Preparation, Characterization And Basic Research On Antibacterial Properties Of Nano-antibacterial Agents Based On Cuprous Oxide

Cu₂O nanocrystals has become a research hotspot of current antibacterial materials due to its excellent antibacterial properties,good environmental friendliness and relatively low preparation cost.However,the current research still has some limitations.On the one hand,the current optimization of the antibacterial properties of Cu₂O is mostly limited to the change of its SEM and particle size,but the antibacterial properties of Cu₂O matrix composites are rarely studied.On the other hand,there are few studies on the antibacterial mechanism of Cu₂O and its composite materials,and the antibacterial agents of Cu₂O and its composite materials need to be further studied and discussed.In view of the above problems,this paper firstly obtained Cu₂O with different morphology and particle size by different methods,and then synthesized Cu₂O matrix composites?including Cu₂O/ZnO and Cu₂O/Ag?by specific methods like X-ray Powder diffractometer?XRD?,scanning electron microscopy-energy spectroscopy?SEM-EDS?,transmission electron microscopy?TEM?physical characterization.We studied the antibacterial properties of Cu₂O,Cu₂O/ZnO and Cu₂O/Ag on Escherichia coli by inhibition zone method and growth curve method.The doping ratios of ZnO and Ag with the best antibacterial effect were found by changing the doping ratio.Then,we observed the changes of E.coli morphology in the antibacterial process by SEM,and studied the antibacterial mechanism of Cu₂O and its composites on E.coli.Finally,we apply Cu₂O and its composite materials to folic acid wastewater treatment.The specific research contents are as follows:?1?We prepared Cu₂O with cubic,oblate,deciduous and polyhedral shapes by ascorbic acid reduction,glucose reduction,honey reduction and hydrothermal methods.The antibacterial properties of these four Cu₂O were studied by the inhibition zone method.The antibacterial effect of the ascorbic acid reduction method and the honey reduction method was better.Considering the cost of preparation,we added the Cu₂O prepared by the honey reduction method to the E.coli solution to study the effect of Cu₂O on the growth curve of E.coli.It was found that the logarithmic phase of E.coli growth curve gradually became flat with the increase of Cu₂O concentration,and E.coli growth was completely inhibited when the Cu₂O concentration reached120?g/ml.After observing the change of E.coli morphology in the antibacterial process by SEM,we believe that Cu₂O mainly causes bacterial shrinkage and death by changing cell membrane permeability.We applied two different Cu₂Os to the treatment of folic acid wastewater and found that Cu₂O can inhibit the growth of bacteria in folic acid wastewater.?2?Two kinds of Cu₂O/ZnO composites with different morphology were prepared by two-step hydrothermal method and glucose reduction method.Through the inhibition zone experiment,we found that the antibacterial effect of Cu₂O/ZnO composites prepared by glucose reduction method is more obvious than that of Cu₂O.So we adjusted the input of ZnO and found the best ZnO input.Since ZnO is a good photocatalytic material,we compared the inhibition effect of Cu₂O/ZnO composites on Escherichia coli under dark conditions and simulated daylight conditions,and found that Cu₂O/ZnO composites can be used at lower concentrations under simulated sunlight conditions.Inhibits the growth of E.coli.After observing the change of E.coli morphology in the antibacterial process by SEM,we believe that the Cu₂O/ZnO composite material can achieve the antibacterial purpose mainly by destroying the bacterial cell membrane structure.We applied two different Cu₂O/ZnO composites to the treatment of folic acid wastewater.It was found that Cu₂O/ZnO composites can not only inhibit the growth of bacteria in folic acid wastewater,but also have a stronger ability to reduce COD in folic acid wastewater than Cu₂O.?3?Two kinds of Cu₂O/Ag composites were prepared by glucose reduction method and honey reduction method.By observation of morphology,we found that the Cu₂O/Ag composites obtained by honey reduction method have smaller particle size and higher dispersion.So we adjusted the doping amount of Ag and found the doping amount of Ag with the best antibacterial effect and the lowest Ag content.By studying the effect of Cu₂O/Ag composites on the growth curve of E.coli,we found that the growth of E.coli can be almost completely inhibited when the Cu₂O/Ag composite concentration reaches 10?g/mL.Observation of E.coli Morphology Changes in Antibacterial Process by SEM We believe that the process of Cu₂O/Ag composite against E.coli is to first break E.coli into short particles and then destroy the bacterial cell structure.We applied two different Cu₂O/Ag composites to the treatment of folic acid wastewater,and found that Cu₂O/Ag composites can inhibit the growth of bacteria in folic acid wastewater.