Research On Functional Fiber Packaging Materials Based On G-C₃N₄

Paper based materials have been highly used in the field of packaging because of the advantages of green and environmental protection.However,most paper-based materials do not have the property of antibacterial,thus the practical application of paper based materials are limited to a certain extent.Therefore,in this paper,taking urea and thiourea as precursor,the modified g-C₃N₄ was prepared by introducing water vapor in the process of thermal polymerization of urea and thiourea.Then the modified g-C₃N₄ was loaded on the surface of wood fiber to prepare photosensitive fiber antibacterial packaging materials.The morphology,structure,surface functional groups,photocatalytic activity and antibacterial activity of g-C₃N₄ and fiber composite packaging materials were studied in detail by SEM,FTIR,XPS and photocatalytic methylene blue（MB）experiment.The results are as follows:（1）g-C₃N₄ was prepared by water vapor modification with urea as precursor.It was found that g-C₃N₄（CN-25）has large specific surface area and porous structure when the water vapor activation time was 25 min.XPS showed that N defects was introduced into CN-25.EIS showed that CN-25 had the smallest arc radius.As could be found from the I-T curve,CN-25 displayed the highest photocurrent response.At the same time,the degradation experiment of MB suggested that CN-25 could degrade 83%MB within 180min.And the pseudo first-order reaction kinetic constant of CN-25 reached 6.04×10^-3min^-1,which was 2.11 times higher than that of unmodified g-C₃N₄.（2）Taking urea and thiourea as precursor materials,g-C₃N₄（CN-S-25）obtained when the time of wate vapor introduction was 25 min,and BET showed that the specific surface area of CN-S-25 was greatly increased.XPS indicated that when thiourea was added,S-doped g-C₃N₄ was obtained.EIS suggested that CN-S-25 presented a small arc radius,and I-T curve revealed that CN-S-25 had the highest photocurrent response.It could be seen from the degradation experiment of MB that CN-S-25 could degrade 86.4%of MB in180 min.At the same time,the pseudo first-order reaction kinetic constant of CN-S-25reached 8.85×10^-3 min^-1,which was 2.8 times that of the control group.The stability of the CN-S-25 was explored by circulation experiment.The results indicated that the catalyst still maintained good catalytic activity after three cycles.（3）Photosensitive antibacterial packaging materials were prepared by interfacial polymerization of CN-S-25 on the surface of plant fibers with m-phenylenediamine and1,3,5-trimesoyl chloride as auxiliary agents.The results showed that the interfacial polymerization of filter paper to form a dense g-C₃N₄ membrane could greatly improve the hydrophobicity of the filter paper,and the interfacial polymerization treatment could improve the thermal stability of the filter paper.The results of antibacterial experiment showed that under the condition of light,the interfacial polymerized CN-S-25 could completely eliminate E.coli in 25 minutes and Staphylococcus aureus in 30 minutes.Under dark conditions,the filter paper and CN-S-25 interfacial polymeric paper-based materials had almost no antibacterial properties.In conclusion,the above experimental results showed that the g-C₃N₄ photocatalytic antibacterial agent has good antibacterial effect and application prospects in antibacterial membrane and membrane cleaning.