Bifunctional oxidase-peroxidase inorganic nanozyme catalytic cascade for wastewater remediation
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Universidade Federal de Minas Gerais
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Artigo de periódico
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Membros da banca
Resumo
Nanozymes are inorganic nanoparticles with enzyme-like features. Noble metals and metal oxide-based nanomaterials can present enzyme-mimicking behavior mediating catalytic reactions including oxidase-, peroxidase-,
catalase-, and superoxide dismutase-like activities with important applications in environmental and biomedical
grounds. Thus, in this study, it was designed and developed a novel nanosystem that exploits the oxidase-like
(OD) behavior of gold nanoparticles (AuNPs, GOLDzyme) and the peroxidase-like (POD) characteristics of
cobalt-doped magnetic iron oxide nanoparticles (MIONs, Co-MIONzyme) amalgamated in an inorganic-inorganic
bi-nanozyme cascade for the degradation of dye pollutants. GOLDzyme and Co-MIONzyme nanomaterials were
synthesized and stabilized by citrate and carboxymethylcellulose (CMC) ligands, respectively, using a green
aqueous colloidal process at mild conditions. The physicochemical characterization results indicated that waterdispersible colloidal supramolecular nanostructures were effectively produced, with core-shell morphologies (i.
e., inorganic nanoparticle core/organic-shell). The AuNPs (GOLDzyme) presented crystalline nanostructure, with
a uniform spherical shape, zeta potential (ZP) = - 46 ± 3 mV, hydrodynamic diameter (DH) = 11 ± 3 nm.
Analogously, the Co-MIONzyme stabilized by CMC ligand evidenced the formation of nanocrystalline substituted
magnetite (CoxFe3− xO4) with uniform spherical morphology, average size = 7.0 ± 2 nm, ZP = - 47 ± 3 mV, DH =
46 ± 3 nm, and superparamagnetic behavior. When tested separately using a colorimetric assay based on a
chromogenic molecule (3,3′,5,5′ tetramethylbenzidine, TMB), they demonstrated catalytic activity upon the
injection of each specific substrate in the medium, i.e., glucose for GOLDzyme that behaved predominantly as
oxidase-like nanomaterial, and H2O2 for Co-MIONzyme, which showed a peroxidase-like or catalase-like
behavior. In addition, these nanozymes demonstrated pH-dependent and temperature-dependent catalytic activities. As a proof of concept, when combined into a single-pot reaction system, these bifunctional nanozymes
confirmed integrated catalytic cascade as oxidase and peroxidase-like nanocatalysts towards the oxidation of
TMB and the degradation of methylene blue (MB, ~18%) as the model dye pollutant. Based on the preliminary
encouraging results of this research, it can be foreseen that the combination of nanozymes paves the way for the
development of new nanoplatforms for prospective applications in water treatment and environmental remediation.
Abstract
Assunto
Nanomateriais, Nanopartículas, Enzimas
Palavras-chave
Nanocatalyst, Nanomaterial for catalysis, Nanozyme cascade, Peroxidase-like activity, Oxidase-like activity, Bifunctional oxidase-peroxidase nanozyme
Citação
Curso
Endereço externo
https://www.sciencedirect.com/science/article/pii/S0920586121004983?via%3Dihub