is greatly improved.In this paper,based on electrospinning technology,PAN/Si O₂-NH₂@MIP adsorption membrane that can specifically bind CAP and PAN@COF that can effectively remove AFB₁were prepared by blending method and in-situ growth method,respectively.Both of them showed excellent membrane performance and had the potential to be used as an environmentally friendly filter membrane for removing pollutants in food.