Study On The G-C₃N₄-Plasma Nanofibers With Double Functions Of Pesticide Degradation And Antibacterial Preservation

Fresh vegetables are an indispensable part of daily diet because they rich in multiple essential nutrients in human body.With the consciousness of food safety strengthening,pathogenic microorganism contamination and pesticide residues in fresh vegetables are increasingly drawing attention.Aiming at above-mentioned problems,the plasma treatment was introduced to improve the photocatalytic activity and antibacterial activity of g-C₃N₄ in this study.Subsquently,the nanofibers containing plasma-treated g-C₃N₄ with double functions of pesticide degradation and antibacterial preservation were engineered.Finally,the prepared nanofibers were applied in the preservation of fresh vegetables,and the effects of pesticide degradation and antibacterial preservation were evaluated as well.The main results are as follows:?1?The nanofibers containing plasma-treated g-C₃N₄ were filamentous,homogeneous and unreunion.Their diameter?300⁴50 nm?were significantly larger than the diameter of the nanofiber in the control group?160²40 nm?.The mechanical property,photocatalytic activity and antibacterial activity of g-C₃N₄-Plasma nanofibers were also better than the control group.?2?When the concentration of g-C₃N₄-Plasma nanofibers was 0.5%,the optimal degradation effect of organophosphorus pesticide?acephatemet pesticide,omethoate pesticide,azodrin pesticide,and dimethoate pesticide?was achieved.The degradation rate reached 70.83%⁸9.53%.The photocatalytic degradation effect of nanofibers containing plasma-treated g-C₃N₄ on organophosphorous pesticides continued to decrease with increasing initial pesticide concentration.Under visible light and sunlight,g-C₃N₄-Plasma nanofibers exhibited photocatalytic effect on four organophosphorous pesticides.?3?The g-C₃N₄-Plasma nanofibers possess a broad-spectrum bactericidal activity against several common non-pathogenic bacteria,food-borne pathogens,and drug-resistant bacteria.The sterilization rates exceeded 99.14%.The nanofibers containing plasma-treated g-C₃N₄ also had a good scavenging effect on bacterial biofilms.The clearance rates for the E.coli biofilm and the S.aureus biofilm reached99.38%and 99.61%.?4?The antibacterial mechanism of g-C₃N₄-Plasma nanofibers:The target of nanofibers containing plasma-treated g-C₃N₄ was the bacterial cell membrane,which enhanced the permeability of the cell membrane,and caused the exudation of the intracellular electrolytes and biological macromolules such as DNA,proteins,resulting in the inhibition of the normal physiological metabolism of bacteria.At the same time,the nanofibers containing plasma-treated g-C₃N₄ influenced bacterial cell respiration and metabolism by inhibiting the glycolysis?EMP?pathway.?5?The nanofibers containing plasma-treated g-C₃N₄ were applied in the preservation of four fresh vegetables?cucumber,lettuce,carrots,and tomato?.On different substrate materials,the nanofibers showed different degradation effects on acephatemet pesticides.The degradation rate of acephatemet pesticides by nanofibers loaded on kraft paper reached 49.13%⁶8.37%,and the degradation rate of acephatemet pesticides by nanofibers loaded on plastic wrap reached 72.13%⁸6.46%.The nanofibers containing plasma-treated g-C₃N₄ on different substrate materials had similar elimination effects on E.coli O157:H7 in fresh vegetables,the sterilization rate exceeded 99%.Meanwhile,they could maitain moisture,color,texture and sensory quality of fresh vegetables.