X-ray absorption spectroscopy has been used to study the reduction of adsorbed U(VI) during the Fe(II)-accelerated transformation of ferrihydrite to goethite. The fate of U(VI) was examined across a variety of pH values and Fe(II) concentrations, with results suggesting that, in all cases, it was reduced over the course of the Fe(III) phase transformation to a U(V) species incorporated in goethite. A positive correlation between U(VI) reduction and ferrihydrite transformation rate constants implies that U(VI) reduction was driven by the production of goethite under the conditions used in these studies. This interpretation was supported by additional experimental evidence that demonstrated the (fast) reduction of U(VI) to U(V) by Fe(II) in the presence of goethite only. Theoretical redox potential calculations clearly indicate that the reduction of U(VI) by Fe(II) in the presence of goethite is thermodynamically favorable. In contrast, reduction of U(VI) by Fe(II) in the presence of ferrihydrite is largely thermodynamically unfavorable within the range of conditions examined in this study.
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http://dx.doi.org/10.1021/es501750z | DOI Listing |
Langmuir
January 2025
Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, PR China.
This work develops Fe-Ni particles loaded on biochar (Fe-Ni/BC) to remove U(VI) efficiently. Fe-Ni bimetallic particles loaded on biochar (BC) can improve stability and reactivity, and the mesoporous structure of BC can effectively reduce Fe aggregation. The removal ability of Fe-Ni/BC is higher than that of Fe-Ni, BC, and Fe/BC.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
School of Metallurgy, Northeastern University, Shenyang, Liaoning 110819, China. Electronic address:
Applicable to convert soluble U(VI) into the less mobile U(IV) form, the photocatalytic process is widely regarded as an efficient solution to uranium pollution. In the present study, BiOI/g-CN (BICN) composites were produced through uncomplicated hydrothermal synthesis, followed by U(VI) photocatalytic reduction. Batch experiments were conducted to demonstrate the exceptional capability of BICN to address uranium contamination.
View Article and Find Full Text PDFWater Res
December 2024
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China; State Key Laboratory of Urban Water Resource and Environment, School of Civil & Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China. Electronic address:
Efficient and sustainable remediation of uranium-contaminated groundwater is critical for groundwater safety and the sustainable development of nuclear energy, particularly in the context of global carbon neutrality goals. This review explores the potential of microbial reduction processes that utilize extracellular electron transfer (EET) to convert soluble uranium (U(VI)) into its insoluble form (U(IV)), presenting a promising approach to groundwater remediation. The review first outlines the key processes and factors influencing the effectiveness of dissimilatory metal-reducing bacteria (DMRB), such as Geobacter and Shewanella, during uranium bioremediation and recovery.
View Article and Find Full Text PDFEnviron Sci Technol
December 2024
Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China.
Widespread Fe-bearing clay minerals are potential materials capable of reducing and immobilizing U(VI). However, the kinetics of this process and the impact of environmental factors remain unclear. Herein, we investigated U(VI) reduction by chemically reduced nontronite (rNAu-2) in the presence of EDTA and bicarbonate.
View Article and Find Full Text PDFEnviron Sci Technol
December 2024
CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
Uranium is the primary fuel for nuclear energy, critical for sustainable, carbon-neutral energy transitions. However, limited terrestrial resources and environmental risks from uranium contamination require innovative immobilization and recovery solutions. In this work, we present a novel uranium recovery method using programmable electroactive living materials (ELMs).
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