Solubility and spectrochemical characteristics of synthetic chernikovite and meta-ankoleite

Haverbeke, L. Van; Vochten, R.; Springel, Karel van

doi:10.1180/minmag.1996.060.402.05

Cited by 40 publications

(27 citation statements)

References 12 publications

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“…6c). While the identity of the solids formed at the low TOTP condition could not be determined due to insufficient mass, particles for the high TOTP conditions resemble synthetic chernikovite [UO 2 HPO 4 Á4H 2 O (s) ] crystals (Vochten, 1990;Van Haverbeke et al, 1996). EDX analysis confirmed the presence of U and P. Sodium was not detected, which ruled out the formation of sodium meta-autunite [Na 2 (UO 2 PO 4 ) 2 ÁxH 2 O (s) ].…”

Section: Precipitation In the Absence Of Goethitementioning

confidence: 99%

Impact of phosphate on U(VI) immobilization in the presence of goethite

Singh

Ulrich

Giammar

2010

Geochimica et Cosmochimica Acta

102

101

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Section: Precipitation In the Absence Of Goethitementioning

confidence: 99%

Impact of phosphate on U(VI) immobilization in the presence of goethite

Singh

Ulrich

Giammar

2010

Geochimica et Cosmochimica Acta

102

101

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“…Solubility measurements of chernikovite and meta-ankoleite (K(UO 2 )(PO 4 )(H 2 O) 3 ), conducted by Van Haverbeke et al [61], yielded conditional K sp values from solution concentrations (not activities) of (À22.72 ± 0.24) and (À24.30 ± 0.81), respectively. Pre-experimental solid phase analysis consisted of XRD, TGA, SEM, IR, and fluorescence spectroscopy.…”

Section: Uranyl Phosphatesmentioning

confidence: 99%

Review of uranyl mineral solubility measurements

Gorman‐Lewis

Burns

Fein

2008

The Journal of Chemical Thermodynamics

215

144

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“…X-ray powder diffraction (XRD) analysis of the uranium precipitates formed by A. torulosa cells after 120 h of U exposure yielded a spectrum clearly identifiable as hydrated uranyl phosphate species, H 2 (UO 2 ) 2 (PO 4 ) 2 ·8H 2 O or chernikovite, a U(VI) autunite-type mineral (International Centre for Diffraction Data [ICDD] file 08-0296) (47,48) (Fig. 4A).…”

Section: Resultsmentioning

confidence: 99%

Unusual Versatility of the Filamentous, Diazotrophic Cyanobacterium Anabaena torulosa Revealed for Its Survival during Prolonged Uranium Exposure

Acharya

Chandwadkar

Nayak

2017

Appl Environ Microbiol

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Reports on interactions between cyanobacteria and uranyl carbonate are rare. Here, we present an interesting succession of the metabolic responses employed by a marine, filamentous, diazotrophic cyanobacterium, Anabaena torulosa for its survival following prolonged exposure to uranyl carbonate extending up to 384 h at pH 7.8 under phosphate-limited conditions. The cells sequestered uranium (U) within polyphosphates on initial exposure to 100 M uranyl carbonate for 24 to 28 h. Further incubation until 120 h resulted in (i) significant degradation of cellular polyphosphates causing extensive chlorosis and cell lysis, (ii) akinete differentiation followed by (iii) extracellular uranyl precipitation. X-ray diffraction (XRD) analysis, fluorescence spectroscopy, X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) spectroscopy established the identity of the bioprecipitated uranium as a U(VI) autunite-type mineral, which settled at the bottom of the vessel. Surprisingly, A. torulosa cells resurfaced as small green flakes typical of actively growing colonies on top of the test solutions within 192 to 240 h of U exposure. A consolidated investigation using kinetics, microscopy, and physiological and biochemical analyses suggested a role of inducible alkaline phosphatase activity of cell aggregates/akinetes in facilitating the germination of akinetes leading to substantial regeneration of A. torulosa by 384 h of uranyl incubation. The biomineralized uranium appeared to be stable following cell regeneration. Altogether, our results reveal novel insights into the survival mechanism adopted by A. torulosa to resist sustained uranium toxicity under phosphate-limited oxic conditions. IMPORTANCE Long-term effects of uranyl exposure in cyanobacteria under oxic phosphate-limited conditions have been inadequately explored. We conducted a comprehensive examination of the metabolic responses displayed by a marine cyanobacterium, Anabaena torulosa, to cope with prolonged exposure to uranyl carbonate at pH 7.8 under phosphate limitation. Our results highlight distinct adaptive mechanisms harbored by this cyanobacterium that enabled its natural regeneration following extensive cell lysis and uranium biomineralization under sustained uranium exposure. Such complex interactions between environmental microbes such as Anabaena torulosa and uranium over a broader time range advance our understanding on the impact of microbial processes on uranium biogeochemistry.KEYWORDS biomineralization, cyanobacteria, phosphatase, polyphosphates, regeneration, uranium M icroorganisms have existed on earth for at least 3.5 billion years (1) and are the most successful life forms to date (2). They have been exposed to their immediate environments comprising essential elements or complex mixtures of naturally occur-

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Solubility and spectrochemical characteristics of synthetic chernikovite and meta-ankoleite

Cited by 40 publications

References 12 publications

Impact of phosphate on U(VI) immobilization in the presence of goethite

Impact of phosphate on U(VI) immobilization in the presence of goethite

Review of uranyl mineral solubility measurements

Unusual Versatility of the Filamentous, Diazotrophic Cyanobacterium Anabaena torulosa Revealed for Its Survival during Prolonged Uranium Exposure

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