Plant-mediated synthesis of dual-functional Eggshell/Ag nanocomposites towards catalysis and antibacterial applications

Advances in nanotechnology provide plenty of exciting solutions to environmental issues affecting air, soil as well as water. To solve the water pollution problem caused by organics and microorganisms, development of a simple, environment-friendly, and cheap method for the synthesis of nanomaterials is of paramount importance. Herein, we prepared a novel nanocomposite (named Eggshell/Ag) using waste eggshell as a support and Cacumen platycladi extract as reducing and stabilizing agents in aqueous solutions at room temperature. Biogenic-stabilized Ag nanoparticles (Ag NPs) with an average diameter of 60 nm were well-dispersed on the surface of eggshells, exhibiting dual-functional properties of organics catalytic degradation and bacterial growth inhibition. Through five repeated assays, it was established that the reduction efficiency of the nanocomposite for 4-nitrophenol (4-NP) was high. The reduction could be completed rapidly at room temperature. Moreover, significant inhibition zones were observed for Staphylococcus aureus (S. aureus) agar plates and Escherichia coli (E. coli). Meanwhile, the minimum inhibition concentrations (MIC) were determined to be 0.08 and 0.04 mg mL(-1), respectively, while the minimum bactericidal concentration (MBC) was measured as 0.64 mg mL(-1). The biogenic Eggshell/Ag nanocomposites are promising candidates for a series of applications in the fields of biomedicine, environment as well as energy.