The Preparation Of Antibacterial Fibrous Film Loaded G-C₃N₄ And Its Application On Preservation Of Vegetables

As a new inorganic nanomaterial,graphitic carbon nitride?g-C₃N₄?has been widely studied in the field of photocatalysis due to the advantages of cheap,high safety and non-toxic.Therefore,it possesses potential application in the field of food preservation because of its photocatalytic characteristics.However,there were few reports about the antibacterial properties of g-C₃N₄.Cold plasma is a new surface modification technology,which can be used to enhance the activity of catalyst.In this paper,cold plasma treated g-C₃N₄ was loaded on the fibrous film by electrospinning technology.Subsequently,it was ultilized in the preservation of vegetables.This study serves as a theoretical and experimental underpinning for the application of this novel food packaging.In this paper,g-C₃N₄ was prepared from urea by high temperature calcination method.Then,g-C₃N₄ was treated by cold plasma.By detecting the contents of ATP,DNA and protein in bacterial cells,the bactericidal mechanism of g-C₃N₄-Plasma against E.coli and S.aureus was evaluated.Next,the antibacterial elsctrospun fibers were obtained by lodaing g-C₃N₄-Plasma.Finally,their antibacterial activity has been verified by the application in the preservation of vegetables.?1?The g-C₃N₄ inorganic nanomaterial was prepared from urea by high temperature calcination method.Next,the surface of g-C₃N₄ was modified by cold plasma to obtain antibacterial material.The results of XRD,FT-IR,SEM,TEM,PL spectra,UV-vis spectra,particle size,Zeta potential and BET analysis showed that g-C₃N₄ has a graphite-like lamellar structure,a visible absorption band and a higher negative charge of-23.6 mV.The physicochemical properties of g-C₃N₄ have no significant changes after cold plasma treatment.?2?Under the condition of natural light,0.5%?w/v?of g-C₃N₄-Plasma exhibited high bactericidal activity against eight bacteria in food,such as Staphylococcus aureus.After 24 hours treatment,99% of bactericidal rate was reached.Under the dark conditions,g-C₃N₄-Plasma showed good antibacterial properties as well in the same treatment period.In addition,0.5% of g-C₃N₄-Plasma also had antibacterial effect on the biofilm of Escherichia coli and S.aureus.The bacteria eradication rate was 40.45% and 47.59% respectively.At the same time,g-C₃N₄ has good reusability.?3?The bactericidal mechanism of g-C₃N₄-Plasma against E.coli and S.aureus can be summarized as: g-C₃N₄-Plasma can destroy the structure of bacterial cell membrane,resulting in the increase of cell membrane permeability and the leakage of intracellular macromolecules,such as ATP,DNA and protein.As a result,bacteria can not maintain normal life activities,leading to the death of bacteria.?4?The g-C₃N₄-Plasma embedded antimicrobial film was engineered by electrospinning technology.The microscopic morphology of g-C₃N₄-Plasma nanofiber film was observed by SEM electron microscopy.g-C₃N₄ was evenly dispersed in the fiber film,and the diameter of fiber was uniform.After 24 h treatment,the sterilization rate of g-C₃N₄-Plasma nanofiber film loaded on different carriers?aluminum foil,kraft paper and plastic wrap?can reach more than 99.40%.Besides,the g-C₃N₄-Plasma loaded film exhibited long acting time.After 4 days,the sterilization rates of antibacterial films loaded on different carrier against E.coli O157:H7 on the vegetables,including cherry tomatoes,green peppers,cucumber,carrots,were about 99%.Meanwhile,the g-C₃N₄-Plasma nanofiber antibacterial film has no impact on the sensory quality of vegetables.