Uranium sorption characteristics onto synthesized pyrite

Luo, Mingbiao; Liu, Shujuan; Li, Jianqiang; Luo, Feng; Lin, Hailu; Yao, Peipei

doi:10.1007/s10967-015-4269-0

Cited by 18 publications

(3 citation statements)

References 34 publications

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“…Using adsorption experiments, some researchers have identified uranyl monolayers on pyrite surfaces. 74,12 However, in contrast to our experiments, the presence of an electric field is not a factor in simple adsorption scenarios, although reduction still occurs. In electrochemical experiments, both the adsorption layer and the electron transfer differ from those associated with uranyl adsorption alone.…”

Section: Diffusioncontrasting

confidence: 99%

Effect of EDTA Complexation on the Kinetics and Thermodynamics of Uranium Redox Reactions Catalyzed by Pyrite: A Combined Electrochemical and Quantum-Mechanical Approach

Wang

Kim

Marcano

et al. 2022

ACS Earth Space Chem.

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Ethylenediaminetetraacetic acid (EDTA), a strong complexing agent, is a common constituent of liquid nuclear waste streams. The interaction of EDTA or other organic or inorganic ligands with uranyl enhances the mobilization of uranium and therefore significantly influences the disposal and remediation of uranium waste. Although numerous studies have focused on the effect of EDTA on the mobilization of environmental uranium, including the adsorption and redox reactions of uranium on mineral surfaces, few studies have differentiated the reaction-controlling steps (diffusion, adsorption, and chemical reaction/electron transfer) occurring at heterogeneous interfaces to assess the effect of EDTA complexation on each of these processes. Here, a combination of in situ electrochemical methods and quantum-mechanical calculations was used to study the effect of EDTA complexation on the kinetics and thermodynamics of redox reactions of uranium at the pyrite-solution interface. Experiments indicate a potential shift of U(VI)/U(V) on the pyrite surface of ∼0.04 V due to surface adsorption and −0.21 V due to EDTA complexation, with similar results from the calculations. The oxidation of the U(IV) reaction is more sensitive to EDTA complexation in solution than that of U(V). Disproportionation, affecting 2/3 of the intermediate pentavalent state, is the rate-limiting step of the overall redox cycle of uranyl. The charge transfer was controlled by diffusion and adsorption processes. EDTA can promote the delivery of free uranyl from the bulk solution to the pyrite–water interface where the reaction takes place, making the electron-transfer process less diffusion-limited. Adsorption of uranyl onto pyrite surfaces in the gradient electric field is multimolecular layer adsorption, through which electron transfer can occur.

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Section: Diffusioncontrasting

confidence: 99%

Effect of EDTA Complexation on the Kinetics and Thermodynamics of Uranium Redox Reactions Catalyzed by Pyrite: A Combined Electrochemical and Quantum-Mechanical Approach

Wang

Kim

Marcano

et al. 2022

ACS Earth Space Chem.

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Section: Xps Surface Featuresmentioning

confidence: 99%

“…Previous studies by cyclic voltammetry verified that U(VI) can be reduced to U(V) on the surface of pyrite. 47,48 However, the exact reduced U species were difficult to be identified as the binding energies for U(V) and U(IV) are very close. 49 Shoulder peaks fitted at 385.0 ± 1.0 eV were probably ascribed to the U(VI) satellite signal.…”

Section: S Concentrationmentioning

confidence: 99%

Influence of Surface Compositions on the Reactivity of Pyrite toward Aqueous U(VI)

Fernández-Martı́nez

Kang

et al. 2020

Environ. Sci. Technol.

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Pyrite plays a significant role in governing the mobility of toxic uranium in anaerobic environment via an oxidation-reduction process occurring at the mineral-water interface, but the factors influencing the reaction kinetics remain poorly known. In this study, natural pyrites with different impurities (Pb, As and Si) and different surface pretreatments were used to react with aqueous U(VI) from pH ~3.0 to ~9.5. Both aqueous and solid results indicated that freshly crushed pyrites, which do have more surface Fe 2+ /Fe 3+ and S 2sites that were generated from breaking Fe(S)-S bonds during ball-milling, exhibited a much stronger reactivity than those treated with acid-washing. Besides, U(VI) reduction which involves the possible intermediate U(V) and the formation of hyperstoichiometric UO 2+x (s) was found to preferentially occur on Pb-and As-rich spots on the pyrite surface, suggesting that the impurity doping could act as reactive sites due to the generation of lattice defects and galena-and arsenopyritelike local configurations. These reactive surface sites can be removed by acid-washing, leaving a pyrite surface nearly inert towards aqueous U(VI). Thus, reactivity of pyrite towards U(VI) is largely governed by its surface compositions, which provides an insight on the chemical behavior of both pyrite and uranium in various environments.

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Applicability of polyvinylpolypyrrolidone adsorbent to treatment process of wastes containing uranium

Ohashi

Harada

Asanuma

et al. 2016

J Radioanal Nucl Chem

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Uranium sorption characteristics onto synthesized pyrite

Cited by 18 publications

References 34 publications

Effect of EDTA Complexation on the Kinetics and Thermodynamics of Uranium Redox Reactions Catalyzed by Pyrite: A Combined Electrochemical and Quantum-Mechanical Approach

Effect of EDTA Complexation on the Kinetics and Thermodynamics of Uranium Redox Reactions Catalyzed by Pyrite: A Combined Electrochemical and Quantum-Mechanical Approach

Influence of Surface Compositions on the Reactivity of Pyrite toward Aqueous U(VI)

Applicability of polyvinylpolypyrrolidone adsorbent to treatment process of wastes containing uranium

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