In this research, nanoparticles (NPs) were prepared by an easy and green method from available and cheap material (eggshell and saffron flower). The CaO@Saffron/Ag NPs were characterized using common techniques such as the furrier transform infrared (FT-IR), X-ray powder diffraction (XRD), field emission-scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), and inductively coupled plasma optical emission spectroscopy (ICP-OES). The antibacterial activity of CaO@Saffron/Ag NPs and its ability for removal of methylene blue dye from aqueous solution were investigated. CaO@Saffron/Ag NPs showed maximum inhibition zone about 10, and 8 mm against S. aureus bacteria and E. coli, respectively. Also, MIC against S. aureus bacteria and E. coli was found 4, 128 µg/mL respectively. Furthermore, an evaluation on the adsorption of methylene blue (MB) dye by CaO@Saffron/ Ag NPs revealed that the Langmuir model and the pseudo-second order are the most applicable model for adsorption isotherms and kinetics of adsorption for removing methylene blue dye from aqueous solution. Removal efficiency (R%) of MB dye obtained 98%.
