Please use this identifier to cite or link to this item: http://www.repositorio.ufop.br/handle/123456789/924
Title: Microwave-hydrothermal synthesis of nanostructured Na-birnessites and phase transformation by arsenic(III) oxidation.
Authors: Dias, Anderson
Sá, Rodrigo Gomes
Spitale, Matheus Calonge
Athayde, Maycon
Ciminelli, Virgínia Sampaio Teixeira
Keywords: Chemical synthesis
Raman spectroscopy
Oxides
Issue Date: 2008
Citation: DIAS, A. et al. Microwave-hydrothermal synthesis of nanostructured Na-birnessites and phase transformation by arsenic(III) oxidation. Materials Research Bulletin, v. 43, n. 6, p. 1528–1538, jun. 2008. Disponível em: <https://www.sciencedirect.com/science/article/pii/S0025540807002607>. Acesso em: 21 jun. 2012.
Abstract: Microwave-hydrothermal synthesis was employed to produce Na-birnessites. Crystalline, single-phase materials were obtained at temperatures as low as 120 8C and times as short as 1 min. X-ray diffraction and Raman spectroscopy were used to characterize the structural features of the nanostructured powders. Birnessites possessed a monoclinic structure in space group C2/m with nine Raman-active bands, all of which were observed for the first time due to optimized acquisition of the spectroscopic data. The highly reactive materials produced were submitted to sorption experiments with As(III). An oxidative precipitation occurred with the production of Mn(II) arsenate at higher arsenic concentrations. In addition, the formation of hausmannite (Mn3O4) was confirmed by X-ray diffraction and Raman analyses of the reacted solid phase. The observed 14 Raman-active modes were adjusted according to the tetragonal I41/amd space group for hausmannite. An additional band related to the breathing mode of the arsenate was observed, leading to the conclusion that adsorption onto hausmannite takes place in addition to the oxidative precipitation of manganese arsenate.
URI: http://www.repositorio.ufop.br/handle/123456789/924
ISSN: 00255408
metadata.dc.rights.license: O Periódico Materials Research Bulletin concede permissão para depósito deste artigo no Repositório Institucional da UFOP. Número da licença: 3333160000886
Appears in Collections:DEQUI - Artigos publicados em periódicos

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