Matrix effect of montmorillonite and MCM-41 matrices on the antibacterial activity of Ag2CO3 nanoparticles

The activity and stability of nanoparticles (NPs) is known to be influenced by the nature of the supports used for their immobilization. In this study, two matrices, MCM-41 and montmorillonite (Mt) clay, were used for the incorporation of Ag2CO3 nanoparticles. MCM-41 material is a neutral matrix with high surface area, high pore volume and without the complications of a network. Mt is an ionic support with a layered structure. Non-simultaneous support decoration with antibacterial NPs by a precipitation method was used for the synthesis of bulk Ag2CO3 and nanocomposites. The two nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and ultraviolet–visible diffuse reflectance spectroscopy (DRS). The powder X-ray diffraction showed intercalation of Ag2CO3 nanoparticles into the clay interlayer space but nanoparticles have located on the surface area of mesoporous materials. The diffuse reflectance spectra indicated a strong surface plasmon resonance (SPR) absorption band in the visible region, resulting from metallic Ag nanoparticles. The two nanocomposites contained both Ag2CO3 and Ag. But the metallic silver content in MCM-41 mesoporous material was lesser in Mt clay. However, their antibacterial activities varied significantly. The antibacterial testing results demonstrated that the Ag2CO3-MCM-41 exhibited an antibacterial activity higher than that of Ag2CO3-Mt against Escherichia coli.