Deferrization of Kaolinic Sand by Iron Oxidizing and Iron Reducing Bacteria

2007 ◽  
Vol 20-21 ◽  
pp. 130-133 ◽  
Author(s):  
Daniel Kupka ◽  
Michal Lovás ◽  
Vladimir Šepelák
Keyword(s):  
Iron Oxides ◽  
Pure Culture ◽  
Ionic Species ◽  
Raw Material ◽  
Bacterial Leaching ◽  
Iron Extraction ◽  
Iron Reducing Bacteria ◽  
Iron Oxidizing Bacteria ◽  
Reducing Bacteria ◽  
Iron Bearing

Iron oxidizing bacteria Acidithiobacillus ferrooxidans, iron reducing bacteria Acidiphilium spp. and their mixture were applied for leaching of iron impurities from quartz sand. The bacterial leaching was carried out in order to decrease the amount of colouring iron oxides and to improve the technological properties of the raw material. Mineralogical analysis confirmed the presence of siderite, iron-bearing muscovite and various amorphous and crystalline forms of iron oxides occurring both free and coating siderite and quartz particles. Mössbauer spectroscopy revealed various oxidation and magnetic states of iron ions, with the prevalence of reduced ionic species. Highest extraction of iron was achieved with pure culture of iron-reducing bacteria with ferrous iron as dominant species in the leaching liquor. Surprisingly, iron oxidizing bacteria caused passivation of the surface of iron-bearing minerals, resulting in the depression of iron leaching in comparison with abiotic control. Ferric iron was major species in the leaching solution containing the mixed culture of iron-oxidizing and iron-reducing bacteria. The mixture was far less efficient in iron extraction than pure culture of iron-reducing bacteria.

Physiochemical, mineralogical, and isotopic characterization of magnetite-rich iron oxides formed by thermophilic iron-reducing bacteria

1997 ◽  
Vol 61 (21) ◽  
pp. 4621-4632 ◽  
Author(s):  
Chuanlun Zhang ◽  
Shi Liu ◽  
Tommy J. Phelps ◽  
Dave R. Cole ◽  
Juske Horita ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Iron Reducing Bacteria ◽  
Isotopic Characterization ◽  
Reducing Bacteria

TRANSFORMATIONS IN THE Feo/Fed RATIO OF PEDOGENIC IRON OXIDES AFFECTED BY IRON-REDUCING BACTERIA

1978 ◽  
Vol 58 (4) ◽  
pp. 475-486 ◽  
Author(s):  
J. C. MUNCH ◽  
Th. HILLEBRAND ◽  
J. C. G. OTTOW
Keyword(s):  
Particle Size ◽  
Iron Oxides ◽  
Negative Correlation ◽  
Reduction Process ◽  
Flooded Soils ◽  
Iron Reducing Bacteria ◽  
Crystalline Oxides ◽  
Reducing Bacteria ◽  
Crystalline Forms ◽  
Iron Forms

In model experiments under controlled conditions of pH, particle size and amount of glucose, changes in the free Fe oxides (Fed) and acid oxalate soluble Fe (Feo) of six soils were studied after inoculation with iron-reducing, nitrogen-fixing Clostridia. In all soils, the total amount of Fed as well as crystalline Fe (Fed-Feo) decreased immediately and significantly, while Fe(II) in solution increased sigmoidally and was inversely proportional to changes in pH. Feo remained relatively constant throughout the incubation period. As a consequence, the Feo/Fed ratio increased in all samples. At the end of the reduction process, total dissolved Fe(II) correlated with the original Feo content and showed a negative correlation to Fed-Feo. These results are explained by a mechanism in which active non-crystalline iron oxides are reduced in preference to the crystalline forms. The latter are probably transformed and reduced to non-crystalline forms but not until all available active non-crystalline oxides have been exhausted. In the discussion, the reliability of acid oxalate-soluble Fe as a measure of the non-crystalline, active pedogenic iron forms is outlined. Further, the significance of a lowered redox potential (Eh or rH) in reductive transformations of flooded soils is analyzed.

Iron-mediated removal of ammonium from strong nitrogenous wastewater from food processing

2004 ◽  
Vol 49 (5-6) ◽  
pp. 421-431 ◽  
Author(s):  
V. Ivanov ◽  
J.-Y. Wang ◽  
O. Stabnikova ◽  
V. Krasinko ◽  
V. Stabnikov ◽  
...  
Keyword(s):  
Food Processing ◽  
Value Added ◽  
Microbial Reduction ◽  
Iron Hydroxides ◽  
Microbial Oxidation ◽  
Iron Reducing Bacteria ◽  
Iron Oxidizing Bacteria ◽  
Co Precipitation ◽  
Reducing Bacteria ◽  
Food Processing Wastewater

The combination of microbial reduction and further microbial oxidation of iron was applied to the treatment of food-processing wastewater and recovery of ammonium. Fe2+ ions were formed by iron-reducing bacteria under anaerobic conditions. Ammonium was recovered by co-precipitation with negatively charged iron hydroxides produced during oxidation of Fe2+ by iron-oxidizing bacteria under microaerophilic conditions. The value-added by-product of this process can be used as a slowly released ammonium fertilizer.

Reductive Dissolution of Iron Oxides and Manganese Bioleaching by Acidiphilium cryptum JF-5

2015 ◽  
Vol 1130 ◽  
pp. 347-350 ◽  
Author(s):  
Ernesto González ◽  
F. González ◽  
J.A. Muñoz ◽  
M. Luisa Blázquez ◽  
Antonio Ballester
Keyword(s):  
Iron Oxides ◽  
Reductive Dissolution ◽  
Low Grade ◽  
Manganese Ore ◽  
Iron Reducing Bacteria ◽  
Acidiphilium Cryptum ◽  
The Media ◽  
Acidic Environments ◽  
Reducing Bacteria ◽  
Positive Effect

In the development of new processes to use the potential of iron reducing bacteria,Acidiphilium cryptum, the main bacteria involved in the reduction of Fe (III) compounds in acidic environments, could play an important biohydrometallurgical role. Thus, the bioleaching of hematite, goethite and a low-grade manganese ore was assayed, in vials and columns, using three different media; two of which included a ligand, oxalate, or a redox mediator, thionine.Although the presence ofA. cryptumwas essential for promoting the dissolution of both iron oxides and the bioleaching of manganese ore, the addition of oxalate to the media tripled and quadrupled the microbial dissolution of hematite and goethite, respectively. Oxalate also had a positive effect in assays performed in columns, however, the addition of thionine to the medium allowed to reach significant hematite dissolution.

scholarly journals Inhibition of NO3− and NO2− Reduction by Microbial Fe(III) Reduction: Evidence of a Reaction between NO2− and Cell Surface-Bound Fe2+

2005 ◽  
Vol 71 (9) ◽  
pp. 5267-5274 ◽  
Author(s):  
Aaron J. Coby ◽  
Flynn W. Picardal
Keyword(s):  
Paracoccus Denitrificans ◽  
Oxide Coating ◽  
Environmental Significance ◽  
Natural Sediment ◽  
Reduction Of No ◽  
Iron Reducing Bacteria ◽  
Hypothetical Mechanism ◽  
No2 Reduction ◽  
Reducing Bacteria ◽  
Iron Bearing

ABSTRACT A recent study (D. C. Cooper, F. W. Picardal, A. Schimmelmann, and A. J. Coby, Appl. Environ. Microbiol. 69:3517-3525, 2003) has shown that NO3 − and NO2 − (NOx −) reduction by Shewanella putrefaciens 200 is inhibited in the presence of goethite. The hypothetical mechanism offered to explain this finding involved the formation of a Fe(III) (hydr)oxide coating on the cell via the surface-catalyzed, abiotic reaction between Fe2+ and NO2 −. This coating could then inhibit reduction of NOx − by physically blocking transport into the cell. Although the data in the previous study were consistent with such an explanation, the hypothesis was largely speculative. In the current work, this hypothesis was tested and its environmental significance explored through a number of experiments. The inhibition of ∼3 mM NO3 − reduction was observed during reduction of a variety of Fe(III) (hydr)oxides, including goethite, hematite, and an iron-bearing, natural sediment. Inhibition of oxygen and fumarate reduction was observed following treatment of cells with Fe2+ and NO2 −, demonstrating that utilization of other soluble electron acceptors could also be inhibited. Previous adsorption of Fe2+ onto Paracoccus denitrificans inhibited NOx − reduction, showing that Fe(II) can reduce rates of soluble electron acceptor utilization by non-iron-reducing bacteria. NO2 − was chemically reduced to N2O by goethite or cell-sorbed Fe2+, but not at appreciable rates by aqueous Fe2+. Transmission and scanning electron microscopy showed an electron-dense, Fe-enriched coating on cells treated with Fe2+ and NO2 −. The formation and effects of such coatings underscore the complexity of the biogeochemical reactions that occur in the subsurface.

Comprehensive Utilization of Pyrite with High Content of Asrenic

2012 ◽  
Vol 524-527 ◽  
pp. 965-968 ◽  
Author(s):  
Dan Liu ◽  
Shu Ming Wen ◽  
Yong Jun Xian ◽  
Hai Ying Shen ◽  
Shao Jun Bai ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Steel Industry ◽  
Raw Material ◽  
High Quality ◽  
Comprehensive Utilization ◽  
Roasting Temperature ◽  
Chinese Steel Industry ◽  
Iron Bearing

A technology of “arsenic removing- sulfuric acid producing- residuals for ironmaking” is proposed for comprehensive utilization of pyrite with high content of arsenic. The effect of roasting temperature and time on arsenic removing was investigated. The arsenic removed residuals obtained under the optimal arsenic removed conditions, was used to be proceeded for sulphur volatilization test. The results demonstrate that final residuals with 63.53% of Fe can be used for steel industry. This technology can be used to fully utilize sulphur and produce high quality concentrate as iron-bearing feed for steel industry, which will help to reduce the pollution of arsenic and extend raw material sourcing for Chinese steel industry.

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