SORPTION OF FERROUS AND FERRIC IRON BY EXTRACELLULAR POLYMERIC SUBSTANCES (EPS) FROM ACIDOPHILIC BACTERIA |
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Authors: | Dr Jaime M Tapia Jesús Muñoz Felisa González Maria L Blázquez Antonio Ballester |
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Institution: | 1. Faculty of Engineering and Architecture, Section of Aqueous Process in Metallurgy, University Arturo Prat , Iquique , Chile jaime.tapia@unap.cl;3. Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica , Universidad Complutense , Madrid , Spain |
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Abstract: | The sorption of Fe(II) and Fe(III) by extracellular polymeric substances (EPS) of acidophilic bacteria Acidiphilium 3.2Sup(5) and Acidithiobacillus ferrooxidans, harvested from the ecosystem of the Tinto River (Huelva, Spain), was investigated. EPS from mixed cultures of both bacteria (EPSmixed) and pure cultures of A. 3.2Sup(5) (EPSpure) were extracted with ethylenediamine tetraacetic acid (EDTA) and were characterized by Fourier-transform infrared (FTIR), electron photoemission (XPS), x-ray diffraction (DRX), and energy dispersive x-ray (EDX) spectroscopy and scanning electron microscopy (SEM). EPS pure were loaded, in sorption tests, with Fe(II) and Fe(III). The results obtained indicate that the biochemical composition and structure of EPSmixed was very similar to that of EPSpure. Besides, results indicate that EPSmixed adsorbed Fe(II) and Fe(III) by preferential interaction with the carboxyl group, which favored the formation of Fe(II)/Fe(III) oxalates. These species were also formed in EPSpure loaded with Fe(II)/Fe(III). All this behavior suggested that the sorption of iron by EPSmixed was similar to sorption of EPSpure, which fitted the Freundlich model. Thus, the iron uptake of EPSmixed reached 516.7 ± 23.4 mg Fe/g-EPS at an initial concentration of 2.0 g/L of Fetotal and Fe(II)/Fe(III) ratio of 1.0. |
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Keywords: | acidophilic bacterium extracellular polymerical substances (EPS) ferrous and ferric oxalates iron sorption |
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