Green Composite Based on Silver Nanoparticles Supported on Diatomaceous Earth: Kinetic Adsorption Models and Antibacterial Effect

A green synthesis of composite based on silver nanoparticles (AgNPs) obtained by Melissa officinalis (MO) extract and supported on diatomaceous earth (DE) was synthesized. Kinetic adsorption models were proposed to describe the sorption mechanism of AgNPs nanoparticles during the impregnation process. Theoretical models as pseudo first order, pseudo-second order, Elovich and intraparticle diffusion were developed to establish accurately the kinetic parameters, such as correlations factors (R²) and maximum Ag nanoparticles sorption capacity of the diatomite. According to the Kinetic adsorption parameters obtained, the pseudo-second order model reveals the best linear fit. Also, four types of pseudo-second order model were performed and analyzed. The proposed models describe with great precision, the adsorption mechanism of Ag nanoparticles during the impregnation process onto DE surface. Complementary, the antibacterial activity of the composite against Staphylococcus aureus and Escherichia coli were evaluated. The green composite (Ag nanoparticles/diatomaceous earth) was characterized by Electron Microscopy, X-Ray Diffraction and Infrared Spectroscopy.