Graphene Oxide/Hydroxyapatite/Silver (rGO/HAP/Ag) nanocomposite: Synthesis, characterization, catalytic and antibacterial activity

 In this paper, a novel ternary nanocomposite namely reduced graphene oxide/hydroxyapatite/silver (rGO/HAP/Ag) was prepared by a simple hydrothermal method using graphene oxide nanosheets, Ca(NO۳)۲, (NH۴)۲HPO۴, and AgNO۳ as starting materials. The as-prepared nanocomposite was characterized by using various photophysical techniques including Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), ultraviolet-visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). Additionally, the antibacterial and catalytic activities of the nanocomposite were evaluated. The results showed that the rGO/HAP/Ag nanocomposite exhibited high performance in the reduction of toxic nitro compounds (۴-nitrophenol, ۲-nitrophenol, ۴-nitroaniline, and ۲-nitroaniline) into the less toxic corresponding amines using NaBH۴ within ۲۱-۴۲ min with a rate constant equal to ۰.۱۶۴۶, ۰.۰۸۹۸, ۰.۱۰۷۱ and ۰.۲ min-۱, respectively. Moreover, the rGO/HAP/Ag nanocomposite could be separated from the reaction mixture due to its heterogeneous nature and reused without any change in structure. In addition, the antibacterial activity of the rGO/HAP/Ag nanocomposite by disk diffusion method was evaluated against Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Klebsiella pneumonia). The results showed that this novel ternary nanocomposite has good antibacterial activity against Gram-positive bacteria.

Keywords:

antibacterial activity , Graphene oxide nanosheets , hydroxyapatite , Nitro reduction , silver nanoparticles , Ternary nanocomposite