Nanoscale zero-valent iron supported on mesoporous silica: characterization and reactivity for Cr(VI) removal from aqueous solution.
J Hazard Mater
; 261: 295-306, 2013 Oct 15.
Article
em En
| MEDLINE
| ID: mdl-23959249
ABSTRACT
MCM-41-supported nanoscale zero-valent iron (nZVI) was sytnhesized by impregnating the mesoporous silica martix with ferric chloride, followed by chemical reduction with NaHB4. The samples were studied with a combination of characterization techniques such as powder X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) and Mössbauer spectroscopy, N2 adsorption measurements, transmission electron microscopy (TEM), magnetization measurements, and thermal analysis methods. The experimental data revealed development of nanoscale zero-valent iron particles with an elliptical shape and a maximum size of â¼80 nm, which were randomly distributed and immobilized on the mesoporous silica surface. Surface area measurements showed that the porous MCM-41 host matrix maintains its hexagonal mesoporous order structure and exhibits a considerable high surface area (609 m(2)/g). Mössbauer and magnetization measurements confirmed the presence of core-shell iron nanoparticles composed of a ferromagnetic metallic core and an oxide/hydroxide shell. The kinetic studies demonstrated a rapid removal of Cr(VI) ions from the aqueous solutions in the presence of these stabilized nZVI particles on MCM-41, and a considerably increased reduction capacity per unit mass of material in comparison to that of unsupported nZVI. The results also indicate a highly pH-dependent reduction efficiency of the material, whereas their kinetics was described by a pseudo-first order kinetic model.
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Texto completo:
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Poluentes Químicos da Água
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Cromo
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Dióxido de Silício
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Purificação da Água
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Ferro
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article