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Hu Y, Xue Q, Chen H, Guo H, Carroll KC, Wang S. Mechanistic insight into Cr(VI) retention by Si-containing ferrihydrite. J Environ Sci (China) 2024; 139:217-225. [PMID: 38105049 DOI: 10.1016/j.jes.2023.05.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/21/2023] [Accepted: 05/28/2023] [Indexed: 12/19/2023]
Abstract
Hexavalent chromium [Cr(VI)] causes serious harm to the environment due to its high toxicity, solubility, and mobility. Ferrihydrites (Fh) are the main adsorbent and trapping agent of Cr(VI) in soils and aquifers, and they usually coexist with silicate (Si), forming Si-containing ferrihydrite (Si-Fh) mixtures. However, the mechanism of Cr(VI) retention by Si-Fh mixtures is poorly understood. In this study, the behaviors and mechanisms of Cr(VI) adsorption onto Si-Fh with different Si/Fe molar ratios was investigated. Transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and other techniques were used to characterize Si-Fh and Cr(VI)-loading of Si-Fh. The results show that specific surface area of Si-Fh increases gradually with increasing Si/Fe ratios, but Cr(VI) adsorption on Si-Fh decreases with increasing Si/Fe ratios. This is because with an increase in Si/Fe molar ratio, the point of zero charge of Si-Fh gradually decreases and electrostatic repulsion between Si-Fh and Cr(VI) increases. However, the complexation of Cr(VI) is enhanced due to the increase in adsorbed hydroxyl (A-OH-) on Si-Fh with increasing Si/Fe molar ratio, which partly counteracts the effect of the electrostatic repulsion. Overall, the increase in the electrostatic repulsion has a greater impact on adsorption than the additional complexation with Si-Fh. Density functional theory calculation further supports this observation, showing the increases in electron variation of bonding atoms and reaction energies of inner spherical complexes with the increase in Si/Fe ratio.
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Affiliation(s)
- Ying Hu
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China; Beijing Key Laboratory of Water Resources and Environmental Engineering, School of Water Resources and Environment, China University of Geosciences, Beijing 100083, China
| | - Qiang Xue
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China; Beijing Key Laboratory of Water Resources and Environmental Engineering, School of Water Resources and Environment, China University of Geosciences, Beijing 100083, China.
| | - Honghan Chen
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China; Beijing Key Laboratory of Water Resources and Environmental Engineering, School of Water Resources and Environment, China University of Geosciences, Beijing 100083, China
| | - Huaming Guo
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China.
| | - Kenneth C Carroll
- Plant & Environmental Science, New Mexico State University, NM 88003, USA
| | - Song Wang
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, China
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2
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Li Y, Hou J, Miao L, Wu J, Xing B. Influence of humate on the degradation of chloramphenicol by sulfidated ferrihydrite under dynamic anoxic/oxic environments: A combined DFT calculation and experimental study. WATER RESEARCH 2023; 244:120471. [PMID: 37597445 DOI: 10.1016/j.watres.2023.120471] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 08/06/2023] [Accepted: 08/08/2023] [Indexed: 08/21/2023]
Abstract
Sulfidation of ferrihydrite is known to affect the degradation of contaminants, but little was known about the role of natural organic matter (NOM) in antibiotics degradation by sufidated ferrihydrite under redox-dynamic conditions. Here, a typical antibiotic (i.e., chloramphenicol (CAP)) was chosen to investigate how it redistributed when ferrihydrite reacted with reductive dissolved sulfide (S(-II)dis) in the presence of humate (HA) under dynamic anoxic/oxic environments. In anoxic environments, HA enhanced CAP reduction via dichlorination or decarboxylation by sufidated ferrihydrite in the low concentration of S(-II), while HA inhibited CAP reduction in the high concentration of S(-II) by the contribution of S(-II) and surface-bound Fe(II) (Fe(II)adsorbed). When the conditions transited from anoxic to oxic, remaining CAP molecules in solutions continued undergoing oxidative degradation to form the succinic acid, hexanedioic acid, CO2, and H2O by the attack of ·OH. Meantime, HA was adsorbed to ferrihydrite to block autocatalytic Fe(II) oxidation, which inhibited the generation of ·OH under oxic conditions. Additionally, from the density function theory (DFT) calculation and intermediate products analysis obtained from HPLC-MS/MS, two oxidative degradation pathways of CAP during the oxidation of sulfidated ferrihydrite have been proposed. Collectively, the framework elucidated different roles of HA in CAP elimination and environmental behavior of ferrihydrite when exposed to the S(-II) under the dynamic redox conditions.
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Affiliation(s)
- Yan Li
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Jun Hou
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Lingzhan Miao
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Jun Wu
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, United States of America
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3
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Notini L, Schulz K, Kubeneck LJ, Grigg ARC, Rothwell KA, Fantappiè G, ThomasArrigo LK, Kretzschmar R. A New Approach for Investigating Iron Mineral Transformations in Soils and Sediments Using 57Fe-Labeled Minerals and 57Fe Mössbauer Spectroscopy. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023. [PMID: 37364169 DOI: 10.1021/acs.est.3c00434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
Iron minerals in soils and sediments play important roles in many biogeochemical processes and therefore influence the cycling of major and trace elements and the fate of pollutants in the environment. However, the kinetics and pathways of Fe mineral recrystallization and transformation processes under environmentally relevant conditions are still elusive. Here, we present a novel approach enabling us to follow the transformations of Fe minerals added to soils or sediments in close spatial association with complex solid matrices including other minerals, organic matter, and microorganisms. Minerals enriched with the stable isotope 57Fe are mixed with soil or sediment, and changes in Fe speciation are subsequently studied by 57Fe Mössbauer spectroscopy, which exclusively detects 57Fe. In this study, 57Fe-labeled ferrihydrite was synthesized, mixed with four soils differing in chemical and physical properties, and incubated for 12+ weeks under anoxic conditions. Our results reveal that the formation of crystalline Fe(III)(oxyhydr)oxides such as lepidocrocite and goethite was strongly suppressed, and instead formation of a green rust-like phase was observed in all soils. These results contrast those from Fe(II)-catalyzed ferrihydrite transformation experiments, where formation of lepidocrocite, goethite, and/or magnetite often occurs. The presented approach allows control over the composition and crystallinity of the initial Fe mineral, and it can be easily adapted to other experimental setups or Fe minerals. It thus offers great potential for future investigations of Fe mineral transformations in situ under environmentally relevant conditions, in both the laboratory and the field.
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Affiliation(s)
- Luiza Notini
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, CHN, Universitätstrasse 16, Zurich CH-8092, Switzerland
| | - Katrin Schulz
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, CHN, Universitätstrasse 16, Zurich CH-8092, Switzerland
| | - L Joëlle Kubeneck
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, CHN, Universitätstrasse 16, Zurich CH-8092, Switzerland
| | - Andrew R C Grigg
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, CHN, Universitätstrasse 16, Zurich CH-8092, Switzerland
| | - Katherine A Rothwell
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, CHN, Universitätstrasse 16, Zurich CH-8092, Switzerland
| | - Giulia Fantappiè
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, CHN, Universitätstrasse 16, Zurich CH-8092, Switzerland
| | - Laurel K ThomasArrigo
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, CHN, Universitätstrasse 16, Zurich CH-8092, Switzerland
| | - Ruben Kretzschmar
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, CHN, Universitätstrasse 16, Zurich CH-8092, Switzerland
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4
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Xu J, Yang H, Hou J, Miao L, Wu J. Role of humic acid in the transformation of hexavalent chromium in a sulfidated ferrihydrite system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 863:160884. [PMID: 36528100 DOI: 10.1016/j.scitotenv.2022.160884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 12/07/2022] [Accepted: 12/08/2022] [Indexed: 06/17/2023]
Abstract
Ferrihydrite (Fh) often coexists with organic matter (i.e., humic acid (HA)) in the environment; however, its impacts on the transformation of hexavalent chromium (Cr(VI)) is poorly understood during the sulfidation of Fh. Upon exposed to 2 mM sulfide for 12 h, the total amount of Fe(II) (Fe(II)tot, 0.78 mM) in treatments with HA (300 mg HA/L) was higher than that (0.67 mM) in treatments without HA, since HA could enhance the solubility of Fe(II). After then, the Cr(VI) was reduced by sulfidated Fh. Aqueous Cr(VI) concentration (Cr(VI)aq) declined from 0.67 to 0.43 mM with the increase of HA concentration from 0 to 400 mg/L, which was partly ascribed to the inhibition of surface passivation by HA. Moreover, the increase in Fe(II) during the sulfidation of Fh also exerted a strong impact on the transformation of Cr(VI) subsequently. In addition of HA, batch experiments suggested that EDTA could also promote the formation of Fe(II) (Fe(II)tot, 0.80 mM), rendering a lower Cr(VI)aq (0.59 mM) in EDTA-300 treatments. This study further demonstrated that HA played an important role in the transformation of Cr(VI), hence providing a theoretical basis for in-situ remediation of Cr(VI) in the future.
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Affiliation(s)
- Jiayi Xu
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, People's Republic of China
| | - Hanpei Yang
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, People's Republic of China
| | - Jun Hou
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, People's Republic of China
| | - Lingzhan Miao
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, People's Republic of China
| | - Jun Wu
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
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5
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Nie M, Li X, Ding Y, Pan Y, Cai Y, Liu Y, Liu J. Effect of Stoichiometry on Nanomagnetite Sulfidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:3002-3011. [PMID: 36745694 DOI: 10.1021/acs.est.2c08179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Magnetite (Mt) has long been regarded as a stable phase with a low reactivity toward dissolved sulfide, but natural Mt with varying stoichiometries (the structural Fe(II)/Fe(III) ratio, xstru) might exhibit distinct reactivities in sulfidation. How Mt stoichiometry affects its sulfidation processes and products remains unknown. Here, we demonstrate that xstru is a master variable controlling the rates and extents of sulfide oxidation by magnetite nanoparticles (11 ± 2 nm). At pH = 7.0-8.0 and the initial Fe/S molar ratio of 10-50, the partially oxidized magnetite (xstru = 0.19-0.43) can oxidize dissolved sulfide to elemental sulfur (S0), but only surface adsorption of sulfide, without interfacial electron transfer (IET), occurs on the nearly stoichiometric magnetite (xstru = 0.47). The higher initial rate and extent of sulfide oxidation and S0 production are observed with the more oxidized magnetite that has the higher electron-accepting capability from surface-complexed sulfide (S(-II)(s)). The FeS clusters formed from magnetite sulfidation can be oxidized by the most oxidized magnetite with xstru = 0.19 but not by other magnetite particles. A linear relationship between the Gibbs free energy of reaction and the surface area-normalized initial rate of sulfide oxidation is observed in all experiments under the different conditions, suggesting the S(-II)(s)-magnetite IET dominates magnetite sulfidation at high Fe/S molar ratios and near-neutral pH.
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Affiliation(s)
- Mingjun Nie
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing100871, China
| | - Xiaoxu Li
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing100871, China
| | - Yuefei Ding
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing100871, China
| | - Yuguan Pan
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing210023, China
| | - Yuanfeng Cai
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing210023, China
| | - Yuanyuan Liu
- Key Laboratory of Surficial Geochemistry (Ministry of Education), School of Earth Sciences and Engineering, Nanjing University, Nanjing210023, China
| | - Juan Liu
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing100871, China
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6
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Stagg O, Morris K, Townsend LT, Kvashnina KO, Baker ML, Dempsey RL, Abrahamsen-Mills L, Shaw S. Sulfidation and Reoxidation of U(VI)-Incorporated Goethite: Implications for U Retention during Sub-Surface Redox Cycling. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17643-17652. [PMID: 36449568 PMCID: PMC9775214 DOI: 10.1021/acs.est.2c05314] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 11/06/2022] [Accepted: 11/08/2022] [Indexed: 06/17/2023]
Abstract
Over 60 years of nuclear activity have resulted in a global legacy of contaminated land and radioactive waste. Uranium (U) is a significant component of this legacy and is present in radioactive wastes and at many contaminated sites. U-incorporated iron (oxyhydr)oxides may provide a long-term barrier to U migration in the environment. However, reductive dissolution of iron (oxyhydr)oxides can occur on reaction with aqueous sulfide (sulfidation), a common environmental species, due to the microbial reduction of sulfate. In this work, U(VI)-goethite was initially reacted with aqueous sulfide, followed by a reoxidation reaction, to further understand the long-term fate of U species under fluctuating environmental conditions. Over the first day of sulfidation, a transient release of aqueous U was observed, likely due to intermediate uranyl(VI)-persulfide species. Despite this, overall U was retained in the solid phase, with the formation of nanocrystalline U(IV)O2 in the sulfidized system along with a persistent U(V) component. On reoxidation, U was associated with an iron (oxyhydr)oxide phase either as an adsorbed uranyl (approximately 65%) or an incorporated U (35%) species. These findings support the overarching concept of iron (oxyhydr)oxides acting as a barrier to U migration in the environment, even under fluctuating redox conditions.
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Affiliation(s)
- Olwen Stagg
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, ManchesterM13 9PL, U.K.
| | - Katherine Morris
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, ManchesterM13 9PL, U.K.
| | - Luke Thomas Townsend
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, ManchesterM13 9PL, U.K.
| | - Kristina O. Kvashnina
- The
Rossendorf Beamline at ESRF—The European Synchrotron, CS40220, Grenoble Cedex 938043France
- Institute
of Resource Ecology, Helmholtz Zentrum Dresden
Rossendorf (HZDR), Dresden01314, Germany
| | - Michael L. Baker
- Department
of Chemistry, The University of Manchester, ManchesterM13 9PL, U.K.
- The
University of Manchester at Harwell, The University of Manchester, Diamond Light Source, Harwell Campus, DidcotOX11 0DE, U.K.
| | - Ryan L. Dempsey
- Department
of Chemistry, The University of Manchester, ManchesterM13 9PL, U.K.
| | | | - Samuel Shaw
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, ManchesterM13 9PL, U.K.
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7
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Xiu W, Wu M, Nixon SL, Lloyd JR, Bassil NM, Gai R, Zhang T, Su Z, Guo H. Genome-Resolved Metagenomic Analysis of Groundwater: Insights into Arsenic Mobilization in Biogeochemical Interaction Networks. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10105-10119. [PMID: 35763428 DOI: 10.1021/acs.est.2c02623] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
High-arsenic (As) groundwaters, a worldwide issue, are critically controlled by multiple interconnected biogeochemical processes. However, there is limited information on the complex biogeochemical interaction networks that cause groundwater As enrichment in aquifer systems. The western Hetao basin was selected as a study area to address this knowledge gap, offering an aquifer system where groundwater flows from an oxidizing proximal fan (low dissolved As) to a reducing flat plain (high dissolved As). The key microbial interaction networks underpinning the biogeochemical pathways responsible for As mobilization along the groundwater flow path were characterized by genome-resolved metagenomic analysis. Genes associated with microbial Fe(II) oxidation and dissimilatory nitrate reduction were noted in the proximal fan, suggesting the importance of nitrate-dependent Fe(II) oxidation in immobilizing As. However, genes catalyzing microbial Fe(III) reduction (omcS) and As(V) detoxification (arsC) were highlighted in groundwater samples downgradient flow path, inferring that reductive dissolution of As-bearing Fe(III) (oxyhydr)oxides mobilized As(V), followed by enzymatic reduction to As(III). Genes associated with ammonium oxidation (hzsABC and hdh) were also positively correlated with Fe(III) reduction (omcS), suggesting a role for the Feammox process in driving As mobilization. The current study illustrates how genomic sequencing tools can help dissect complex biogeochemical systems, and strengthen biogeochemical models that capture key aspects of groundwater As enrichment.
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Affiliation(s)
- Wei Xiu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, P. R. China
- Institute of Earth sciences, China University of Geosciences (Beijing), Beijing 100083, P. R. China
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, P. R. China
- Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, U.K
| | - Min Wu
- Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, U.K
| | - Sophie L Nixon
- Manchester Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, U.K
- Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, U.K
| | - Jonathan R Lloyd
- Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, U.K
| | - Naji M Bassil
- Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, U.K
| | - Ruixuan Gai
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, P. R. China
- Institute of Earth sciences, China University of Geosciences (Beijing), Beijing 100083, P. R. China
| | - Tianjing Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, P. R. China
- Institute of Earth sciences, China University of Geosciences (Beijing), Beijing 100083, P. R. China
| | - Zhan Su
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, P. R. China
- Institute of Earth sciences, China University of Geosciences (Beijing), Beijing 100083, P. R. China
| | - Huaming Guo
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, P. R. China
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, P. R. China
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8
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Zhang S, Peiffer S, Liao X, Yang Z, Ma X, He D. Sulfidation of ferric (hydr)oxides and its implication on contaminants transformation: a review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 816:151574. [PMID: 34798096 DOI: 10.1016/j.scitotenv.2021.151574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/05/2021] [Accepted: 11/05/2021] [Indexed: 06/13/2023]
Abstract
Rapid industrialization and urbanization have resulted in elevated concentrations of contaminants in the groundwaters and subsurface soils, posing a growing hazard to humans and ecosystems. The transformation of most contaminants is closely linked to the mineralogy of ferric (hydr)oxides. Sulfidation of ferric (hydr)oxides is one of the most significant biogeochemical reactions in the anoxic environments, causing reductive dissolution and recrystallization of ferric (hydr)oxides and further affecting the transformation of iron-associated contaminants. This paper provides a comprehensive review on the sulfidation process of ferric (hydr)oxides and the transformation of relevant contaminants. This review presents detailed reaction mechanisms between ferric (hydr)oxides and dissolved sulfide, and elucidates the factors (e.g. crystallinity of ferric (hydr)oxides, the ratio of sulfide concentration to the surface area concentration of ferric (hydr)oxides) that control the formation of surface associated Fe(II), iron sulfide minerals, as well as transformation of secondary minerals. Then, we summarized the transformation mechanisms of a variety of typical environmentally relevant contaminants existing in groundwater and subsurface soils, including heavy metals, metal(loid) oxyanions (arsenic, antimony, chromium), radionuclides (uranium, technetium), organic contaminants and phosphate/nitrate species. The general mechanisms of contaminant transformation involve a combination of release, reduction and re-adsorption/incorporation processes, the specific pathway of which is highly dependent on the properties of the contaminant itself and the extent of sulfidation. Moreover, the challenge of extending our knowledge towards in situ remediation, as well as further research needs are identified.
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Affiliation(s)
- Shaojian Zhang
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Stefan Peiffer
- BayCEER, Department of Hydrology, University of Bayreuth, D-95440 Bayreuth, Germany
| | - Xiaoting Liao
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Zhengheng Yang
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Xiaoming Ma
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Di He
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.
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9
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Neptunium and Uranium Interactions with Environmentally and Industrially Relevant Iron Minerals. MINERALS 2022. [DOI: 10.3390/min12020165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Neptunium (237Np) is an important radionuclide in the nuclear fuel cycle in areas such as effluent treatment and the geodisposal of radioactive waste. Due to neptunium’s redox sensitivity and its tendency to adsorb strongly to mineral phases, such as iron oxides/sulfides, the environmental mobility of Np can be altered significantly by a wide variety of chemical processes. Here, Np interactions with key iron minerals, ferrihydrite (Fe5O8H·4H2O), goethite (α-FeOOH), and mackinawite (FeS), are investigated using X-ray Absorption Spectroscopy (XAS) in order to explore the mobility of neptunyl(V) (Np(V)O2+) moiety in environmental (radioactive waste disposal) and industrial (effluent treatment plant) scenarios. Analysis of the Np LIII-edge X-ray Absorption Near-Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) showed that upon exposure to goethite and ferrihydrite, Np(V) adsorbed to the surface, likely as an inner-sphere complex. Interestingly, analysis showed that only the first two shells (Oax and Oeq) of the EXAFS could be modelled with a high degree of confidence, and there was no clear indication of Fe or carbonate in the fits. When Np(V)O2+ was added to a mackinawite-containing system, Np(V) was reduced to Np(IV) and formed a nanocrystalline Np(IV)O2 solid. An analogous experiment was also performed with U(VI)O22+, and a similar reduction was observed, with U(VI) being reduced to nanocrystalline uraninite (U(IV)O2). These results highlight that Np(V) may undergo a variety of speciation changes in environmental and engineered systems whilst also highlighting the need for multi-technique approaches to speciation determination for actinyl (for example, Np(V)O2+) species.
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10
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Townsend LT, Kuippers G, Lloyd JR, Natrajan LS, Boothman C, Mosselmans JFW, Shaw S, Morris K. Biogenic Sulfidation of U(VI) and Ferrihydrite Mediated by Sulfate-Reducing Bacteria at Elevated pH. ACS EARTH & SPACE CHEMISTRY 2021; 5:3075-3086. [PMID: 34825123 PMCID: PMC8607498 DOI: 10.1021/acsearthspacechem.1c00126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/17/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Globally, the need for radioactive waste disposal and contaminated land management is clear. Here, gaining an improved understanding of how biogeochemical processes, such as Fe(III) and sulfate reduction, may control the environmental mobility of radionuclides is important. Uranium (U), typically the most abundant radionuclide by mass in radioactive wastes and contaminated land scenarios, may have its environmental mobility impacted by biogeochemical processes within the subsurface. This study investigated the fate of U(VI) in an alkaline (pH ∼9.6) sulfate-reducing enrichment culture obtained from a high-pH environment. To explore the mobility of U(VI) under alkaline conditions where iron minerals are ubiquitous, a range of conditions were tested, including high (30 mM) and low (1 mM) carbonate concentrations and the presence and absence of Fe(III). At high carbonate concentrations, the pH was buffered to approximately pH 9.6, which delayed the onset of sulfate reduction and meant that the reduction of U(VI)(aq) to poorly soluble U(IV)(s) was slowed. Low carbonate conditions allowed microbial sulfate reduction to proceed and caused the pH to fall to ∼7.5. This drop in pH was likely due to the presence of volatile fatty acids from the microbial respiration of gluconate. Here, aqueous sulfide accumulated and U was removed from solution as a mixture of U(IV) and U(VI) phosphate species. In addition, sulfate-reducing bacteria, such as Desulfosporosinus species, were enriched during development of sulfate-reducing conditions. Results highlight the impact of carbonate concentrations on U speciation and solubility in alkaline conditions, informing intermediate-level radioactive waste disposal and radioactively contaminated land management.
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Affiliation(s)
- Luke T. Townsend
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, U.K.
| | - Gina Kuippers
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, U.K.
| | - Jonathan R. Lloyd
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, U.K.
| | - Louise S. Natrajan
- Centre
for Radiochemistry Research, Department of Chemistry, School of Natural
Sciences, The University of Manchester, Manchester M13 9PL, U.K.
| | - Christopher Boothman
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, U.K.
| | - J. Frederick W. Mosselmans
- Diamond
Light Source Ltd., Diamond
House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K.
| | - Samuel Shaw
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, U.K.
| | - Katherine Morris
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, U.K.
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11
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Townsend LT, Morris K, Harrison R, Schacherl B, Vitova T, Kovarik L, Pearce CI, Mosselmans JFW, Shaw S. Sulfidation of magnetite with incorporated uranium. CHEMOSPHERE 2021; 276:130117. [PMID: 34088087 DOI: 10.1016/j.chemosphere.2021.130117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 02/03/2021] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
Uranium (U) is a radionuclide of key environmental interest due its abundance by mass within radioactive waste and presence in contaminated land scenarios. Ubiquitously present iron (oxyhydr)oxide mineral phases, such as (nano)magnetite, have been identified as candidates for immobilisation of U via incorporation into the mineral structure. Studies of how biogeochemical processes, such as sulfidation from the presence of sulfate-reducing bacteria, may affect iron (oxyhydr)oxides and impact radionuclide mobility are important in order to underpin geological disposal of radioactive waste and manage radioactively contaminated land. Here, this study utilised a highly controlled abiotic method for sulfidation of U(V) incorporated into nanomagnetite to determine the fate and speciation of U. Upon sulfidation, transient release of U into solution occurred (∼8.6% total U) for up to 3 days, despite the highly reducing conditions. As the system evolved, lepidocrocite was observed to form over a period of days to weeks. After 10 months, XAS and geochemical data showed all U was partitioned to the solid phase, as both nanoparticulate uraninite (U(IV)O2) and a percentage of retained U(V). Further EXAFS analysis showed incorporation of the residual U(V) fraction into an iron (oxyhydr)oxide mineral phase, likely nanomagnetite or lepidocrocite. Overall, these results provide new insights into the stability of U(V) incorporated iron (oxyhydr)oxides during sulfidation, confirming the longer term retention of U in the solid phase under complex, environmentally relevant conditions.
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Affiliation(s)
- Luke T Townsend
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Katherine Morris
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Robert Harrison
- School of Mechanical, Aerospace & Civil Engineering, University of Manchester, Manchester, M13 9PL, UK
| | - Bianca Schacherl
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (KIT-INE), P.O. Box 3640, D-76021, Karlsruhe, Germany
| | - Tonya Vitova
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (KIT-INE), P.O. Box 3640, D-76021, Karlsruhe, Germany
| | - Libor Kovarik
- Pacific Northwest National Laboratory, Richland, WA, 99352, United States
| | - Carolyn I Pearce
- Pacific Northwest National Laboratory, Richland, WA, 99352, United States
| | - J Frederick W Mosselmans
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Samuel Shaw
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK.
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Abstract
Among all minerals, iron is one of the elements identified early by human beings to take advantage of and be used. The role of iron in human life is so great that it made an era in the ages of humanity. Pure iron has a shiny grayish-silver color, but after combining with oxygen and water it can make a colorful set of materials with divergent properties. This diversity sometimes appears ambiguous but provides variety of applications. In fact, iron can come in different forms: zero-valent iron (pure iron), iron oxides, iron hydroxides, and iron oxide hydroxides. By taking these divergent materials into the nano realm, new properties are exhibited, providing us with even more applications. This review deals with iron as a magic element in the nano realm and provides comprehensive data about its structure, properties, synthesis techniques, and applications of various forms of iron-based nanostructures in the science, medicine, and technology sectors.
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13
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Wu J, Zhao J, Hou J, Xing B. The Fate of p-Nitrophenol in Goethite-Rich and Sulfide-Containing Dynamic Anoxic/Oxic Environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:9427-9436. [PMID: 32628455 DOI: 10.1021/acs.est.0c02486] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Reaction mechanisms between sulfide and iron (hydr)oxides are well-documented; however, the effect of sulfidation of iron (hydr)oxides on the fate of contaminants in dynamic anoxic/oxic environments is largely overlooked. Taking p-nitrophenol (p-NP) as a targeted contaminant, we studied its fate during the sulfidation of goethite in dynamic anoxic/oxic environments. In anoxic environments, the adsorbed p-NP on goethite was sharply released in the presence of S(-II) at two different concentrations (denoted as G1 and G2, respectively) due to lower affinity of p-NP on ═Fe-SH than ═Fe-OH. Then, the desorbed p-NP in the G1 system was completely reduced to p-aminophenol (p-AP), while negligible change of p-NP concentration occurred in the G2 system, which was ascribed to the generation of Fe(II)-bound goethite with high reactivity toward p-NP at G1. When the environments shifted to oxic conditions, the structural Fe(II) of FeS produced plenty of •OH in G1 and G2 through Fenton-like reaction, which attacked p-NP and p-AP toward complete degradation. Our study demonstrated that sulfidation of goethite and shift of redox conditions could be crucial factors in controlling the fate of p-NP, which needs to be considered when predicting the environmental fate of p-NP.
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Affiliation(s)
- Jun Wu
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
- CAS Key Laboratory for Urban Pollutant Conversion, Department of Applied Chemistry, University of Science & Technology of China, Hefei, 230026, China
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Jian Zhao
- Institute of Coastal Environmental Pollution Control, and Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
| | - Jun Hou
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, Massachusetts 01003, United States
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14
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Yu G, Fu F, Ye C, Tang B. Behaviors and fate of adsorbed Cr(VI) during Fe(II)-induced transformation of ferrihydrite-humic acid co-precipitates. JOURNAL OF HAZARDOUS MATERIALS 2020; 392:122272. [PMID: 32086091 DOI: 10.1016/j.jhazmat.2020.122272] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 02/05/2020] [Accepted: 02/10/2020] [Indexed: 06/10/2023]
Abstract
The mobility of Cr(VI) in the environment is affected by the transformation of ferrihydrite (Fh) and ferrihydrite-humic acid co-precipitates (Fh-HA). However, the impacts of Fe(II)-induced transformation of Fh and Fh-HA on the mobility, speciation and partitioning of associated Cr(VI) remain unclear. In this study, the behaviors of adsorbed Cr(VI) during Fh and Fh-HA aging at 70 °C for 9 days (pH0 = 3.0 and 7.0) in the absence and presence of Fe(II) were studied. Results revealed that the main speciation of Cr(VI) after transformation was non-desorbable Cr and its formation involved the following pathways. Firstly, Fe(II) (0.2 and 2.0 mM) induced the transformation of Fh-HA to hematite and goethite, promoting the structural incorporation of adsorbed Cr into hematite and goethite via complexation. Secondly, under neutral condition (pH0 = 7.0), the low concentration of Fe(II) (0.2 mM) could not reduce completely Cr(VI) to Cr(III) and thus residual Cr(VI) was incorporated into the Cr(III)-Fe(III) co-precipitates. Thirdly, coprecipitated humic acid not only reduced Cr(VI) to Cr(III) via polysaccharide, but also formed complexes with incorporated Cr through carboxylic groups to sequester Cr. Our results demonstrate that Fe(II)-induced transformation of Fh-HA exerts major influences on associated Cr(VI) speciation and partitioning.
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Affiliation(s)
- Guangda Yu
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou, 510006, China
| | - Fenglian Fu
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou, 510006, China.
| | - Chujia Ye
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou, 510006, China
| | - Bing Tang
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou, 510006, China
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15
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Li M, Liu H, Chen T, Chen D, Wang C, Wei L, Wang L. Efficient U(VI) adsorption on iron/carbon composites derived from the coupling of cellulose with iron oxides: Performance and mechanism. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 703:135604. [PMID: 31771849 DOI: 10.1016/j.scitotenv.2019.135604] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/11/2019] [Accepted: 11/16/2019] [Indexed: 06/10/2023]
Abstract
Novel iron/carbon composites were successfully prepared via coupling of cellulose with iron oxides (e.g. α-FeOOH, Fe2O3 and Fe(NO3)3·9H2O) at different temperatures under nitrogen atmosphere. Characterization by various techniques implied that chemical interaction between cellulose and Fe3O4/Fe0 existed in the as-prepared iron/carbon composites. The site of interaction between cellulose and iron precursors was illustrated (mainly combined with COO-). The self-reduction of Fe3+ to Fe2+ or even Fe0 and the interaction between carbon and Fe3O4/Fe0 in the calcination process realized the strong magnetism of the composites. Batch experiments and spectroscopic techniques indicated that the maximum adsorption capacity of MHC-7 for U(VI) (105.3 mg/g) was significantly higher than that of MGC-7 (86.0 mg/g) and MFC-7 (79.0 mg/g), indicating that Fe2O3 can be regarded as the remarkable iron resource for the iron/carbon composites. XPS results revealed that the oxygen-containing groups were responsible for the adsorption process of U(VI) on iron/carbon composites, and the adsorption of carbon and reduction of Fe0/Fe3O4 toward U(VI) were synergistic during the reaction process. In addition, the iron/carbon composites exhibited a good recyclability, recoverability and stability for U(VI) adsorption in the regeneration experiments. These findings demonstrated that the iron/carbon composites can be considered as valuable adsorbents in environmental cleanup and the Fe2O3 was a promising iron resource for the preparation of iron/carbon composites.
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Affiliation(s)
- Mengxue Li
- Key Laboratory of Nano-minerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei 230009, China; Institute of Environmental Mineral and Material, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Haibo Liu
- Key Laboratory of Nano-minerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei 230009, China; Institute of Environmental Mineral and Material, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China.
| | - Tianhu Chen
- Key Laboratory of Nano-minerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei 230009, China; Institute of Environmental Mineral and Material, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Dong Chen
- Key Laboratory of Nano-minerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei 230009, China; Institute of Environmental Mineral and Material, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Can Wang
- Key Laboratory of Nano-minerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei 230009, China; Institute of Environmental Mineral and Material, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Lin Wei
- Key Laboratory of Nano-minerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei 230009, China; Institute of Environmental Mineral and Material, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Lingkai Wang
- Key Laboratory of Nano-minerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei 230009, China; Institute of Environmental Mineral and Material, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
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16
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Townsend LT, Shaw S, Ofili NER, Kaltsoyannis N, Walton AS, Mosselmans JFW, Neill TS, Lloyd JR, Heath S, Hibberd R, Morris K. Formation of a U(VI)-Persulfide Complex during Environmentally Relevant Sulfidation of Iron (Oxyhydr)oxides. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:129-136. [PMID: 31838844 DOI: 10.1021/acs.est.9b03180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Uranium is a risk-driving radionuclide in both radioactive waste disposal and contaminated land scenarios. In these environments, a range of biogeochemical processes can occur, including sulfate reduction, which can induce sulfidation of iron (oxyhydr)oxide mineral phases. During sulfidation, labile U(VI) is known to reduce to relatively immobile U(IV); however, the detailed mechanisms of the changes in U speciation during these biogeochemical reactions are poorly constrained. Here, we performed highly controlled sulfidation experiments at pH 7 and pH 9.5 on U(VI) adsorbed to ferrihydrite and investigated the system using geochemical analyses, X-ray absorption spectroscopy (XAS), and computational modeling. Analysis of the XAS data indicated the formation of a novel, transient U(VI)-persulfide complex as an intermediate species during the sulfidation reaction, concomitant with the transient release of uranium to the solution. Extended X-ray absorption fine structure (EXAFS) modeling showed that a persulfide ligand was coordinated in the equatorial plane of the uranyl moiety, and formation of this species was supported by computational modeling. The final speciation of U was nanoparticulate U(IV) uraninite, and this phase was evident at 2 days at pH 7 and 1 year at pH 9.5. Our identification of a new, labile U(VI)-persulfide species under environmentally relevant conditions may have implications for U mobility in sulfidic environments pertinent to radioactive waste disposal and contaminated land scenarios.
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Affiliation(s)
| | | | | | | | | | - J Frederick W Mosselmans
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K
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Wu J, Zeng RJ. In Situ Preparation of Stabilized Iron Sulfide Nanoparticle-Impregnated Alginate Composite for Selenite Remediation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:6487-6496. [PMID: 0 DOI: 10.1021/acs.est.7b05861] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Affiliation(s)
- Jun Wu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- CAS Key Laboratory for Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, PR China
| | - Raymond Jianxiong Zeng
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- CAS Key Laboratory for Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, PR China
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18
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Majumder ELW, Wall JD. Uranium Bio-Transformations: Chemical or Biological Processes? ACTA ACUST UNITED AC 2017. [DOI: 10.4236/ojic.2017.72003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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