Synthesis and antimicrobial studies of nano-copper doped carbon substrates; activated carbon, reduced graphene oxide, and carbon nanofiber

Abstract

Copper oxides (CuxO) have received considerable attention as a result of their biological activity. Nanoparticles (NPs) of CuxO attached to different substrates exhibit a wide spectrum of antimicrobial activity against bacteria and viruses, with similar properties to silver. The antimicrobial activity of CuxO-NPs doped on distinctive carbon materials was investigated for three carbon substrates: apricot stone activated carbon (AAC), reduced graphene oxide (rGO) and carbon nanofiber (CNF). The CuxO-NPs (5 wt%) doped AAC and rGO substrates were prepared by impregnation of copper nitrate followed by a thermal treatment process, while a similar weight of CuxO-NPs doped CNF was fabricated by electrospinning copper nitrate with polyacrylonitrile precursor, followed by carbonization. The CuxO species and chemical functions were characterized by X-ray diffraction and Fourier transform infrared spectroscopy, respectively. Surface morphology was measured using scanning electron microscopy. The antimicrobial activities of the substrates were evaluated by inhibition zone measurement of Staphylococcus aureus and Escherichia coli. The results demonstrated significant inhibition distances for different carbon substrates. Interestingly, CuxO-NPs doped over both AAC and rGO surfaces revealed clear zones against bacteria, whereas the inhibition zone was not recorded for CuxO-NPs doped over a CNF substrate. Various parameters such as carbon substrates, particle size, and copper oxide species were investigated.