Arsenic(III) biotransformation to tooeleite associated with the oxidation of Fe(II) via Acidithiobacillus ferrooxidans. (June 2020)

• Record Type: Journal Article
• Authors: Wang, Xi; Li, Qingzhu; Liao, Qi; Yan, Yuchen; Xia, Juan; Lin, Qiuhong; Wang, Qingwei; Liang, Yanjie
• Is Part Of: Chemosphere. Volume 248(2020)
• Publication Date: 2020-06
• Subjects: Arsenic(III) -- Biosynthetic tooeleite -- Acidithiobacillus ferrooxidans -- Ferrous oxidation; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.126080
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Tooeleite (Fe6 (AsO3 )4 (SO4 )(OH)4 ·4H2 O), the only known ferric arsenite sulfate bearing mineral, has great potential for arsenic remediation due to its structure favoring incorporation of As(III). Based on the natural attenuation of removing As(III) directly by the formation of tooeleite via microorganisms, an iron-oxidizing bacterial strain Acidithiobacillus ferrooxidans ATCC 23270 ( At.ferrooxidans ) was selected to facilitate the formation of tooeleite. The optimized condition for the biogenic tooeleite was obtained at pH of 2.0, 30 °C and an initial arsenic of 500 mg/L. The process of biological mineralization is accompanied by the removal of 95.4% arsenic. What's more, biosynthetic tooeleite crystallization via a three-stage process was revealed using a combination of liquid and solid analyses (ICP-OES, XRD, XPS, FT-IR, SEM, STEM, particle distribution). The three stages included Fe 2+ oxidation by At.ferrooxidans, Fe 3+ hydrolysis and an initial Fe–As amorphous precursors formation, and finally transforming to tooeleite crystal. Moreover, RT-qPCR was used to reveal the relationship between functional gene expression of At.ferrooxidans and the mineral formation. The results showed the biogenic tooeleite exerts significant control on the geochemistry of arsenic contaminated systems. Graphical abstract: Image 1 Highlights: Fe(II) oxidation by At.ferrooxidans induced the mineralization. The role of its functional gene expression was clarified by RT-qPCR. Dissolution-recrystallization of Fe–As(III) hydroxysulfates to tooeleite proceeded. Biosynthetic tooeleite crystallization via a three-stage process was revealed.