Manganese ferrite graphene nanocomposite synthesis and the investigation of its antibacterial properties for water treatment purposes

Síntese de nanocompósito de grafeno e ferrita de manganês e a investigação de suas propriedades antibacterianas para uso no tratamento de água

Abstract

The main objective of this study was to synthesize a nanocomposite using graphene and manganese ferrite nanoparticles (MnFe₂O₄-G) and to evaluate its antibacterial activity for water treatment purposes. Its morphological characteristics were evaluated by instrumental techniques, such as scanning electron microscopy and transmission electron microscopy. The characterization results indicated that the nanocomposite presented nanoparticles of approximately 25 nm well dispersed in transparent and large (14 μm) graphene nanosheets. The antibacterial activity was evaluated in a batch experiment using a concentration of 40 μg mL^-1 of nanocomposite (MnFe₂O₄-G, bare MnFe₂O₄ nanoparticles or graphene oxide), 1x10⁵ CFU mL^-1 of Escherichia coli, and 8 h of contact time at room temperature. The highest antibacterial capacity was observed for the hybrid nanocomposite (91.91%), due to the synergic effect of graphene and MnFe₂O₄ nanoparticles. Various mechanisms were proposed to explain the effective antibacterial activity of MnFe₂O₄-G, such as wrapping, oxidative stress, sharp-edge cutting effect, among others. The results showed that MnFe₂O₄-G is a potential alternative in water treatment processes as an antibacterial agent.

Keywords:
antimicrobial; magnetic; nanoparticle