Microwave-Assisted Rapid Synthesis of Eu(OH)(3)/RGO Nanocomposites and Enhancement of Their Antibacterial Activity against Escherichia coli

Nanomaterials with high antibacterial activity and low cytotoxicity have attracted extensive attention from scientists. In this study, europium (III) hydroxide (Eu(OH)(3))/reduced graphene oxide (RGO) nanocomposites were synthesized using a rapid, one-step method, and their antibacterial activity against Escherichia coli (E. coli) was investigated using the synergistic effect of the antibacterial activity between Eu and graphene oxide (GO). The Eu(OH)(3)/RGO nanocomposites were prepared using a microwave-assisted synthesis method and characterized using X-ray diffraction, scanning electron microscopy, photoluminescence spectroscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. Raman sprectroscopy and X-ray diffraction confirmed the pure hexagonal phase structure of the nanocomposites. Further, the antibacterial properties of Eu(OH)(3)/RGO were investigated using the minimum inhibitory concentration assay, colony counting method, inhibition zone diameter, and optical density measurements. The results revealed that the Eu(OH)(3)/RGO exhibited a superior inhibition effect against E. coli and a larger inhibition zone diameter compared to RGO and Eu(OH)(3). Further, the reusability test revealed that Eu(OH)(3)/RGO nanocomposite retained above 98% of its bacterial inhibition effect after seven consecutive applications. The high antibacterial activity of the Eu(OH)(3)/RGO nanocomposite could be attributed to the release of Eu(3+) ions from the nanocomposite and the sharp edge of RGO. These results indicated the potential bactericidal applications of the Eu(OH)(3)/RGO nanocomposite.