Factors influencing the reduction of U(VI) by magnetite

Ma, Yue; Cheng, Xi; Kang, Mingliang; Yang, Guangze; Yin, Meiling; Wang, Jin; Song, Gang

doi:10.1016/j.chemosphere.2020.126855

Cited by 16 publications

(5 citation statements)

References 49 publications

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“…According to Figure 2B, the SI of the complex oxide of U(Ⅳ) was less than zero, except for Ca(UO2) 2 (SiO 3 OH) 2 .5H 2 O (SI > 0), indicating that under the same conditions, magnetite was poor in reducing U(Ⅵ) in this environment compared to pyrite. This was also consistent with the results of the previous study (Ma et al, 2020;Luo et al, 2022) on the reduction of U(VI) by magnetite, and only at an acidic condition, U(VI) can be successfully reduced. When considering the dissolution of calcite and quartz, the concentration of calcium and silicate ions increased from 2.236 × 10 −3 mol L −1 to 3.124 × 10 −3 mol/ L and from zero to1.843 × 10 −6 mol L −1 , respectively.…”

Section: Reduction Of U By Magnetite and Pyritesupporting

confidence: 93%

“…However, for the long-term effective isolation of radioactive wastes, pyrite and magnetite, existing widely and stably in the geological environment, have been considered to reduce the strong mobility of high-valence redox-sensitive radionuclides (U, Se, Tc, and Np) to a lowvalence state with a weak mobility state to make these lowvalence radionuclides adhere to the surrounding rock medium (Bruggeman et al, 2002;Bruggeman et al, 2005;Eglizaud et al, 2006;Naveau et al, 2007). At present, numerous previous studies (Kang et al, 2014;Ma et al, 2014;Ma et al, 2020;Hu et al, 2022a;Hu et al, 2022b;Luo et al, 2022) have been carried out on the reduction experiments of U(VI) and Se(VI) by pyrite and magnetite, and the results indicated that a high-valence state of U(VI) and Se(VI) can be successfully reduced to U(Ⅳ) and Se(0) in a low-valence state, respectively, which is easily adsorbed and migrated with difficulty. Moreover, bacteria have been widely used to reduce high-valence redox-sensitive radionuclides for bioremediation (He et al, 2021;You et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

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Prevention of radioactive pollution: A comparative simulation study on the reduction of several important radionuclides by pyrite and magnetite

Chen

Zeng

2022

Front. Environ. Sci.

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In order to ensure the long-term effective isolation of radionuclides from human beings to the environment, pyrite and magnetite, which exist widely and stably in the geological environment, can be considered to reduce the strong mobility of high-valence redox-sensitive nuclides to the low-valence nuclides with low mobility. In this work, the reducing reaction between pyrite, magnetite, and redox-sensitive radionuclides (U, Se, Tc, and Np) in the Gansu proposed-treatment plant area was under simulation by PHREEQC. Due to the considerable existence of quartz and calcite in the Gansu proposed-treatment plant area surrounding the rock of interest, the influence of the dissolved Ca2+ and SiO32- should be taken into account. The corresponding precipitation saturation index of the complex (UOX, Se(s), and TcO2) and species of interest was calculated, and the results suggested that pyrite can significantly reduce the high-valence radionuclides (U, Se, Tc, and Np), and their corresponding precipitation saturation indexes (SIs) were usually positive. However, magnetite, in a given condition, showed a certain reducing effect against Se and Np and a poor effect on U and Tc. It was worth noting that the aqueous pH in the system always remained constant because of the CO2 partial pressure of the underground biosphere under this long-term time scale. These conclusions have an important guiding significance for the prevention and retention of radioactive pollution released into the biological environment.

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Section: Reduction Of U By Magnetite and Pyritesupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Prevention of radioactive pollution: A comparative simulation study on the reduction of several important radionuclides by pyrite and magnetite

Chen

Zeng

2022

Front. Environ. Sci.

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“…Analyzing the research results on the adsorption of various (cationic and anionic) pollutants by various iron-containing adsorbents with or without magnetic properties, we can identify their particular advantage [18][19][20]. It mainly consists of the fact that such materials are able to purify water in a wide range of pH values.…”

Section: Introductionmentioning

confidence: 99%

Influence of Technological Factors on the Formation and Transformation of Iron-Containing Phases in the Process of Ferritization of Exhausted Etching Solutions

Samchenko,

Kochetov,

Trach

et al. 2024

Water

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Every year, metallurgical enterprises generate a massive amount of toxic exhausted high-concentration etching solutions. Application of the ferritization process to recycle exhausted etching solutions can help to prevent environmental pollution. It enables a cost-efficient use of water at an industrial plant and allows the plant to obtain products from toxic industrial waste and utilize it. The aim of the study was to analyze the qualitative and quantitative composition of the formed sediment and its grain size composition. Variable study parameters were the initial pH values of the solutions, the initial concentrations of total iron, and the duration of the aeration process of the reaction mixture. Thermal activation and alternating magnetic fields were used to activate the ferritization. The XRD showed that the formed sediments contained phases of γ-FeOOH, δ-FeOOH, Fe3O4, and γ-Fe2O3. Granulometry analysis showed that these sediments were highly dispersed and heterogeneous. Chemically stable phases of magnetite were obtained in the composition of sediments, with an initial concentration of iron in the reaction mixture of 16.6 g/dm3, a pH of 11.5, and a process duration of 15 min. The study results demonstrated the feasibility of further study and possible use of such sediments with a high magnetite content for the production of materials with ferromagnetic and sorption properties.

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“…In this regard, several studies investigated the interaction of heavy metal ions with magnetite surfaces. Magnetite was shown to act successfully as a reduction agent for heavy or even radioactive metals (e.g., Sb, Tc, U, − and Pu − ), often resulting in less soluble products. Hence, magnetite efficiently contributes to the immobilization of these hazardeous elements.…”

Section: Introductionmentioning

confidence: 99%

Stability and Speciation of Hydrated Magnetite {111} Surfaces from Ab Initio Simulations with Relevance for Geochemical Redox Processes

Katheras,

Karalis,

Krack

et al. 2023

Environ. Sci. Technol.

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Magnetite is a common mixed Fe(II,III) iron oxide in mineral deposits and the product of (anaerobic) iron corrosion. In various Earth systems, magnetite surfaces participate in surface-mediated redox reactions. The reactivity and redox properties of the magnetite surface depend on the surface speciation, which varies with environmental conditions. In this study, Kohn–Sham density functional theory (DFT + U method) was used to examine the stability and speciation of the prevalent magnetite crystal face {111} in a wide range of pH and E h conditions. The simulations reveal that the oxidation state and speciation of the surface depend strongly on imposed redox conditions and, in general, may differ from those of the bulk state. Corresponding predominant phase diagrams for the surface speciation and structure were calculated from first principles. Furthermore, classical molecular dynamics simulations were conducted investigating the mobility of water near the magnetite surface. The obtained knowledge of the surface structure and oxidation state of iron is essential for modeling retention of redox-sensitive nuclides.

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Factors influencing the reduction of U(VI) by magnetite

Cited by 16 publications

References 49 publications

Prevention of radioactive pollution: A comparative simulation study on the reduction of several important radionuclides by pyrite and magnetite

Prevention of radioactive pollution: A comparative simulation study on the reduction of several important radionuclides by pyrite and magnetite

Influence of Technological Factors on the Formation and Transformation of Iron-Containing Phases in the Process of Ferritization of Exhausted Etching Solutions

Stability and Speciation of Hydrated Magnetite {111} Surfaces from Ab Initio Simulations with Relevance for Geochemical Redox Processes

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