Assessment of released natural radionuclides by waste rock pile and mining pit associated with a uranium mine at Caldas, Minas Gerais, Brazil

Pereira, Wagner de Souza; Kelecom, Alphonse; Charles-Pierre, Maxime; Lopes, José Marques; Campelo, Emanuele Lazzaretti Cordova; Espindola, Cleber Barreto; Carmo, Alessander Sá do; Py, Delcy A.; Pelegrineli, Samuel Queiroz; Silva, Ademir X.

doi:10.1007/s11356-022-19887-4

“…[3] In-situ remediation has become hotspot of current researches. [4] Among various remediation strategies, the immobilization of U(VI) via U-P precipitation has been considered a promising approach, due to phosphate combined with uranium has been investigated to form stable U-P precipitates or corresponding minerals. [5,6] Phosphate as a uranium stabilizer offers considerable potential for environmental cleanup.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Bacteria on Uranium Sequestration Stability by Different Forms of Phosphorus

Tan,

Deng,

Cun

et al. 2024

Preprint

1

0

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Immobilization of uranium (VI) via uranium-phosphate (U-P) precipitation exhibits a great potential in remediation of uranium in contaminated environments. However, phosphorus as a vital element of bacteria, the decomposition, absorption and transformation of phosphorus may affect the stability of uranium with aging time. The main purpose of this work is to study the effect of bacteria on uranium sequestration mechanism and stability by different forms of phosphorus in a water sedimentary system. The results showed that addition of phosphate effectively enhanced uranium removal rate, with the highest removal rate of 99.84%. According to the X-Ray Diffraction (XRD), Scanning Electron Microscopy and Energy Dispersive Spectrometer (SEM-EDS) analyses, the fugitive positions of phosphorus and uranium elements remained essentially the same on the sediment surface, meanwhile the appearance of more pronounced phosphorus and uranium signal peaks confirmed the existence of U-P precipitates. X-ray Photoelectron Spectroscopy (XPS) analyses imply that hexavalent uranium and tetravalent uranium co-exist in the precipitate. Combined with BCR results, bacteria and phosphorushave a synergistic effect on uranium immobilization, although there will be a small part of uranium release due to the action of bacteria with the extension of time. Collectively, the results demonstrated that bacteria and phosphorus could effectively mediate U-P precipitates, realizing the transformation and immobilization of uranium from a transferable phase to a stable phase. The experimental findings could provide theoretical evidence for uranium immobilization in uranium-contaminated groundwater sediment.

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“…[3] In-situ remediation has become hotspot of current researches. [4] Among various remediation strategies, the immobilization of U(VI) via U-P precipitation has been considered a promising approach, due to phosphate combined with uranium has been investigated to form stable U-P precipitates or corresponding minerals. [5,6] Phosphate as a uranium stabilizer offers considerable potential for environmental cleanup.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Bacteria on Uranium Sequestration Stability by Different Forms of Phosphorus

Tan,

Deng,

Lv

et al. 2024

Preprint

0

View full text Add to dashboard Cite

Immobilization of uranium (VI) via uranium-phosphate (U-P) precipitation exhibits a great potential in remediation of uranium in contaminated environments. However, phosphorus as a vital element of bacteria, the decomposition, absorption and transformation of phosphorus may affect the stability of uranium with aging time. The main purpose of this work is to study the effect of bacteria on uranium sequestration mechanism and stability by different forms of phosphorus in a water sedimentary system. The results showed that addition of phosphate effectively enhanced uranium removal rate, with the highest removal rate of 99.84%. According to the X-Ray Diffraction (XRD), Scanning Electron Microscopy and Energy Dispersive Spectrometer (SEM-EDS) analyses, the fugitive positions of phosphorus and uranium elements remained essentially the same on the sediment surface, meanwhile the appearance of more pronounced phosphorus and uranium signal peaks confirmed the existence of U-P precipitates. X-ray Photoelectron Spectroscopy (XPS) analyses imply that hexavalent uranium and tetravalent uranium co-exist in the precipitate. Combined with BCR results, bacteria and phosphorushave a synergistic effect on uranium immobilization, although there will be a small part of uranium release due to the action of bacteria with the extension of time. Collectively, the results demonstrated that bacteria and phosphorus could effectively mediate U-P precipitates, realizing the transformation and immobilization of uranium from a transferable phase to a stable phase. The experimental findings could provide theoretical evidence for uranium immobilization in uranium-contaminated groundwater sediment.

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“…Uranium pollutants downstream migration from uranium tailings are increasing without interruption (Knox et al 2008, Xie et al 2019). Presently, it has aroused a widespread concern of numerous countries on uranium contaminated water or soil (Cheng et al 2022, Pereira et al 2022).…”

Section: Introductionmentioning

confidence: 99%

Bacteria Mediated Uranium Species Transformation and Immobilization Mechanism in a Phosphate-rich System

Cun

¹

,

Tan

²

,

Peng

³

et al. 2022

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0

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Uranium tailings without reliable anti-seepage treatment in the early years of mining and metallurgy has become a potential source of pollution. This work sought to explore the transformation and mechanism of uranium species in a bacteria and phosphate coexist system. The results showed that addition of phosphate enhanced uranium removal rate greatly in solution with the highest removal rate of 99.84%. Likewise, BCR finding displayed that residual phase in sediment samples of phytic acid group and nano-hydroxyapatite group was much higher than that of control group. XRD/SEM-EDS analyses revealed that the fugitive positions of phosphorus and uranium elements remain essentially the same on the sediment surface in the groundwater-sediment system, the appearance of more pronounced phosphorus and uranium signal peaks confirmed more U-P precipitates. Combined with XPS and BCR results, very interesting, phosphate could be complexed with hexavalent uranium to form a stable precipitate. This, to some extent, do not seem to support the view that tetravalent uranium is only stable state under reducing conditions. From this point of view, it demonstrates that bacteria can effectively mediated U-P precipitates. This also provides theoretical evidence that it succeeds efficiently in realizing the transformation of uranium from a transferable phase to a stable phase, which has a potential application value to groundwater in uranium mining areas.

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Assessment of released natural radionuclides by waste rock pile and mining pit associated with a uranium mine at Caldas, Minas Gerais, Brazil

Cited by 14 publications

References 37 publications

The Effect of Bacteria on Uranium Sequestration Stability by Different Forms of Phosphorus

The Effect of Bacteria on Uranium Sequestration Stability by Different Forms of Phosphorus

The Effect of Bacteria on Uranium Sequestration Stability by Different Forms of Phosphorus

Bacteria Mediated Uranium Species Transformation and Immobilization Mechanism in a Phosphate-rich System

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