Biosynthesis of Nanocrystal Akaganéite from FeCl2 Solution Oxidized by Acidithiobacillus ferrooxidans Cells

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• 作者：Huixin Xiong ; Yuehua Liao ; Lixiang Zhou ; Yiqun Xu ; Shimei Wang
• 刊名：Environmental Science & Technology
• 出版年：2008
• 出版时间：June 1, 2008
• 年：2008
• 卷：42
• 期：11
• 页码：4165 - 4169
• 全文大小：2913K
• 年卷期：v.42,no.11(June 1, 2008)
• ISSN：1520-5851

文摘

Akaganéite (β-FeOOH) is a major iron oxyhydroxide component in some soils, marine concretions, and acid mine drainage environments. Recently, synthetic β-FeOOH has been found to be a promising absorbent in the treatment of metal-contaminated water. It has been recognized in previous study that akaganéite could be formed via FeCl₂ chemical oxidation under specific conditions. Here we report a novel and simple method for akaganéite bioformation from FeCl₂ solution oxidized by Acidithiobacillus ferrooxidans LX5 cells at 28 °C. After acclimation in modified 9K medium containing 0.2 M chloride, Acidithiobacillus ferrooxidans cells had great potential for oxidization of Fe²⁺ as FeCl₂ solution, and then resulted in the formation of precipitates. The resulting precipitates were identified by powder X-ray diffraction and transmission FT−IR analyses to be akaganéite. Scanning electron microscopy images showed the akaganéite was spindle-shaped, approximately 200 nm long with an axial ratio of about 5, and the spindles had a rough surface. X-ray energy-dispersive spectral analyses indicated the chemical formula of the crystalloid akaganéite could be expressed as Fe₈O₈(OH)_7.1(Cl)_0.9 with Fe/Cl molar ratio of 8.93. The biogenetic akaganéite had a specific surface area of about 100 m² g⁻¹ determined by BET method.