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Tang Q, Xu Z, Tan Q, Shi X, Wu W, Pan D. Insight into Impact of Phosphate on the Cotransport and Corelease of Eu(III) with Bentonite Colloids in Saturated Quartz Columns. JOURNAL OF HAZARDOUS MATERIALS 2024; 461:132572. [PMID: 37742375 DOI: 10.1016/j.jhazmat.2023.132572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/12/2023] [Accepted: 09/16/2023] [Indexed: 09/26/2023]
Abstract
Understanding the fate and transport of radionuclides in porous media reduces the risk of contaminating soils and groundwater systems. While the cotransport of bentonite colloids (BC) with radionuclides in saturated media is well documented, the role of phosphate (P) in the colloid-driven transport of radionuclides in saturated porous media is still unaddressed; in particular, phosphate increases the mobilities of radionuclides in porous media, which should be subjected to an environmental risk assessment and model construction. In this work, the effects of phosphate on the transport and release of Eu(III) in different colloid systems (P-Eu(III), P-BC, P-BC-Eu(III)) was investigated with a fundamental colloid chemistry approach and a range of characterization techniques. The results showed that intrinsic europium colloids with size of 685 nm were formed by precipitation with phosphate, which affected the mobility of Eu(III) due to colloid stability and physical straining. Phosphate enhanced BC and BC-Eu(III) transport, and a high phosphate concentration promoted BC transport by eliminating physical straining and enhancing the electrostatic repulsions. The crystal structure of EuPO4 was not destroyed by the subsequent introduction of BC, which carried EuPO4 for further migration. However, when phosphate, bentonite and Eu(III) coexisted in a colloid suspension, the phosphate promoted Eu(III) transport by preferentially interacting with the BC to form ternary BC-P-Eu(III) pseudo-colloids rather than forming the intrinsic EuPO4 colloids. The synergetic role of P and BC on Eu(III) transport involved a relatively complex process and was not a simply additive effect. The findings in this work highlight the significance of phosphate in controlling the fate and transport of Ln(III)/Am(III) radionuclides in the presence of intrinsic colloids and pseudo-colloids in P-rich colloid-bearing environments.
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Affiliation(s)
- Qingfeng Tang
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Zhen Xu
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China; MOE Frontiers Science Center for Rare Isotopes, Lanzhou University, Lanzhou 730000, China.
| | - Qi Tan
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Xingyi Shi
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Wangsuo Wu
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China; MOE Frontiers Science Center for Rare Isotopes, Lanzhou University, Lanzhou 730000, China
| | - Duoqiang Pan
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China; MOE Frontiers Science Center for Rare Isotopes, Lanzhou University, Lanzhou 730000, China.
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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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Bryukhanov AL, Khijniak TV. The Application of Sulfate-Reducing Bacteria in the Bioremediation of Heavy Metals and Metalloids. APPL BIOCHEM MICRO+ 2022. [DOI: 10.1134/s0003683822100039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
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Chen S, Cheng Y, Zeng Q, Zhu T, Li F, Lan T, Yang Y, Yang J, Liao J, Liu N. Accurate determination of tetravalent uranium reduced by microorganisms via a potentiometric titration procedure. RADIOCHIM ACTA 2022. [DOI: 10.1515/ract-2022-0037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Although bioreduction induced by microorganisms has been considered to play an important role in the chemical and migration behaviors of uranium in nature, the accurate determination of tetravalent uranium reduced by microorganisms is still difficult to achieve. In this work, potentiometric titration via K2Cr2O7 was used to quantitatively determine the microorganism reduced tetravalent uranium (U(IV)) for the first time. By evaluating the influence of microorganism substance content on the titration of U(IV), the appropriate determination range of U(IV) and biomass was confirmed, and U(IV) induced by bioreduction in three microorganisms was determined. With this method, U(IV) of more than 0.12 mg in microorganisms can be quantitatively measured with an accuracy of 2.2% and a precision of 1.3%, which has been established with the premise that the pretreatment biomass and quantity of U(IV) are in an appropriate range. Compared with the estimated values via the changes in hexavalent uranium (U(VI)) concentration in the bioreduction system, the results obtained by this method can more accurately reflect the quantity of U(IV) in microorganisms. This work can help us to better understand the bioreduction behavior of uranium in the environment.
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Affiliation(s)
- Shunzhang Chen
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Yanxia Cheng
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Qian Zeng
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Ting Zhu
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Feize Li
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Tu Lan
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Yuanyou Yang
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Jijun Yang
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Jiali Liao
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Ning Liu
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
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