Green synthesis of α-MnO2/Ag nanocomposite using Malva parviflora (Khabbaz) extract for antimicrobial activity

Abstract

The green synthesis method was used to make alpha manganese dioxide (α-MnO₂), silver nanoparticles (Ag NPs), and alpha-manganese dioxide/silver nanocomposite (α-MnO₂/Ag NCs) from the Malva parviflora plant leaves extract. The XRD patterns, FE-SEM analysis, AFM device, EDX spectrum, and UV–visible spectrum were used to characterize the α-MnO₂ NPs, Ag NPs, and α-MnO₂/Ag NCs. Crystal structure and crystal size values were determined through XRD patterns. The XRD results show that α-MnO₂ NPs, Ag NPs, and α-MnO₂/Ag NCs have a tetragonal and cubic shape, with crystallite sizes ranging from 13 to 25 nm, 14–38 nm, and 13–40 nm, respectively. This study also used FE-SEM to show that the α-MnO₂ NPs, Ag NPs, and α-MnO₂/Ag NCs particles are very small, measuring 38.44, 30.04, and 58.07 nm, in that order. The AFM scans showed that the α-MnO₂ NPs, Ag NPs, and α-MnO₂/Ag NCs were half-spherical and spherical, and their sizes ranged from 72.8 to 159.3 nm. The EDX spectrum and image showed α-MnO₂ NPs, Ag NPs, and α-MnO₂/Ag NCs that were pure and had Mn and Ag in them. The UV-Vis spectrum shows the energy band gaps of 5, 5.3, and 6.2 eV for α-MnO₂ NPs, Ag NPs, and α-MnO₂/Ag NCs, respectively. The diffusion method was used to look at the areas where α-MnO₂ NPs, Ag NPs, and α-MnO₂/Ag NCs stopped bacteria from growing. This study found that the inhibition zones for gram-positive bacteria (Staphylococcus aureus and staphylococcus epidemidis) were 16.00–19.00 % mm, 14.00–17.00 mm, and 15.00–17.67 mm in size. For gram-negative bacteria (Escherichia coli and Klebsiella pneumonia), they were 13.00–16.00 mm, 13.00–14.00 mm, and 14.00–20.67 mm in size. For fungi, the inhibition zone diameters (IZDs) were 4.67 ± 0.58 mm, 15.00 ± 0.00 mm, and 14.00 ± 0.58 mm, respectively. Using a green synthesis method to mix the Malva parviflora plant leaves extract with MnNO₃ and AgNO₃ salt is a pretty new idea that hasn't been seen in any study papers yet, as far as the author knows.