Nanoscale zero-valent iron supported on mesoporous silica: Characterization and reactivity for Cr(VI) removal from aqueous solution
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- 作者：Eleni Petala ; Konstantinos Dimos ; Alexios Douvalis ; Thomas Bakas ; Jiri Tucek ; Radek Zbo艡il ; Michael A. Karakassides
- 关键词：Nanoscale zero-valent iron ; Mesoporous silica ; Cr(VI) remediation ; Characterization ; Kinetics
- 刊名：Journal of Hazardous Materials
- 出版年：15 October, 2013
- 年：2013
- 卷：261
- 期：Complete
- 页码：295-306
- 全文大小：3056 K
文摘
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 M枚ssbauer 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 鈭?0 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 m2/g). M枚ssbauer 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.