Preparation And Antibacterial Properties Of Metal-doped Magnesium Oxide By Microwave Hydrothermal Method

The design and synthesis of antibacterial materials with the characteristics of high efficiency,broad spectrum,stability,durability and low toxicity are the current research hotspots.Nano magnesium oxide,as an important inorganic chemical raw material,is not only easy to get raw materials,good biocompatibility,and can effectively inhibit bacterial growth through oxidative damage of reactive oxygen species,mechanical damage caused by adsorption,showing a broad spectrum of antibacterial activity and antibacterial performance persistence.The morphology and surface defects of nanometer magnesium oxide play an important role in its antibacterial activity,so it is still a hot topic to explore the relationship between the structure and properties of magnesium oxide so as to effectively improve the antibacterial properties of magnesium oxide.This article is guided by the regulation of antibacterial performance.Microwave hydrothermal assisted precipitation method is used to prepare nano-magnesium oxide.The structure of magnesia is regulated by means of doping and recombination to effectively improve the antibacterial effect of MgO.The main research work is as follows:?1?Preparation and antibacterial properties of lithium doped magnesium oxide.Using MgCl₂·6H₂O?NaOH?CTAB and LiNO₃ as raw materials,a series of lithium doped magnesium oxide nanosheets were prepared by microwave hydrothermal method.The structure and morphology of the product were characterized by XRD?TEM?SEM?BET and XPS.Li-doped MgO are nanosheet structure with a diameter of 50-150 nm.At the same time,the antibacterial test found that the doping of lithium significantly improved the antibacterial performance of magnesium oxide.3 mol%Li-doped MgO has the best antibacterial activity,with the minimum antibacterial concentration of 600?g/mL,and the antibacterial rate can reach more than 99%.After analysis,it is speculated that the incorporation of lithium improves the oxygen vacancy and alkalinity of magnesium oxide,reduces the band gap width,and increases the electron transfer rate,thus facilitating the formation of reactive oxygen species O^2-and hydroxyl radical·OH.At the same time,the lamellar structure,high specific surface area and pore volume of lithium doped magnesium oxide play a synergistic antibacterial effect on the mechanical damage of bacteria.?2?Study on preparation and antibacterial properties of transition metal-doped magnesium oxide.Using C₁₆H₃₆O₄Ti?MnCl₂·4H₂O?FeCl₃·6H₂O?CuCl₂·2H₂O?ZnCl₂?MgCl₂·6H₂O and AgNO₃ as raw materials,A series of transition metal doped magnesium oxide with the doping amount of 1 mol%was prepared by microwave hydrothermal method.Magnesium oxide was characterized by XRD?SEM?BET and other means.It was found that the samples were all flake,and the diameter and thickness were related to the doping elements and the doping amount.The antibacterial results showed that Ag doping MgO performed the best,completely inhibiting the growth of the two kinds of bacteria at 600?g/mL,followed by Mn and Ti-doped MgO.The antibacterial effect of pure MgO and Fe-doped MgO was basically the same,while that of Cu and Zn-doped MgO was poor.?3?Preparation and antibacterial properties of MgO-CuO-CaO metal oxide composites.MgO-CuO-CaO metal oxide composites with different proportions were synthesized by microwave hydrothermal using MgCl₂·6H₂O?CuCl₂·2H₂O?CaCl₂ as raw materials and CTAB as dispersant.The structures of the samples were characterized by XRD?SEM?BET and other characterization methods.The minimal inhibitory concentration?MIC?and colony count method were used to test the antibacterial properties of the samples.The results showed that MgO-CuO-CaO composite are nanoflake structure.MgO_0.7CuO_0.1CaO_0.2 has a specific surface area of 66.789 m²/g,an average pore diameter of 54.117 nm,and a pore volume of0.9036 cm³/g.MgO_0.7CuO_0.1CaO_0.2 showed excellent antibacterial properties at the concentration of 500?g/mL,and the antibacterial rate reached more than 99.9%at the concentration of 600?g/mL.