Magnesium oxide nanoparticles are a new type of inorganic material that has been widely studied and applied due to its excellent optical, electrical, magnetic, and mechanical properties. At present, it has also shown significant advantages in the field of antibacterial. Based on the unique antibacterial mechanism and antimicrobial properties of magnesium oxide nanoparticles, the doping and composite modification of magnesium oxide nanoparticles were carried out to further improve its antibacterial activity and broaden its application field.
The effects of ion doping on the structure, morphology and antimicrobial properties of magnesium oxide nanoparticles were investigated by selecting titanium ions (Ti4+), zinc ions (Zn2+) and lithium ions (Li+) for the doping experiments. Meanwhile, the Ag/MgO composites were prepared by in situ composite technology, and the effects of solvent and magnesium oxide particle size on the preparation of Ag/MgO composites were investigated, and the in situ composite mechanism and antibacterial properties were initially discussed.
Magnesium nitrate, lithium nitrate, zinc nitrate hexahydrate and n-butyl titanate were used as raw materials, and citric acid was used as complexing agent to prepare different metal ion-doped magnesium oxide nano powders by sol-gel method.
The XRD results showed that the precursors were all amorphous and magnesite structure after calcination at 600 ℃, but there were differences in the intensity of diffraction peaks of different samples because different ion doping would have different effects on the crystallization of magnesium oxide; in addition, the average size of lithium-doped grains was the largest, about 23.6 nm, and it was different from the rest three, while the size of titanium-doped grains was the smallest.
The XPS results showed that lithium doping promoted oxygen vacancy generation, titanium doping inhibited it, while zinc doping had almost no effect. The minimum inhibitory concentration (MIC) and 24-h bactericidal rate were used to evaluate the antibacterial performance of the nano powders using E. coli ATCC25922 as the test strain.