| In recent years,infectious diseases caused by pathogenic bacteria have posed a serious threat to human health.In particular,since the end of 2019,the outbreak of novel Coronavirus has had a significant impact on human health,life and national economic development.With the development of antibiotics,the drug resistance of bacteria is gradually enhanced,and drug-resistant strains are also gradually emerging,which makes it imperative for us to develop new,complex and efficient antibacterial agents on the basis of existing antibacterial agents.Graphene Quantum dots(GQDs),as a derivative of graphene,have a larger specific surface area than graphene,and this excellent structural property has a better adsorption effect on bacteria,which is conducive to the capture of bacteria.Thus inhibiting the growth of bacteria graphene materials because of its special physical and chemical structure has attracted the attention of the majority of scholars.In this paper,graphene quantum dots were prepared by shock shock method,and their antibacterial properties against bacteria and Escherichia coli in air were investigated.The main contents and results are as follows:Graphene quantum dots were prepared by an innovative method called oscillation-impact method.Graphite powder was poured into the chamber of the first oscillation-impact machine under the protection of inert gas.The semi-finished product of graphene quantum dots could be obtained under the efficient movement of the chamber and impact mesons of the first oscillation-impact machine.After that,the semi-finished product and inert gas were added into the second vibrating impact machine cavity through the feeding tube to continue to shock and impact,and qualified spherical graphene quantum dots were obtained.Particle size analysis shows that the average particle size of graphene quantum dots is 4483 nm,which is slightly larger than that of traditional graphene quantum dots,and has the problem of uneven distribution.The u V-visible spectrum characterization results show that the graphene quantum dots have good absorption properties in both ultraviolet and visible phases.Scanning electron microscopy results show that graphene quantum dots have sharp edge structure.By studying the inhibitory effect of GQDs on Escherichia coli under laser irradiation,it was found that GQDs had better photothermal conversion performance,and the thermal effect gradually increased with the increase of GQDs concentration.The growth curve showed that 1.0mg/m L GQDs could completely inhibit the growth of E.coli.The survival rate of escherichia coli under laser irradiation of1.0mg/m LGQDs for 20 min and 0.6mg/m LGQDs for 25 min was 0.In the process of interaction between GQDs and Escherichia coli,GQDs can produce reactive oxygen species under the action of photodynamics,which can change the morphology of EScherichia coli and destroy the integrity of bacterial cell membrane,leading to the loss of protective barrier and metabolic disorder,thus achieving the purpose of sterilization.The sharp edge structure of GQDs can also damage the appearance of E.coli and affect its growth.The antibacterial effect of GQDs is the result of the combination of photothermal effect,photodynamic effect and its own structure.GQDs/PU sponge was prepared by loading GQDs into PU sponge,and its inhibitory effect on air microorganism was studied.It was found that GQDs/PU sponges heated by reaction kettle had better adhesion and were not easy to fall off.With the increase of GQDs adsorption amount in GQDs/PU sponge,the absorbance value of air microbial suspension gradually decreases,and the bacteria reduction rate gradually increases,that is,the number of bacteria in the air gradually decreases,and the bacteria reduction rate will also increase when the air flow rate decreases.According to the air quality evaluation standard,when the adsorption capacity of GQDs/PU sponge reaches 1200 mg and the gas flow rate is 1L/min,the air quality changes from the initial mild pollution to a relatively clean level.When the gas flow rate is 0.5L/min,the air quality changes from the initial light pollution to a clean degree.The results showed that 1200 mg GQDs/PU sponge could inhibit the growth of bacteria in the air and improve the air quality. |
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