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1.
Sci Total Environ ; 773: 144982, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33592458

RESUMO

Combating microbial survival on dry surfaces contributes to improving public health in indoor environments (clinical and industrial settings) and extends to the natural environment. For vegetative bacteria at solid-air interfaces, lack of water impacts cellular response, and acclimation depends on community support in response to ecological processes. Gaining insights about important ecological processes leading to inhibition of microbial survival under extreme conditions, such as vicinity of highly radioactive nuclear waste, is key for improving engineering designs. Canada plans to store used nuclear fuel and radioactive waste in a deep geological repository (DGR) with a multiple-barrier system constructed at an approximate depth of 500 m. Microorganisms in highly compacted bentonite surrounding used fuel containers will be challenged by high pressure, temperature, and radiation, as well as limited water and nutrients. Thus, it is difficult to estimate microbial activities, given that the prime concern for a microbial community is survival, and energy expenditure is regulated. To enable preventive measures and for risk evaluation, a deeper understanding of community-based survival strategies of bacterial cells exposed to air (gaseous phase) during prolonged periods of desiccation is required. An in-depth review of collective studies that assess microbial survival and persistence during desiccation is presented here to augment and direct our prior knowledge about tactics used by bacteria for survival at interfaces in hostile natural environments including and similar to a DGR.


Assuntos
Microbiota , Resíduos Radioativos , Bactérias , Bentonita/análise , Canadá , Resíduos Radioativos/análise
2.
J Hazard Mater ; 408: 124600, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33339698

RESUMO

Compacted bentonites are one of the best sealing and backfilling clays considered for use in Deep Geological Repositories of radioactive wastes. However, an in-depth understanding of their behavior after placement in the repository is required, including if the activity of indigenous microorganisms affects safety conditions. Here we provide an optimized phenol:chloroform based protocol that facilitates higher DNA-yields when other methods failed. To demonstrate the efficiency of this method, DNA was extracted from acetate-treated bentonites compacted at 1.5 and 1.7 g/cm3 densities after 24 months anoxic incubation. Among the 16S rRNA gene sequences identified, those most similar to taxa mediating biogeochemical sulfur cycling included sulfur oxidizing (e.g., Thiobacillus, and Sulfurimonas) and sulfate reducing (e.g., Desulfuromonas and Desulfosporosinus) bacteria. In addition, iron-cycling populations included iron oxidizing (e.g., Thiobacillus and Rhodobacter) plus reducing taxa (e.g., Geobacillus). Genera described for their capacity to utilize acetate as a carbon source were also detected such as Delftia and Stenotrophomonas. Lastly, microscopic analyses revealed pores and cracks that could host nanobacteria or spores. This study highlights the potential role of microbial driven biogeochemical processes in compacted bentonites and the effect of high compaction on microbial diversity in Deep Geological Repositories.


Assuntos
Resíduos Radioativos , Bactérias/genética , Bentonita , Argila , RNA Ribossômico 16S/genética , Resíduos Radioativos/análise
3.
J Environ Radioact ; 223-224: 106389, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32950913

RESUMO

In arid climate, economic activities at the territory of the "Atomic" lake is one of the topical issues for the Semipalatinsk test site (STS). Hence, the boundaries of areas with radionuclides contamination, which correspond to the level of radioactive wastes at the territory adjacent to the "Atomic" lake of STS, are to be determined. The territory around the lake is used for cattle breeding and the water of the "Atomic" lake that is the one large water source is used for livestock watering. It is important to develop measures that will limit possible negative impact on population and environment. In results of the conducted research were developed measures consisting of remediation and access limitation to the stockpile of soils with contamination level corresponding to the level of radioactive waste (RW).


Assuntos
Lagos , Monitoramento de Radiação , Resíduos Radioativos , Animais , Bovinos , Resíduos Radioativos/análise , Radioisótopos/análise , Poluentes Radioativos do Solo/análise
4.
Chemosphere ; 254: 126859, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957279

RESUMO

Understanding the long-term fate, stability, and bioavailability of uranium (U) in the environment is important for the management of nuclear legacy sites and radioactive wastes. Analysis of U behavior at natural analogue sites permits evaluation of U biogeochemistry under conditions more representative of long-term equilibrium. Here, we have used bulk geochemical and microbial community analysis of soils, coupled with X-ray absorption spectroscopy and µ-focus X-ray fluorescence mapping, to gain a mechanistic understanding of the fate of U transported into an organic-rich soil from a pitchblende vein at the UK Needle's Eye Natural Analogue site. U is highly enriched in the Needle's Eye soils (∼1600 mg kg-1). We show that this enrichment is largely controlled by U(VI) complexation with soil organic matter and not U(VI) bioreduction. Instead, organic-associated U(VI) seems to remain stable under microbially-mediated Fe(III)-reducing conditions. U(IV) (as non-crystalline U(IV)) was only observed at greater depths at the site (>25 cm); the soil here was comparatively mineral-rich, organic-poor, and sulfate-reducing/methanogenic. Furthermore, nanocrystalline UO2, an alternative product of U(VI) reduction in soils, was not observed at the site, and U did not appear to be associated with Fe-bearing minerals. Organic-rich soils appear to have the potential to impede U groundwater transport, irrespective of ambient redox conditions.


Assuntos
Água Subterrânea/química , Resíduos Radioativos/análise , Solo/química , Urânio/análise , Poluentes Radioativos da Água/análise , Compostos Férricos , Microbiologia do Solo , Urânio/química , Compostos de Urânio/análise , Espectroscopia por Absorção de Raios X
5.
Environ Sci Pollut Res Int ; 27(20): 25057-25068, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32347488

RESUMO

In the Chinese high-level radioactive waste geological disposal program, Gaomiaozi (GMZ) bentonite has been selected as the potential buffer/backfill material. After the closure of the repository, the Ca-OH-type alkaline solution (evolved cement water) released by cement degradation may last for more than 100,000 years. The bentonite will undergo the corrosion of evolved cement water (ECW) for a long period. This work focuses on the sorption property of GMZ bentonite altered by ECW. Firstly, the corrosion experiments on compacted GMZ specimens with the dry density of 1.70 Mg/m3 were carried out under constant volume conditions at two temperatures. Then, the sorption of europium (Eu (III)) onto the corroded GMZ bentonite was studied by batch experiments. The results of batch sorption tests indicate that the altered GMZ bentonite keeps an effective removal property with the uptake of Eu (III) more than 99%. The effect of high-temperature conditions of the repository on the sorption property of bentonite is not significant. The results also suggest that the evolved cement water presents no detrimental effect on the long-term adsorption performance of bentonite even under higher temperature conditions.


Assuntos
Bentonita , Resíduos Radioativos/análise , Adsorção , Európio , Temperatura , Água
6.
J Contam Hydrol ; 230: 103622, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32044157

RESUMO

During the long term operation of a disposal repository, gas will be inevitably generated. Determination of gas permeability of compacted bentonite is of great importance for the safety assessment of the engineered barrier system. In the present work, the steady-state and residual pressure methods were employed to determine the gas permeability of GaoMiaoZi (GMZ) bentonite with consideration of variations in liquid saturation, dry density and confining pressure. Results show that, gas migration in saturated GMZ bentonite was mainly controlled by diffusion with an effective gas permeability of 1E-23 m2 - 1E-25 m2. While in unsaturated GMZ bentonite, significant gas flow rates could be observed, which increased stably with the increase of gas injection pressure. Klinkenberg effect was significant when gas flow through GMZ bentonite. The Klinkenberg corrected gas permeability decreased by 3.5-5.5 orders of magnitude as the liquid saturation increased from 10% to 70%. A decreasing magnitude of 1-2 orders in Klinkenberg corrected gas permeability was presented with the dry density increased from 1.5 Mg/m3 and 1.7 Mg/m3. The Klinkenberg corrected gas permeability decreased by 0-1 orders of magnitude as the confining pressure increased from 3 MPa to 7 MPa. By using the accessible porosity, gas measured intrinsic permeability could be determined with values ranged between 1E-15 m2 to 4E-15 m2, which was higher than the water measured one by 5 orders of magnitude. Additionally, a generalized power law was successfully adopted in this study to describe the evolution of gas relative permeability with the liquid saturation. Overall, the effective gas permeability, Klinkenberg corrected gas permeability, intrinsic and relative permeability determined in this study provided a comprehensive perspective to assess the buffering property of GMZ bentonite in multi-physical field coupling environment. The parameters obtained can be adopted in further simulation works for long-term safety analysis of the disposal repository from the viewpoint of gas migration.


Assuntos
Bentonita , Resíduos Radioativos/análise , Permeabilidade , Porosidade , Água
8.
Health Phys ; 118(1): 1-17, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31703016

RESUMO

A dose-based compliance methodology was developed for Waste Control Specialists, LLC, low-level radioactive waste facility in Andrews, Texas, that allows routine environmental measurement data to be evaluated not only at the end of a year to determine regulatory compliance, but also throughout the year as new data become available, providing a continuous assessment of the facility. The first step in the methodology is a screening step to determine the potential presence of site emissions in the environment, and screening levels are established for each environmental media sampled. The screening accounts for spatial variations observed in background for soil and temporal fluctuations observed in background for air. For groundwater, the natural activity concentrations in groundwater wells at the facility are highly variable, and therefore the methodology uses ratios for screening levels. The methodology compares the ratio of gross alpha to U + U to identify potentially abnormal alpha activity and the ratio of U to U to identify the potential presence of depleted uranium. Compliance evaluation is conducted for any samples that fail the screening step. Compliance evaluation uses the radionuclide-specific measurements to first determine (1) if the dose exceeds the background dose and if so, (2) the dose consequences, so that the appropriate investigation or action occurs. The compliance evaluation is applied to all environmental samples throughout the year and on an annual basis to determine regulatory compliance. The methodology is implemented in a cloud-based software application that is also made accessible to the regulator. The benefits of the methodology over the existing system are presented.


Assuntos
Monitoramento Ambiental/normas , Modelos Teóricos , Monitoramento de Radiação/métodos , Proteção Radiológica/normas , Resíduos Radioativos/análise , Urânio/análise , Instalações de Eliminação de Resíduos/normas , Poluentes Radioativos do Ar/análise , Água Subterrânea/química , Humanos , Proteção Radiológica/legislação & jurisprudência , Instalações de Eliminação de Resíduos/legislação & jurisprudência , Poluentes Radioativos da Água/análise
9.
Chemosphere ; 241: 124964, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31604195

RESUMO

Around former glass factories in south eastern Sweden, there are dozens of dumps whose radioactivity and physico-chemical properties were not investigated previously. Thus, radiometric and physico-chemical characteristics of waste at Madesjö glass dump were studied to evaluate pre-recycling storage requirements and potential radiological and environmental risks. The material was sieved, hand-sorted, leached and scanned with X-Ray Fluorescence (XRF). External dose rates and activity concentrations of Naturally Occurring Radioactive Materials from 238U, 232Th series and 40K were also measured coupled with a radiological risk assessment. Results showed that the waste was 95% glass and dominated by fine fractions (<11.3 mm) at 43.6%. The fine fraction had pH 7.8, 2.6% moisture content, 123 mg kg-1 Total Dissolved Solids, 37.2 mg kg-1 Dissolved Organic Carbon and 10.5 mg kg-1 fluorides. Compared with Swedish EPA guidelines, the elements As, Cd, Pb and Zn were in hazardous concentrations while Pb leached more than the limits for inert and non-hazardous wastes. With 40K activity concentration up to 3000 Bq kg-1, enhanced external dose rates of 40K were established (0.20 µSv h-1) although no radiological risk was found since both External Hazard Index (Hex) and Gamma Index (Iγ) were <1. The glass dump needs remediation and storage of the waste materials under a safe hazardous waste class 'Bank Account' storage cell as a secondary resource for potential future recycling.


Assuntos
Fenômenos Químicos , Vidro/análise , Poluentes Radioativos/análise , Resíduos Radioativos/análise , Resíduos/análise , Resíduos Perigosos , Radioisótopos de Potássio/análise , Reciclagem , Espectrometria por Raios X , Suécia , Tório/análise , Urânio/análise
10.
Radiat Prot Dosimetry ; 186(2-3): 306-309, 2019 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-31832660

RESUMO

Decommissioning of nuclear building structures usually leads to large amounts of low-level radioactive waste. Using a reliable method to determine the contamination depth, it is indispensable prior to the start of decontamination works and for minimising the radioactive waste volume and the total workload. This paper deals with the possibilities of determination of depth distribution of activity of 137Cs and depth of contamination. The method described in this paper is based on concrete core sampling and laboratory gamma-ray spectroscopy measurements.


Assuntos
Radioisótopos de Césio/análise , Materiais de Construção/análise , Descontaminação/métodos , Monitoramento de Radiação/métodos , Cinza Radioativa/análise , Resíduos Radioativos/análise , Poluentes Radioativos do Solo/análise , Humanos , Espectrometria gama
13.
Mar Pollut Bull ; 146: 454-461, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426180

RESUMO

This work is a first contribution to the knowledge of natural radionuclides (226Ra, 238U, 40K, and 232Th) activities in phosphate rock (NORM), phosphogypsum, and phosphogypsum foam (TENORM) from the coastal fertilizer plants of Gabes (Southeastern Tunisia) and the assessment of their radiation hazards on human health and the surrounding environment. In the three studied materials, activities were found to be in the range of 35.4 (40K)-375.1 (226Ra), 10.0 (40K)-220.2 (226Ra), and 79.2 (232Th)-1168.6 Bq kg-1 (226Ra), respectively. Considering the studied radionuclides and materials, the corresponding decreasing activity orders were found to be 226Ra > 238U > 40K > 232Th and PGF > PR > PG, respectively. All human health hazard indices exceeded the worldwide recommended safety limits, which show that the workers in Gabes phosphate fertilizer plants as well as the neighboring human community may potentially be exposed to significant radiation, which may cause several diseases and malformations. It is therefore recommended to avoid and/or reduce the potential fertilizer industry radioactive impact in the area.


Assuntos
Fertilizantes/análise , Resíduos Industriais/análise , Fosfatos/química , Resíduos Radioativos/análise , Radioisótopos/análise , Sulfato de Cálcio/análise , Sulfato de Cálcio/química , Humanos , Mar Mediterrâneo , Fósforo/análise , Fósforo/química , Medição de Risco , Tunísia
14.
Sci Total Environ ; 692: 219-232, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31349163

RESUMO

The multi-barrier deep geological repository system is currently considered as one of the safest option for the disposal of high-level radioactive wastes. Indigenous microorganisms of bentonites may affect the structure and stability of these clays through Fe-containing minerals biotransformation and radionuclides mobilization. The present work aimed to investigate the behavior of bentonite and its bacterial community in the case of a uranium leakage from the waste containers. Hence, bentonite microcosms were amended with uranyl nitrate (U) and glycerol-2-phosphate (G2P) and incubated aerobically for 6 months. Next generation 16S rRNA gene sequencing revealed that the bacterial populations of all treated microcosms were dominated by Actinobacteria and Proteobacteria, accounting for >50% of the community. Additionally, G2P and nitrate had a remarkable effect on the bacterial diversity of bentonites by the enrichment of bacteria involved in the nitrogen and carbon biogeochemical cycles (e.g. Azotobacter). A significant presence of sulfate-reducing bacteria such as Desulfonauticus and Desulfomicrobium were detected in the U-treated microcosms. The actinobacteria Amycolatopsis was enriched in G2P­uranium amended bentonites. High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy analyses showed the capacity of Amycolatopsis and a bentonite consortium formed by Bradyrhizobium-Rhizobium and Pseudomonas to precipitate U as U phosphate mineral phases, probably due to the phosphatase activity. The different amendments did not affect the mineralogy of the bentonite pointing to a high structural stability. These results would help to predict the impact of microbial processes on the biogeochemical cycles of elements (N and U) within the bentonite barrier under repository relevant conditions and to determine the changes in the microbial community induced by a uranium release.


Assuntos
Bactérias/metabolismo , Bentonita/análise , Glicerofosfatos/metabolismo , Microbiota/efeitos dos fármacos , Resíduos Radioativos/análise , Urânio/metabolismo , Bactérias/classificação
15.
Environ Sci Pollut Res Int ; 26(24): 25235-25246, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31256394

RESUMO

We explored the effect of the presence or absence of humic acid (HA) on the sorption behaviour of Sr onto soil. We examined three different experimental cases for Sr sorption: (1) sorption in the presence of only colloidal HA, (2) sorption in the presence of only soil and (3) sorption in the presence of both colloidal HA and soil (HS). A batch technique was used to study the influencing factors, including the amount of colloidal HA, solid content, pH, initial concentration of Sr and contact time. The experiments showed that the influencing factors significantly affected the sorption process. For example, in the case of soil and HS, the sorption percentage increased rapidly with increasing solid content at m/V < 20 g/L, changing from 8.35% and 37.54% to 49.09% and 77.03%, respectively. Moreover, scanning electron microscopy and Fourier transform infrared spectroscopy were used to characterize samples. The kinetics and isotherms of Sr were best described by the pseudo-second-order and Langmuir models, which indicated that the process was controlled by chemisorption and uniform monolayer sorption with constant energy on the outer surface. These findings provide valuable information for predicting strontium migration in radioactive waste disposal sites.


Assuntos
Coloides/química , Substâncias Húmicas , Resíduos Radioativos/análise , Poluentes do Solo/química , Estrôncio/química , Instalações de Eliminação de Resíduos , Adsorção , Geologia , Cinética , Radioatividade , Solo/química , Poluentes do Solo/análise , Espectroscopia de Infravermelho com Transformada de Fourier
16.
Environ Pollut ; 252(Pt B): 1491-1499, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31265960

RESUMO

Understanding the influence of colloids on radionuclide migration is of significance to evaluate environmental risks for radioactive waste disposals. In order to formulate an appropriate modelling framework that can quantify and interpret the anomalous transport of Strontium (Sr) in the absence and presence of colloids, the continuous time random walk (CTRW) approach is implemented in this work using available experimental information. The results show that the transport of Sr and its recovery are enhanced in the presence of colloids. The causes can be largely attributed to the trap-release processes, e.g. electrostatic interactions of Sr, colloids and natural sediments, and differences in pore structures, which gave rise to the varying interstitial velocities of dissolved and, if any, colloid-associated Sr. Good agreement between the CTRW simulations and the column-scale observations is demonstrated. Regardless of the presence of colloids, the CTRW modelling captures the characteristics of non-Fickian anomalous transport (0 < ß < 2) of Sr. In particular, a range of 0 < ß < 1, corresponding to the cases with greater recoveries, reveal strongly non-Fickian transport with distinctive earlier arrivals and tailing effects, likely due to the physicochemical heterogeneities, i.e. the repulsive interactions and/or the macro-pores originating from local heterogeneities. The results imply that colloids can increase the Sr transport as a barrier of Sr sorption onto sediments herein, apart from often being carriers of sored radionuclides in aqueous phase. From a modelling perspective, the findings show that the established CTRW model is valid for quantifying the non-Fickian and promoted transport of Sr with colloids.


Assuntos
Coloides/química , Resíduos Radioativos/análise , Eliminação de Resíduos/métodos , Poluentes Radioativos do Solo/análise , Estrôncio/análise , Poluentes Radioativos da Água/análise , Radioisótopos/análise
17.
J Environ Radioact ; 205-206: 61-71, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31102907

RESUMO

Assessments of the environmental impact of C-14 disposal often assume that C-14 is converted into gases that are able to migrate to the surface, where they pose a radiological risk. However, uncertainties, associated with the long-term release of C-14 from graphite and the evolution in the post-closure environment of a geological disposal facility (GDF), exist. In this paper, an integrated modelling framework has been developed to investigate these uncertainties. The modelling framework consists of a biogeochemical near field model which interfaces with a geosphere/biosphere model and it is verified by comparing the results to those obtained from other models. A sensitivity analysis discloses that a faster mid chain scission rate of stopped cellulose about four orders of magnitude assesses a twice higher effective dose. In another scenario, which is related to the control of microbial activity by pH and the availability of carbon dioxide to microbes, the effective dose is two orders of magnitude higher compared with a reference scenario. This modelling work illustrates also the importance of far field parameters, such as the rock permeability and the release area of gas pathway, to the assessment of effective dose.


Assuntos
Radioisótopos de Carbono/análise , Monitoramento de Radiação , Resíduos Radioativos/análise , Instalações de Eliminação de Resíduos , Meio Ambiente , Modelos Teóricos , Doses de Radiação , Medição de Risco
18.
Health Phys ; 117(4): 378-387, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30958804

RESUMO

Waterborne releases to the Techa River from the Mayak plutonium facility in Russia during 1949-1956 resulted in significant doses to persons living downstream. The dosimetry system Techa River Dosimetry System-2016D has been developed, which provides individual doses of external and internal exposure for the members of the Techa River cohort and other persons who were exposed to releases of radioactive material to the Southern Urals. The results of computation of individual doses absorbed in red bone marrow and extraskeletal tissues for the Techa River cohort members (29,647 persons) are presented, which are based on residence histories on the contaminated Techa River and the East Urals Radioactive Trace, which was formed in 1957 as a result of the Kyshtym Accident. Available Sr body-burden measurements and available information on individual household locations have been used for refinement of individual dose estimates. Techa River Dosimetry System-2016D-based dose estimates will be used for verification of risk of low-dose-rate effects of ionizing radiation in the Techa River cohort.


Assuntos
Exposição Ambiental/análise , Monitoramento de Radiação/métodos , Resíduos Radioativos/análise , Rios/química , Radioisótopos de Estrôncio/análise , Poluentes Radioativos da Água/análise , Carga Corporal (Radioterapia) , Estudos de Coortes , Feminino , Humanos , Masculino , Doses de Radiação , Radioisótopos de Estrôncio/farmacocinética , Distribuição Tecidual , Poluentes Radioativos da Água/farmacocinética
19.
Radiat Prot Dosimetry ; 185(4): 494-506, 2019 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-30989182

RESUMO

Activity concentrations of 238U, 232Th and 40K in raw and waste petroleum materials (Egypt and Kuwait) were measured using gamma ray spectrometer. The average values of 226Ra, 232Th and 40K were 21.1 ± 3.2, 7.6 ± 1.3 and 88.4 ± 8.2 Bq kg-1 for Egyptian samples while for Kuwaiti samples, they were 25.2 ± 3.4, 6.1 ± 2.2 and 67.8 ± 6.4 Bq kg-1, respectively. All samples had activity less than the exemption level recommended by the International Atomic Energy Agency. Moreover, radiological indices of radium equivalent, external, internal, alpha and gamma indices and radiation dose as well were calculated and their values were lower than the recommended regulatory limits. Thus, radiation exposure to petroleum materials did not present a significant radiological hazard.


Assuntos
Petróleo , Resíduos Radioativos/análise , Rádio (Elemento)/análise , Eliminação de Resíduos/métodos , Poluentes Radioativos do Solo/análise , Partículas alfa , Egito , Raios gama , Kuweit , Radioisótopos de Potássio/análise , Doses de Radiação , Monitoramento de Radiação , Radiografia , Areia , Esgotos , Espectrometria gama , Tório/análise , Urânio/análise
20.
Chemosphere ; 224: 776-785, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30851529

RESUMO

A simple one-step approach for fabricating copper ferrocyanide-embedded magnetic hydrogel beads (CuFC-MHBs) was designed, and the beads were applied to the effective removal of cesium (Cs) and then magnetically separated from water. The polyvinyl alcohol (PVA)-coated CuFC (PVA-CuFC) was first synthesized using PVA as a stabilizer and subsequently embedded in magnetic hydrogel beads made of a cross-linked network between the PVA and magnetic iron oxide nanoparticles that was prepared through the simple dropwise addition of a mixed solution of PVA-CuFC, PVA and iron salt into an ammonium hydroxide solution. The synthesis and chemical immobilization of the PVA-CuFC in the magnetic beads were simple, facile and achieved in one pot, and the process is scalable and convenient for the large-scale treatment of Cs-contaminated water. The resulting CuFC-MHBs showed effective Cs removal performance with a high Kd value of 66,780 mL/g and excellent structural stability without the release of CuFC for at least 1 month and could be effectively separated from water by an external magnet. Moreover, the CuFC-MHBs selectively adsorbed Cs with high Kd values in the presence of various competing ions, such as in simulated groundwater (24,500 mL/g) and seawater (8290 mL/g), and maintained their Cs absorption ability in a wide pH range from 3 to 11. The convenient fabrication method and effective removal of Cs from various aqueous media demonstrated that the CuFC-MHBs have great potential for practical application in the decontamination of Cs-contaminated water sources caused by nuclear accidents and radioactive liquid waste in various nuclear industry fields.


Assuntos
Césio/química , Ferrocianetos/química , Ferrocianetos/síntese química , Hidrogéis/química , Resíduos Radioativos/análise , Poluentes Químicos da Água/análise , Poluentes Radioativos da Água/análise , Purificação da Água/métodos , Adsorção , Monitoramento Ambiental/métodos , Cinética , Imãs/química , Álcool de Polivinil/química , Água do Mar , Água/química
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