Synthesis and Characterization of Zno/Bentonite, ??-Fe2O3/Bentonite, and Zno/??-Fe2O3/Bentonite Nanocomposites for Antibacterial and Antifungal Applications

Abstract

Infectious diseases caused by bacteria and fungi pose significant global health challenges, and the emergence of drug-resistant bacterial strains has become a serious threat human health. To address this issue, the present study aimed to ZnO/Bentonite, α-Fe2O3/Bentonite, and ZnO/α-Fe2O3/Bentonite nanocomposites using Hagenia abyssinica green method as antifungal and antibacterial agents. The study compared the antibacterial and antifungal efficacy of various ratios of synthesized Nanoparticles (NPs) and Nanocomposites (NCs) through green route. The synthesized materials were characterized using various techniques, including TGA, XRD, SEM, TEM, XPS, UV-DRS, FTIR, and CEC. XRD analysis confirmed the formation of α-Fe2O3 (spinel structure) and ZnO hexagonal phase (wurtzite structure) with different ratios. The XRD patterns of the primary, binary, and ternary nanocomposites confirmed the formation of (1:2), (1:1) α-Fe2O3 NPs and (1:2), (1:1), and (2:1) ZnO NPs,(1:1),(1:2) and (2:1) α-Fe2O3 /Bentonite, (1:1),(1:2) and (2:1) ZnO/Bentonite, and (1:1:1),(1:1:3) and (2:2:1) ZnO /α-Fe2O3/Bentonite NCs. The average crystalline sizes of these NPs and NCs were estimated to be about 10.36-30.1 nm, depending on the composition. UV-Vis DRS confirmed the band gap energy of synthesized NPs and NCs, ranging from 2.00-3.87 eV. The study found that the (1:1:1) ZnO /α-Fe2O3 /Bentonite NCs exhibited the best antibacterial activity towards E. coli and S. aureus, with maximum values of 13 ± 0.3, 16 ± 0.3 at a dosage of 10 mg/mL, compared to the positive control. The (1:1:1) α-Fe2O3/ZnO/Bentonite ratio also displayed the best antifungal activity against Candida albicans, with a maximum zone of inhibition of 13 mm at a concentration of 10 mg/mL. The observed Minimum inhibitor concentration (MIC), minimum bacterial concentration (MBC), and minimum fungal concentration (MFC) values for α-Fe2O3/ZnO/Bentonite NCs were 156.25 µg/mL, 78.125µg/mL, and 39.06 µg/mL respectively, for E. coli, S. aureus, and Candida albicans. The MBC and MFC results above 0.078 mg/mL showed no bacterial or fungal colony growth, indicating the potential of α-Fe2O3/ZnO/Bentonite as an effective antibacterial and antifungal agent.