Citrate Enhanced Uranyl Adsorption on Goethite: An EXAFS Analysis

Redden, G. D.; Bargar, John R.; Bencheikh-Latmani, Rizlan

doi:10.1006/jcis.2001.7996

Cited by 59 publications

(54 citation statements)

References 18 publications

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“…In addition, there is a U-U bond distance of 3.65 Å. (5,12,48). In addition, this bond distance is similar to that found in the EXAFS spectrum of the reference sample (uranyl triacetate) measured in this work ( Fig.…”

Section: Resultssupporting

confidence: 86%

Complexation of Uranium by Cells and S-Layer Sheets of Bacillus sphaericus JG-A12

Merroun

Raff

Roßberg

et al. 2005

Appl Environ Microbiol

241

178

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Bacillus sphaericus JG-A12 is a natural isolate recovered from a uranium mining waste pile near the town of Johanngeorgenstadt in Saxony, Germany. The cells of this strain are enveloped by a highly ordered crystalline proteinaceous surface layer (S-layer) possessing an ability to bind uranium and other heavy metals. Purified and recrystallized S-layer proteins were shown to be phosphorylated by phosphoprotein-specific staining, inductive coupled plasma mass spectrometry analysis, and a colorimetric method. We used extended X-ray absorption fine-structure (EXAFS) spectroscopy to determine the structural parameters of the uranium complexes formed by purified and recrystallized S-layer sheets of B. sphaericus JG-A12. In addition, we investigated the complexation of uranium by the vegetative bacterial cells. The EXAFS analysis demonstrated that in all samples studied, the U(VI) is coordinated to carboxyl groups in a bidentate fashion with an average distance between the U atom and the C atom of 2.88 ؎ 0.02 Å and to phosphate groups in a monodentate fashion with an average distance between the U atom and the P atom of 3.62 ؎ 0.02 Å. Transmission electron microscopy showed that the uranium accumulated by the cells of this strain is located in dense deposits at the cell surface.Uranium is a long-lived radionuclide that is an ecological and human health hazard. The mining and processing of uranium for nuclear power plants and nuclear weapons production have resulted in the generation of significant amounts of radioactive wastes. The mobility of this radionuclide is controlled by its interaction with ions, minerals, and microorganisms present in nature. As a consequence of their small size and diverse metabolic activities, bacteria are able to interact intimately with metal ions present in their environment (15). Highly reactive bacterial cell surfaces bind uranium and other metal ions (7). This reactivity arises from the presence of a wide array of ionizable groups, such as carboxylate and phosphate, present in the lipopolysaccharides (LPS) of gram-negative bacterial cell walls (8) and the peptidoglycan, teichuronic acids, and teichoic acids of gram-positive bacteria (9).The bacterial cell wall may be overlayed by a number of surface structures, which can also interact with metal ions. These may be composed primarily of carbohydrate polymers (e.g., capsules) or proteinaceous surface layers (e.g., S-layers) and may occur singly or in combination (15). The crystalline bacterial cell S-layers represent the outermost cell envelope component of many bacteria and archaea (50). S-layers are generally composed of identical protein or glycoprotein subunits, and they completely cover the cell surface during all stages of bacterial growth and division. Most S-layers are 5 to 15 nm thick and possess pores of identical size and morphology in the range of 2 to 6 nm (6). As porous lattices completely covering the cell surface, the S-layers can provide prokaryotic cells with selective advantages by functioning as protective coats, as s...

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Section: Resultssupporting

confidence: 86%

Complexation of Uranium by Cells and S-Layer Sheets of Bacillus sphaericus JG-A12

Merroun

Raff

Roßberg

et al. 2005

Appl Environ Microbiol

241

178

View full text Add to dashboard Cite

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“…12). These R values are not consistent with binding of U(VI) to mineral surfaces such as goethite or clays precluding the presence of such species in significant concentrations (Redden et al, 2001;Hennig et al, 2002).…”

Section: U Binding To Dischma Soilsmentioning

confidence: 86%

Speciation of naturally-accumulated uranium in an organic-rich soil of an alpine region (Switzerland)

Regenspurg

Margot-Roquier

Harfouche

et al. 2010

Geochimica et Cosmochimica Acta

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Very high concentrations of uranium (up to 4000 ppm) were found in a natural soil in the Dischma valley, an alpine region in the Grisons canton in Switzerland. The goal of this study was to examine the redox state and the nature of uranium binding in the soil matrix in order to understand the accumulation mechanism. Pore water profiles collected from Dischma soil revealed the establishment of anoxic conditions with increasing soil depth.

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“…Factors with influence on the uranyl adsorption process to oxide minerals in presence of citric acid were determined by Logue and coworkers. Redden and coworkers have proposed formation of a ternary uranyl-citrate complexes on goethite (Redden et al, 2001). Establishing the interactions between UO2, citrate and mineral surfaces on a molecular level represents a key factor for modeling adsorption phenomena affecting transport in soils.…”

Section: Attenuated Total Reflection -Fourier Transform Infrared (Atrmentioning

confidence: 99%

Application of FTIR Spectroscopy in Environmental Studies

Simonescu¹

2012

Advanced Aspects of Spectroscopy

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Figure 1. Schematic representation of the electromagnetic spectrum (adapted from http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/Spectrpy/UV-Vis/spectrum)? Advanced Aspects of Spectroscopy 50Infrared radiation is divided into:near (NIR, ν = 10,000 -4,000 cm -1 ); -middle (MIR, ν = 4,000 -200 cm -1 ) and -far (FIR, ν = 200 -10 cm -1 ).Because all compounds show characteristic absorption/emission in the IR spectral region and based on this property they can be analyzed both quantitatively and qualitatively using FT-IR spectroscopy.Today FT-IR instruments are digitalized and are faster and more sensitive than the older ones. FT-IR spectrometers can detect over a hundred volatile organic compounds (VOC) emitted from industrial and biogenic sources. Gas concentrations in stratosphere and troposphere were determined using FT-IR spectrometers (Puckrin et al., 1996).In case of environmental studies FTIR Spectroscopy is used to analyze relevant amount of compositional and structural information concerning environmental samples (Grube et al., 2008). The analysis can be performed also to determine the nature of pollutants, but also to determine the bonding mechanism in case of pollutants removal by sorption processes. Techniques for measuring gas pollutants such as continuous air pollutants analyzer (SO2, NO2, O3, NH3), on-line gas chromatography (GC) used simple real-time instruments to quantify gas pollutants. They need to use several sensors in order to analyze multiple gas pollutants simultaneously.FT-IR spectroscopy coupled with other spectroscopic techniques such as AAS (atomic absorption spectroscopy) have been used to assess the impact of industrial and natural activities on air quality (Kumar et al., 2005;Childers et al., 2001).In addition to the traditional transmission FTIR (T-FTIR) methods (e.g. KBr-pellet or mull techniques), modern reflectance techniques are widely used today in environmental, agricultural, pharmaceuticals, and food studies. These modern techniques are attenuated total reflection FTIR (ATR-FTIR), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The choice of the method to be used depends on many factors such as: the information needed (bulk versus surface analysis), the physical form of the sample, the time required for sample preparation (Majedová et al., 2003).In the following there will be presented some of the most important research studies related to the involvement of FTIR spectroscopy in environmental studies. Traditional transmission FT-IR (T-FTIR) spectroscopy in environmental studiesTransmission spectroscopy is the oldest and most commonly used method for identifying either organic or inorganic chemicals providing specific information on molecular structure, chemical bonding and molecular environment. It can be applied to study solids, liquids or gaseous samples being a powerful tool for qualitative and quantitative studies. Application of FTIR Spectroscopy in Environmental Studies 51FTIR instrument's principle of function is the following: IR radi...

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Citrate Enhanced Uranyl Adsorption on Goethite: An EXAFS Analysis

Cited by 59 publications

References 18 publications

Complexation of Uranium by Cells and S-Layer Sheets of Bacillus sphaericus JG-A12

Complexation of Uranium by Cells and S-Layer Sheets of Bacillus sphaericus JG-A12

Speciation of naturally-accumulated uranium in an organic-rich soil of an alpine region (Switzerland)

Application of FTIR Spectroscopy in Environmental Studies

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