One-Pot Synthesis of Zinc Oxide Nanoparticle for Bromophenol Blue Adsorption and Its Antifungal Activity Against Filamentous Fungi

Abstract

Zinc oxide nanoparticles (ZnONP) have gained attention in recent years due to their multifunctional uses, potent adsorptive potential and effective antifungal activities. Despite these desirable characteristics, ZnONP has not been used for the adsorption of bromophenol blue (BRB) and tests as antifungal agents against certain important filamentous fungal strains have been limited. In this research, ZnONP was prepared via a facile one-pot synthetic approach and applied in the adsorption of BRB and as an antifungal agent against the filamentous fungi and plant pathogens; Alternaria alternata CGJM3078, Alternaria alternata CGJM3006 and Fusarium verticilliodes CGJM3823. The ZnONP was characterized by the UV, FTIR, XRD, TGA, BET, SEM, TEM, and EDX techniques, which showed efficient synthesis. The characteristics ZnO UV absorption band was observed at 375 nm, while the XRD showed an average ZnONP crystalline size of 47.2 nm. The SEM and TEM images showed an irregular shaped and aggregated porous structure of 65.3 nm average-sized ZnONPs. The Freundlich, pseudo-second-order, and intra-particle diffusion models showed R2 > 0.9494 and SSE < 0.7412, thus, exhibited the best fit to the isotherm and kinetics of adsorption. Adsorption thermodynamics revealed feasible, endothermic, random, and spontaneous adsorption of BRB onto the synthesized ZnONPs. The antifungal assay conducted, depicted strong antifungal activities against all three tested fungal cultures. A model was proposed on what causes this antifungal effect. This research demonstrated the potent use of ZnONP for the adsorption of BRB and as effective antifungal agents.