作者机构：
[Tan, Wenfa; Ding, DX; Ding, Dexin; Yu, Huang; Hu, Nan] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.;[Yan, Qingyun; Zhang, Dandan; Yan, QY; He, Zhili; Yu, Huang; Liu, Huanping; Chen, Pubo] Sun Yat Sen Univ, Marine Synthet Ecol Res Ctr, China ASEAN Belt & Rd Joint Lab Mariculture Techn, Southern Marine Sci & Engn Guangdong Lab Zhuhai,G, Zhuhai 519082, Peoples R China.;[Liu, Shengwei] Univ Warwick, Sch Life Sci, Coventry CV4 7AL, W Midlands, England.;[Hu, Ruiwen] Lawrence Berkeley Natl Lab, Environm Genom & Syst Biol Div, Berkeley, CA 94720 USA.;[Zhou, Qiang] Jishou Univ, Coll Biol & Environm Sci, Jishou 416000, Xiangxi Tujia &, Peoples R China.
通讯机构：
[Yan, QY ] S;[Ding, DX ] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.;Sun Yat Sen Univ, Marine Synthet Ecol Res Ctr, China ASEAN Belt & Rd Joint Lab Mariculture Techn, Southern Marine Sci & Engn Guangdong Lab Zhuhai,G, Zhuhai 519082, Peoples R China.
关键词：
arsenic methylation;dissimilatory nitrate reduction to ammonium;microorganism enrichment;nitrogen fixation;phytoremediation
摘要：
Plants can recruit microorganisms to enhance soil arsenic (As) removal and nitrogen (N) turnover, but how microbial As methylation in the rhizosphere is affected by N biotransformation is not well understood. Here, we used acetylene reduction assay, arsM gene amplicon, and metagenome sequencing to evaluate the influence of N biotransformation on As methylation in the rhizosphere of Vetiveria zizanioides, a potential As hyperaccumulator. V. zizanioides was grown in mining soils (MS) and artificial As-contaminated soils (AS) over two generations in a controlled pot experiment. Results showed that the content of dimethylarsinic acid in the rhizosphere was significantly positively correlated with the rate of N fixation and the activity of nitrite reductase. The As-methylating species (e.g., Flavisolibacter and Paraflavitalea) were significantly enriched in the root-associated compartments in the second generation of MS and AS. Notably, higher abundance of genes involved in N fixation (nifD, nifK) and dissimilatory nitrate reduction to ammonium (narG/H, nirB/D/K/S) was detected in the second generation of MS than in the first generation. The metabolic pathway analysis further demonstrated that N fixing-stimulative and DNRA-stimulative As-methylating species could provide ammonium to enhance the synthesis of S-adenosyl-l-methionine, serving as methyl donors for soil As methylation. This study highlights two important N conversion-stimulative As-methylating pathways and has important implications for enhancing phytoremediation in As-contaminated soils.
通讯机构：
[Dai, ZR ] U;[Han, S ] H;Hebei Univ Engn, Coll Mat Sci & Engn, Handan Key Lab Novel Nanobiomat, Handan 056000, Peoples R China.;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Min, Hengyang 421001, Peoples R China.
摘要：
Photocatalytic removal of uranium is an efficient method for uranium removal. In this paper, a novel g-C 3 N 4 @C-PAN nanofiber membrane has been prepared by electrospinning and thermal polymerization from carbonized dicyandiamide and polyacrylonitrile fiber film, and it has been used for photocatalytic removal of U( VI ) under LED illumination. The experimental results show that the removal rate of U( VI ) by g-C 3 N 4 @C-PAN was nearly 100% in a wide concentration range of U( VI ) with great anti-interference performance. After 5 cycles, the removal rate of g-C 3 N 4 @C-PAN for uranium remains above 90%, showing excellent reusable performance. The mechanism studies show that the e − and ˙O 2 − play an important role in the photocatalytic removal of U( VI ), and they can react with U( VI ) to form (UO 2 )O 2 ·2H 2 O, thus realizing the fixation and removal of U( VI ). This work shows that the nanofiber membrane prepared by electrospinning technology has considerable application prospects for the photocatalytic treatment of uranium-containing wastewater.
摘要：
Herein, a novel composite cathode material of Ni foam supported by amidoxime cellulose microspheres (ACM@Ni) has been prepared. The removal rate of U(VI) can reach 95% within 4 h under the conditions of 298.15 K, pH = 4 and 1.2 V, which was 5 times faster than the physical adsorption. The adsorption data of U(VI) were consistent with the quasi-first-order kinetic and Freundlich isotherm model, revealing the multilayer chemisorption process of uranium on the ACM-5@Ni cathode. In addition, ACM-5@Ni electrode materials also have potential application prospects in the actual treatment of uranium containing wastewater. XRD and XPS studies show that the U(VI) adsorbed by ACM-5@Ni cathode was reduced to U(IV) in the process of uranium removal.
摘要：
During the in-situ leaching process of sandstone uranium ore deposits, the dynamic evolution of reactive transport parameters, including permeability, tortuosity, and specific surface area (SSA), plays a crucial role in solution flow and solute transport. Characterizing the evolution of these parameters is essential for understanding the leaching process. However, the heterogeneous pore structure of sandstone renders porosity alone insufficient to capture changes in these parameters. This study combines porosity and lacunarity to comprehensively characterize these parameters. For this purpose, leaching experiments were conducted on sandstone uranium ore samples, and CT imaging was performed at different leaching time points. The evolution of reactive transport parameters was analyzed by studying cubic subsamples from the images. The results indicate that both porosity and lacunarity are significant factors influencing the reactive transport parameters. However, neither parameter alone adequately characterizes their evolution. In contrast, combining them accurately characterizes the evolution of reactive transport parameters. Porosity reflects pore quantity, while lacunarity represents pore heterogeneity. Combining these measures facilitates a comprehensive understanding of the evolution of reactive transport parameters and the influence of pore microstructure on macroscopic reactive transport parameters. This research provides valuable insights for optimizing the leaching process in sandstone uranium ore deposits.
During the in-situ leaching process of sandstone uranium ore deposits, the dynamic evolution of reactive transport parameters, including permeability, tortuosity, and specific surface area (SSA), plays a crucial role in solution flow and solute transport. Characterizing the evolution of these parameters is essential for understanding the leaching process. However, the heterogeneous pore structure of sandstone renders porosity alone insufficient to capture changes in these parameters. This study combines porosity and lacunarity to comprehensively characterize these parameters. For this purpose, leaching experiments were conducted on sandstone uranium ore samples, and CT imaging was performed at different leaching time points. The evolution of reactive transport parameters was analyzed by studying cubic subsamples from the images. The results indicate that both porosity and lacunarity are significant factors influencing the reactive transport parameters. However, neither parameter alone adequately characterizes their evolution. In contrast, combining them accurately characterizes the evolution of reactive transport parameters. Porosity reflects pore quantity, while lacunarity represents pore heterogeneity. Combining these measures facilitates a comprehensive understanding of the evolution of reactive transport parameters and the influence of pore microstructure on macroscopic reactive transport parameters. This research provides valuable insights for optimizing the leaching process in sandstone uranium ore deposits.
期刊：
Separation and Purification Technology,2025年354:129241 ISSN：1383-5866
通讯作者：
Zhongran Dai
作者机构：
[Dai, Zhongran; Liang, Beichao; Chen, Lijie] Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China;[Zhang, Weilin] College of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, Hunan, China;[Gao, Yuan] School of Chemical Engineering and Technology, China University of Mining & Technology, Xuzhou, Jiangsu 221116, China;[Li, Le] Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China<&wdkj&>College of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, Hunan, China
通讯机构：
[Zhongran Dai] K;Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China
摘要：
Photocatalysis holds promise for extracting uranium from aqueous solution. Nevertheless, conventional approaches generally rely on sacrificial agents and anaerobic conditions to maintain photocatalytic efficiency, which increases costs and causes secondary pollution. Herein, we introduce the design and synthesis of an S-scheme ZnIn2S4/g-C3N4 (ZISCN) heterojunction photocatalyst for the efficient removal of uranium via in-situ generating ZnIn2S4 on g-C3N4. Photoelectric characterization and theoretical calculation indicate that ZISCN boosts the absorption of visible light and promotes the effective separation and migration of charge carriers by forming an internal electric field (IEF) at the S-scheme heterojunction interface. This configuration integrates the strong reducing electrons of g-C3N4 and the potent oxidation holes of ZnIn2S4. Consequently, the as-synthesized ZISCN can efficiently remove uranium under an air atmosphere without the need for sacrificial agents and anaerobic conditions. The achieved U(VI) removal rate of 94.8 % surpasses that of ZnIn2S4 and g-C3N4 individually. Moreover, the photocatalytic extraction of U(VI) by ZISCN photocatalyst demonstrated excellent stability and anti-interference performance. After five cycles, the U(VI) removal rate remained above 85 %. Mechanism studies reveal that when electrons are generated by light in the ZISCN systems, they can reduce O2, leading to the formation of reactive species ·O2/H2O2. These species subsequently interact with U(VI), resulting in the precipitation of (UO2)O2·2H2O on the surface of ZISCN. This research provides valuable insights for the design of heterojunction photocatalysts for efficient, sacrificial agent-free uranium removal in ambient air environments.
期刊：
Science of The Total Environment,2025年958:177896 ISSN：0048-9697
通讯作者：
Dexin Ding
作者机构：
[Li, Guangyue; Li, Aishu; Yi, Haitao; Wang, Yongdong; Wang, Haonan] Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Heng Yang 421001, Hunan, PR China;[Ding, Dexin] Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Heng Yang 421001, Hunan, PR China. Electronic address: Ddingusc@163.com
通讯机构：
[Dexin Ding] K;Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Heng Yang 421001, Hunan, PR China
关键词：
Acidic groundwater;In site bioremediation;Nitrate;Tumebacillus;Uranium
摘要：
In-situ leaching (ISL) is the predominant technology used in uranium mining currently, although it leads to significant environmental challenges. Nitrates, a key component in leaching agents, not only pose a threat to human health but also impede the bioreduction of U(VI) in uranium-contaminated water. In this study, the nitrate reducing bacterial (NRB) communities adapted to acidic uranium-contaminated groundwater from a site in Northwest China were gained by an enrichment micro-model. The effects of the NRB communities on the groundwater parameters and microbial diversity were evaluated using the groundwater-core column leaching system during the in-situ bioremediation of nitrate. The enrichment experiments revealed that NRB communities adapted to acidic uranium-contaminated groundwater were successfully enriched, of which Tumebacillus was the main functional bacterium. The column leaching experiment results showed that adding NRB communities successfully reduced nitrate levels from 100.91 mg/L to 0.7 mg/L in just 8 days, improved groundwater acidity and redox conditions. Additionally, the metagenomic analysis showed that introducing NRB communities increased biomass and indigenous NRB, but decreased microbial diversity. The KEGG enrichment analysis suggested that butanoate metabolism and valine, leucine and isoleucine degradation were promoted by adding enriched NRB communities. This research lays the groundwork for nitrate removal from contaminated groundwater in areas affected by ISL in uranium mines, setting the stage for future in situ bioremediation of U(VI).
In-situ leaching (ISL) is the predominant technology used in uranium mining currently, although it leads to significant environmental challenges. Nitrates, a key component in leaching agents, not only pose a threat to human health but also impede the bioreduction of U(VI) in uranium-contaminated water. In this study, the nitrate reducing bacterial (NRB) communities adapted to acidic uranium-contaminated groundwater from a site in Northwest China were gained by an enrichment micro-model. The effects of the NRB communities on the groundwater parameters and microbial diversity were evaluated using the groundwater-core column leaching system during the in-situ bioremediation of nitrate. The enrichment experiments revealed that NRB communities adapted to acidic uranium-contaminated groundwater were successfully enriched, of which Tumebacillus was the main functional bacterium. The column leaching experiment results showed that adding NRB communities successfully reduced nitrate levels from 100.91 mg/L to 0.7 mg/L in just 8 days, improved groundwater acidity and redox conditions. Additionally, the metagenomic analysis showed that introducing NRB communities increased biomass and indigenous NRB, but decreased microbial diversity. The KEGG enrichment analysis suggested that butanoate metabolism and valine, leucine and isoleucine degradation were promoted by adding enriched NRB communities. This research lays the groundwork for nitrate removal from contaminated groundwater in areas affected by ISL in uranium mines, setting the stage for future in situ bioremediation of U(VI).
作者：
Haiying Fu*;Meng Lian;Zhiman Yang;Dexin Ding;Guicheng He
期刊：
Nuclear Engineering and Technology,2025年:103435 ISSN：1738-5733
通讯作者：
Haiying Fu
作者机构：
Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, PR China;[Meng Lian; Zhiman Yang; Guicheng He] School of Resource Environment and Safety Engineering, University of South China, Hengyang, 421001, PR China;[Haiying Fu; Dexin Ding] Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, PR China<&wdkj&>School of Resource Environment and Safety Engineering, University of South China, Hengyang, 421001, PR China
通讯机构：
[Haiying Fu] K;Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, PR China<&wdkj&>School of Resource Environment and Safety Engineering, University of South China, Hengyang, 421001, PR China
摘要：
Based upon the lattice Boltzmann method, the current paper developed a visual simulation method for the evolution of porous structure during the acid leaching process. The reliability of the model in simulating fluid flow, solute diffusion, calcite dissolution, and gypsum precipitation was validated using four benchmark tests. The model was then used to investigate the effects of calcite distribution, sulfuric acid concentration, and porous structure on reactive transport processes. Results demonstrated that simulated values closely aligned with theoretical solutions or experimental data, confirming the model's validity. Applications showed that, when calcite was distributed near the injection end, precipitation near the inlet led to a rapid permeability decline. Higher sulfuric acid concentrations caused faster permeability reduction. The porous structure distribution significantly impacted permeability evolution, especially when blockades in main flow paths greatly affected permeability and reactive transport processes. Furthermore, when pore and mineral distributions were homogeneous, permeability evolution with porosity followed a power-law relationship, but this relationship did not hold when distributions were heterogeneous. Due to the difficulty in quantifying mineral and pore heterogeneities, combining porous structure and mineral distribution images with visual simulations created a practical approach for studying dynamic reactive transport in in-situ acid leaching of sandstone uranium deposits.
Based upon the lattice Boltzmann method, the current paper developed a visual simulation method for the evolution of porous structure during the acid leaching process. The reliability of the model in simulating fluid flow, solute diffusion, calcite dissolution, and gypsum precipitation was validated using four benchmark tests. The model was then used to investigate the effects of calcite distribution, sulfuric acid concentration, and porous structure on reactive transport processes. Results demonstrated that simulated values closely aligned with theoretical solutions or experimental data, confirming the model's validity. Applications showed that, when calcite was distributed near the injection end, precipitation near the inlet led to a rapid permeability decline. Higher sulfuric acid concentrations caused faster permeability reduction. The porous structure distribution significantly impacted permeability evolution, especially when blockades in main flow paths greatly affected permeability and reactive transport processes. Furthermore, when pore and mineral distributions were homogeneous, permeability evolution with porosity followed a power-law relationship, but this relationship did not hold when distributions were heterogeneous. Due to the difficulty in quantifying mineral and pore heterogeneities, combining porous structure and mineral distribution images with visual simulations created a practical approach for studying dynamic reactive transport in in-situ acid leaching of sandstone uranium deposits.
摘要：
Mercury (Hg) pollution poses a critical threat to human health and the environment, necessitating urgent control measures. This study introduces a novel modification method for the common zero-valent iron-carbon (ZVI-AC) galvanic cells using a two-step process, nonthermal (NTP) irradiation followed by targeted functionalization, aiming to enhance Hg adsorption potential by adjusting the physicochemical properties of the cells. The NTP irradiated functionalized adsorbent demonstrated superior Hg adsorption performance across various concentrations and pH variations. Multichannel adsorption mechanisms were confirmed by fitting a total of 22 different adsorption isotherm models, indicating the coexistence of monolayer and multilayer adsorption processes. The NTP irradiation modifies the ZVI and AC, inducing nitrogen and oxygen doping on carbon-based surfaces and oxidizing ZVI to Fe(II)-Fe(III) species. The deepened oxidation of Fe in NTP-Fe-C, coupled with Hg 2+ reduction to elemental Hg by raw Fe, contributed to Hg removal. NTP irradiation facilitated electron transfer between Fe and Hg, promoting oxidation of Fe and reduction of Hg 2+ cations. The emergence of diverse Hg species further supported the multichannel adsorption/removal mechanism achieved by NTP-irradiated cells. This method offers a promising solution to Hg pollution and expands the application of the traditional iron-carbon galvanic cells in treating hazardous heavy metal wastes.
Mercury (Hg) pollution poses a critical threat to human health and the environment, necessitating urgent control measures. This study introduces a novel modification method for the common zero-valent iron-carbon (ZVI-AC) galvanic cells using a two-step process, nonthermal (NTP) irradiation followed by targeted functionalization, aiming to enhance Hg adsorption potential by adjusting the physicochemical properties of the cells. The NTP irradiated functionalized adsorbent demonstrated superior Hg adsorption performance across various concentrations and pH variations. Multichannel adsorption mechanisms were confirmed by fitting a total of 22 different adsorption isotherm models, indicating the coexistence of monolayer and multilayer adsorption processes. The NTP irradiation modifies the ZVI and AC, inducing nitrogen and oxygen doping on carbon-based surfaces and oxidizing ZVI to Fe(II)-Fe(III) species. The deepened oxidation of Fe in NTP-Fe-C, coupled with Hg 2+ reduction to elemental Hg by raw Fe, contributed to Hg removal. NTP irradiation facilitated electron transfer between Fe and Hg, promoting oxidation of Fe and reduction of Hg 2+ cations. The emergence of diverse Hg species further supported the multichannel adsorption/removal mechanism achieved by NTP-irradiated cells. This method offers a promising solution to Hg pollution and expands the application of the traditional iron-carbon galvanic cells in treating hazardous heavy metal wastes.
期刊：
Journal of Hazardous Materials,2025年490:137863 ISSN：0304-3894
通讯作者：
Ye, Yongjun
作者机构：
[Ye, Yongjun; Wang, Haofeng] National Joint Engineering Research Center for Airborne Pollutants Control and Radiological Protection in Building Environment, University of South China, Hengyang, Hunan 421001, China;[Ye, Yongjun] Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China;[Ye, Yongjun] School of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, China. Electronic address: yongjunye@163.com;[Yao, Xuanli; Luo, Liling] School of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, China
通讯机构：
[Yongjun Ye] N;National Joint Engineering Research Center for Airborne Pollutants Control and Radiological Protection in Building Environment, University of South China, Hengyang, Hunan 421001, China<&wdkj&>Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China<&wdkj&>School of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, China
摘要：
In radon pollution control, materials with radon adsorbing characteristics will significantly affect the migration and release of radon. In this paper, radon adsorbing medium (activated carbon particles) is proposed to be added to the building foundation granular filling layer as a radon adsorbing layer to alleviate indoor radon pollution. Radon exhalation rate is an important physical quantity used to evaluate the radon exhalation capacity of materials. This study compared the measurement results of radon exhalation rate on the radon adsorbing media surface by the traditional Closed-loop Method (CLM) and the Activated Carbon Purification Closed-loop Method (ACPCM) through experiments. The results show that the surface radon exhalation rate decrease rapidly due to the back diffusion effect of CLM, which seriously affects the measurement results. ACPCM can avoid the interference of back diffusion effect on the adsorption amount of radon adsorbing medium, obtaining reliable measurement results. In addition, the migration process of radon in the gas-solid medium and its interface during the measurement was simulated by computational fluid dynamics (CFD), and the measurement mechanism of the two methods was revealed. The research results can provide reference for the determination of radon exhalation rate on the radon adsorbing medium surface.
In radon pollution control, materials with radon adsorbing characteristics will significantly affect the migration and release of radon. In this paper, radon adsorbing medium (activated carbon particles) is proposed to be added to the building foundation granular filling layer as a radon adsorbing layer to alleviate indoor radon pollution. Radon exhalation rate is an important physical quantity used to evaluate the radon exhalation capacity of materials. This study compared the measurement results of radon exhalation rate on the radon adsorbing media surface by the traditional Closed-loop Method (CLM) and the Activated Carbon Purification Closed-loop Method (ACPCM) through experiments. The results show that the surface radon exhalation rate decrease rapidly due to the back diffusion effect of CLM, which seriously affects the measurement results. ACPCM can avoid the interference of back diffusion effect on the adsorption amount of radon adsorbing medium, obtaining reliable measurement results. In addition, the migration process of radon in the gas-solid medium and its interface during the measurement was simulated by computational fluid dynamics (CFD), and the measurement mechanism of the two methods was revealed. The research results can provide reference for the determination of radon exhalation rate on the radon adsorbing medium surface.
摘要：
The efficient extraction of uranium from acid mining wastewater remains a significant challenge. In this study, a novel phospho-enriched polyamidoxime/alginate (PA/PAO/SA) gel beads was fabricated through a one-pot self-assembly method with calcium ions for crosslinking and used for efficient extraction of U(VI). Drawing on abundant functional groups, the PA/PAO/SA gel beads exhibited remarkable uranium extraction performance in acidic uranium-containing wastewater within the pH range of 2.5–5.5, and the removal rate of a 20 mg/L uranium-containing solution was nearly 100 % and it showed great selectivity ( K d = 1.9 L/g) at pH 4.0. The data of U(VI) adsorption fit well with the Langmuir isothermal adsorption and the quasi-second-order kinetic model, which indicates the adsorption behavior of PA/PAO/SA gel beads for U(VI) pertains to single layer chemisorption. Notably, PA/PAO/SA gel beads display excellent mechanical properties and stability, and the removal rate of U(VI) by PA/PAO/SA gel beads only a 3.86 % decrease after 10 consecutive adsorption–desorption cycles. The results of dynamic fixed-bed column experiment showed that the PA/PAO/SA gel beads can reduce the U(VI) concentration of the actual acidic uranium-containing wastewater with a volume of 600 bed volumes (BV) to below the national discharge standard (GB 23727–2020), and the adsorbed uranium can be completely desorbed with only 60 BV of eluent. Mechanism studies conducted through characterization and DFT calculations unveil that the synergistic effects of electrostatic, coordination and ion exchange endow PA/PAO/SA gel beads with excellent selective adsorption properties for U(VI). This study provides a promising adsorption material and strategy for the efficient extraction of uranium from acidic nuclear wastewater.
The efficient extraction of uranium from acid mining wastewater remains a significant challenge. In this study, a novel phospho-enriched polyamidoxime/alginate (PA/PAO/SA) gel beads was fabricated through a one-pot self-assembly method with calcium ions for crosslinking and used for efficient extraction of U(VI). Drawing on abundant functional groups, the PA/PAO/SA gel beads exhibited remarkable uranium extraction performance in acidic uranium-containing wastewater within the pH range of 2.5–5.5, and the removal rate of a 20 mg/L uranium-containing solution was nearly 100 % and it showed great selectivity ( K d = 1.9 L/g) at pH 4.0. The data of U(VI) adsorption fit well with the Langmuir isothermal adsorption and the quasi-second-order kinetic model, which indicates the adsorption behavior of PA/PAO/SA gel beads for U(VI) pertains to single layer chemisorption. Notably, PA/PAO/SA gel beads display excellent mechanical properties and stability, and the removal rate of U(VI) by PA/PAO/SA gel beads only a 3.86 % decrease after 10 consecutive adsorption–desorption cycles. The results of dynamic fixed-bed column experiment showed that the PA/PAO/SA gel beads can reduce the U(VI) concentration of the actual acidic uranium-containing wastewater with a volume of 600 bed volumes (BV) to below the national discharge standard (GB 23727–2020), and the adsorbed uranium can be completely desorbed with only 60 BV of eluent. Mechanism studies conducted through characterization and DFT calculations unveil that the synergistic effects of electrostatic, coordination and ion exchange endow PA/PAO/SA gel beads with excellent selective adsorption properties for U(VI). This study provides a promising adsorption material and strategy for the efficient extraction of uranium from acidic nuclear wastewater.
摘要：
The average radon exhalation rate of the building wall surface is a key factor affecting indoor radon concentration, and its accurate measurement is of great significance for the evaluation and design of radon protection for walls. The main layer of the masonry walls is composed of bricks and bonded cement mortar. Due to the possible differences in radon exhalation rates from brick surfaces and cement mortar joints. General methods for measuring radon exhalation rate of the wall (such as the closed-loop method, the opened-loop method and the local static collection method) all involve the use of radon collection hoods. However, the measurement results of radon exhalation rate are significantly affected by the position and size of the radon collection hood covering the wall surface. Therefore, the Computational Fluid Dynamics (CFD) method was used to study the radon exhalation rules on the surface of masonry wall under diffusion and seepage-diffusion conditions, respectively. The simulation results show that the radon exhalation rates on the brick surfaces and cement mortar joints of masonry walls are different, and a representative elementary surface (RES) should be selected when accurately measuring the radon exhalation rate of the wall surface. It is worth noting that the shape of the RES is not restricted, and the representative surface for measuring radon exhalation rate is not unique; it can be an integer multiple surface of RES area. Furthermore, experiments have confirmed the accuracy and effectiveness of the determined RES. The proposed RES achieves accurate measurement of the average radon exhalation rate of walls by integrating the radon exhalation rates at the joints between bricks and cement mortar.
The average radon exhalation rate of the building wall surface is a key factor affecting indoor radon concentration, and its accurate measurement is of great significance for the evaluation and design of radon protection for walls. The main layer of the masonry walls is composed of bricks and bonded cement mortar. Due to the possible differences in radon exhalation rates from brick surfaces and cement mortar joints. General methods for measuring radon exhalation rate of the wall (such as the closed-loop method, the opened-loop method and the local static collection method) all involve the use of radon collection hoods. However, the measurement results of radon exhalation rate are significantly affected by the position and size of the radon collection hood covering the wall surface. Therefore, the Computational Fluid Dynamics (CFD) method was used to study the radon exhalation rules on the surface of masonry wall under diffusion and seepage-diffusion conditions, respectively. The simulation results show that the radon exhalation rates on the brick surfaces and cement mortar joints of masonry walls are different, and a representative elementary surface (RES) should be selected when accurately measuring the radon exhalation rate of the wall surface. It is worth noting that the shape of the RES is not restricted, and the representative surface for measuring radon exhalation rate is not unique; it can be an integer multiple surface of RES area. Furthermore, experiments have confirmed the accuracy and effectiveness of the determined RES. The proposed RES achieves accurate measurement of the average radon exhalation rate of walls by integrating the radon exhalation rates at the joints between bricks and cement mortar.
期刊：
Journal of Hazardous Materials,2025年490:137860 ISSN：0304-3894
通讯作者：
Ding, Yang
作者机构：
[Huang, Xixian; Dou, Ye; Yang, Bing] School of Resource & Environment and Safety Engineering, University of South China, Hengyang, Hunan 421001, China;Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China;[Ding, Yang] School of Resource & Environment and Safety Engineering, University of South China, Hengyang, Hunan 421001, China<&wdkj&>Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China
通讯机构：
[Yang Ding] S;School of Resource & Environment and Safety Engineering, University of South China, Hengyang, Hunan 421001, China<&wdkj&>Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China
摘要：
Both manganese dioxide (MnO₂) and dissolved organic matter (DOM) exert a significant influence on the chemical species of uranium in the contaminated soils, yet the impacts of the interactions between MnO 2 and DOM, particularly in the presence of iron oxyhydroxides, on the environmental behaviors of uranium have not been elucidated. In this study, the dynamic behaviors of uranium were investigated during the reactions of DOM with δ-MnO 2 in the presence of goethite at different pH values, by employing a combination of kinetic experiments, spectrophotometric titration, X-ray photoelectron spectroscopy, and electrochemical analysis. Our results indicated that the presence of DOM decreased uranium adsorption on MnO 2 and promoted the release of uranium bound to DOM and MnO 2 through the oxidation of DOM and the reduction of MnO 2 , respectively. Goethite increased uranium adsorption on its surface and hindered the direct oxidation of DOM by MnO 2 , but the indirect oxidation of goethite-adsorbed DOM by MnO 2 provided an additional route for uranium release. We found that uranium concentration in solution was positively correlated with Mn(II) concentration at pH 4.5, whereas it was positively correlated with the concentration of dissolved organic carbon and negatively correlated with the aromaticity and molecular weight of DOM at pH 6.5. Above results highlighted the significance of the redox process between MnO 2 and DOM in regulating the dynamic behaviors of uranium, which contributed to a better understanding of the sequestration and stability of uranium in the contaminated soils around the uranium tailings ponds.
Both manganese dioxide (MnO₂) and dissolved organic matter (DOM) exert a significant influence on the chemical species of uranium in the contaminated soils, yet the impacts of the interactions between MnO 2 and DOM, particularly in the presence of iron oxyhydroxides, on the environmental behaviors of uranium have not been elucidated. In this study, the dynamic behaviors of uranium were investigated during the reactions of DOM with δ-MnO 2 in the presence of goethite at different pH values, by employing a combination of kinetic experiments, spectrophotometric titration, X-ray photoelectron spectroscopy, and electrochemical analysis. Our results indicated that the presence of DOM decreased uranium adsorption on MnO 2 and promoted the release of uranium bound to DOM and MnO 2 through the oxidation of DOM and the reduction of MnO 2 , respectively. Goethite increased uranium adsorption on its surface and hindered the direct oxidation of DOM by MnO 2 , but the indirect oxidation of goethite-adsorbed DOM by MnO 2 provided an additional route for uranium release. We found that uranium concentration in solution was positively correlated with Mn(II) concentration at pH 4.5, whereas it was positively correlated with the concentration of dissolved organic carbon and negatively correlated with the aromaticity and molecular weight of DOM at pH 6.5. Above results highlighted the significance of the redox process between MnO 2 and DOM in regulating the dynamic behaviors of uranium, which contributed to a better understanding of the sequestration and stability of uranium in the contaminated soils around the uranium tailings ponds.
摘要：
The abiotic oxidation of divalent manganese (Mn(II)) and the formation of Mn oxides are important geochemical processes, which control the mobility and availability of Mn as well as element cycling and pollutant behavior in soils. It was found that iron (oxyhydr)oxides can catalyze Mn(II) oxidation, but the effects of the coexisting dissolved organic matter (DOM) molecules on the catalysis of different iron (oxyhydr)oxides for Mn(II) oxidation are poorly understood. Herein, we investigated Mn(II) oxidation under the impacts of the interactions between iron (oxyhydr)oxides (i.e., ferrihydrite, goethite and hematite) and DOM molecules. Simultaneously, we elucidated the variations of DOM composition and properties. Our results indicated that the catalysis of iron (oxyhydr)oxides for Mn(II) oxidation was significantly inhibited by DOM. Moreover, DOM had less inhibiting effect on the catalysis of ferrihydrite for Mn(II) oxidation and the formation of Mn oxides (e.g., hausmannite and buserite) relative to goethite and hematite, which was partially because of the higher electron transfer capacities of ferrihydrite. Meanwhile, DOM molecules with high nominal oxidation state of carbon (NOSC), molecular weight, unsaturation and aromaticity were selectively adsorbed and oxidized by Mn oxides, including the oxygenated phenols and polyphenols. The newly formed molecules mainly belonged to phenols depleted of oxygen and aliphatics. Furthermore, NOSC was a key molecular characteristic for controlling DOM composition during DOM adsorption and oxidation by Mn oxides when iron minerals were present. Overall, our research contributes to understanding Mn(II) oxidation mechanisms under heterogeneous systems and behaviors of DOM molecules in the environment.
The abiotic oxidation of divalent manganese (Mn(II)) and the formation of Mn oxides are important geochemical processes, which control the mobility and availability of Mn as well as element cycling and pollutant behavior in soils. It was found that iron (oxyhydr)oxides can catalyze Mn(II) oxidation, but the effects of the coexisting dissolved organic matter (DOM) molecules on the catalysis of different iron (oxyhydr)oxides for Mn(II) oxidation are poorly understood. Herein, we investigated Mn(II) oxidation under the impacts of the interactions between iron (oxyhydr)oxides (i.e., ferrihydrite, goethite and hematite) and DOM molecules. Simultaneously, we elucidated the variations of DOM composition and properties. Our results indicated that the catalysis of iron (oxyhydr)oxides for Mn(II) oxidation was significantly inhibited by DOM. Moreover, DOM had less inhibiting effect on the catalysis of ferrihydrite for Mn(II) oxidation and the formation of Mn oxides (e.g., hausmannite and buserite) relative to goethite and hematite, which was partially because of the higher electron transfer capacities of ferrihydrite. Meanwhile, DOM molecules with high nominal oxidation state of carbon (NOSC), molecular weight, unsaturation and aromaticity were selectively adsorbed and oxidized by Mn oxides, including the oxygenated phenols and polyphenols. The newly formed molecules mainly belonged to phenols depleted of oxygen and aliphatics. Furthermore, NOSC was a key molecular characteristic for controlling DOM composition during DOM adsorption and oxidation by Mn oxides when iron minerals were present. Overall, our research contributes to understanding Mn(II) oxidation mechanisms under heterogeneous systems and behaviors of DOM molecules in the environment.
摘要：
Organic matter retained by reactive minerals constitutes an essential mechanism for long-term storage of carbon in soil, a process that is governed by climate factors. However, how the reactive mineral-associated organic matter affects the composition of soil dissolved organic matter (DOM) across a broad range of climates remains unclear. In this study, the contents of reactive minerals and their associated organic matter were determined by the chemical extraction method. Moreover, the effects of organic matter retained by reactive minerals on soil DOM composition were investigated at molecular level across a wide environmental gradient, by employing Fourier transform ion cyclotron resonance mass spectrometry, solid-state 13C nuclear magnetic resonance and statistical analyses. The results of FT-ICR-MS and correlation analyses indicated that the relative abundances of carbohydrates and proteins/amino sugars decreased, while the relative abundance of condensed aromatics increased with the increase of the content of organic matter retained by reactive minerals per unit mass (i.e., (OC)RN) in soils. We highlighted that the adsorption and dissolution processes of DOM molecules, especially aromatic molecules, on reactive minerals played crucial roles in regulating the molecular composition of DOM in soil solution. Furthermore, (OC)RN was controlled by climate-driven chemical weathering (e.g., precipitation). Our results imply that (OC)RN is a key variable for regulating soil DOM composition under the impacts of climates, and can be used in developing prediction models for carbon cycling.
Organic matter retained by reactive minerals constitutes an essential mechanism for long-term storage of carbon in soil, a process that is governed by climate factors. However, how the reactive mineral-associated organic matter affects the composition of soil dissolved organic matter (DOM) across a broad range of climates remains unclear. In this study, the contents of reactive minerals and their associated organic matter were determined by the chemical extraction method. Moreover, the effects of organic matter retained by reactive minerals on soil DOM composition were investigated at molecular level across a wide environmental gradient, by employing Fourier transform ion cyclotron resonance mass spectrometry, solid-state 13C nuclear magnetic resonance and statistical analyses. The results of FT-ICR-MS and correlation analyses indicated that the relative abundances of carbohydrates and proteins/amino sugars decreased, while the relative abundance of condensed aromatics increased with the increase of the content of organic matter retained by reactive minerals per unit mass (i.e., (OC)RN) in soils. We highlighted that the adsorption and dissolution processes of DOM molecules, especially aromatic molecules, on reactive minerals played crucial roles in regulating the molecular composition of DOM in soil solution. Furthermore, (OC)RN was controlled by climate-driven chemical weathering (e.g., precipitation). Our results imply that (OC)RN is a key variable for regulating soil DOM composition under the impacts of climates, and can be used in developing prediction models for carbon cycling.
摘要：
Uranium contamination is a key issue in the sustainable development of nuclear energy. In this study, a cellulose/sericite hybrid aerogel with a layer-stacked network structure (MCC/AS-P) was prepared for uranium-contaminated wastewater treatment. Systematic characterization and multiple-batch static adsorption experiments were conducted to analyze the aerogel’s preparation, adsorption, and desorption. The kinetics demonstrated a noticeable transition between mass transfer diffusion control and mass transfer control, approaching adsorption equilibrium within 8 min and 180 min, respectively, wherein polymer layers led to a more stable adsorption process. Adsorption isotherm and thermodynamic studies established that the theoretical adsorption capacity of MCC/AS-P for U(VI) at T = 298 K could reach 374.5 mg·g−1. The adsorption behavior was endothermic and spontaneous, and the DFT calculations demonstrated that the adsorption energy of MCC/AS for UO22+ was − 506.5 kcal/mol. Temperature, U(VI) concentration, and desorption can all lead to a transition of the dominant mechanism between chemisorption and physisorption. After six swelling–deswelling adsorption cycles, the adsorption efficiency remained above 80%, and the structure remained intact. Furthermore, the excellent performance in terms of interference resistance and chemical stability offers potential for practical application.
Uranium contamination is a key issue in the sustainable development of nuclear energy. In this study, a cellulose/sericite hybrid aerogel with a layer-stacked network structure (MCC/AS-P) was prepared for uranium-contaminated wastewater treatment. Systematic characterization and multiple-batch static adsorption experiments were conducted to analyze the aerogel’s preparation, adsorption, and desorption. The kinetics demonstrated a noticeable transition between mass transfer diffusion control and mass transfer control, approaching adsorption equilibrium within 8 min and 180 min, respectively, wherein polymer layers led to a more stable adsorption process. Adsorption isotherm and thermodynamic studies established that the theoretical adsorption capacity of MCC/AS-P for U(VI) at T = 298 K could reach 374.5 mg·g−1. The adsorption behavior was endothermic and spontaneous, and the DFT calculations demonstrated that the adsorption energy of MCC/AS for UO22+ was − 506.5 kcal/mol. Temperature, U(VI) concentration, and desorption can all lead to a transition of the dominant mechanism between chemisorption and physisorption. After six swelling–deswelling adsorption cycles, the adsorption efficiency remained above 80%, and the structure remained intact. Furthermore, the excellent performance in terms of interference resistance and chemical stability offers potential for practical application.
摘要：
Phosphate-solubilizing bacteria (PSB) are important but often overlooked regulators of uranium (U) cycling in soil. However, the impact of PSB on uranate fixation coupled with the decomposition of recalcitrant phosphorus (P) in mining land remains poorly understood. Here, we combined gene amplicon sequencing, metagenome and metatranscriptome sequencing analysis and strain isolation to explore the effects of PSB on the stabilization of uranate and P availability in U mining areas. We found that the content of available phosphorus (AP), carbonate-U and Fe-Mn-U oxides in tailings was significantly (P < 0.05) higher than their adjacent soils. Also, organic phosphate mineralizing (PhoD) bacteria (e.g., Streptomyces) and inorganic phosphate solubilizing (gcd) bacteria (e.g., Rhodococcus) were enriched in tailings and soils, but only organic phosphate mineralizing-bacteria substantially contributed to the AP. Notably, most genes involved in organophosphorus mineralization and uranate resistance were widely present in tailings rather than soil. Comparative genomics analyses supported that organophosphorus mineralizing-Streptomyces species could increase soil AP content and immobilize U(VI) through organophosphorus mineralization (e.g., PhoD, ugpBAEC) and U resistance related genes (e.g., petA). We further demonstrated that the isolated Streptomyces sp. PSBY1 could enhance the U(VI) immobilization mediated by the NADH-dependent ubiquinol-cytochrome c reductase (petA) through decomposing organophosphorous compounds. This study advances our understanding of the roles of PSB in regulating the fixation of uranate and P availability in U tailings.
摘要：
Uranium mining operations produce large volumes of acidic uranium mining wastewater, necessitating the development of environmentally friendly and recyclable materials for efficient uranium removal and recovery. The current study successfully produced hydroxyapatite (HAP-L) and magnetic phosphate composites (CaFeP-1, CaFeP-2, and FePO4) through a combination of mixing, ultrasonication, hydrothermal precipitation, and calcination methods. The research explores the influence of various parameters such as pH, solid-liquid ratio, contact time, initial uranium concentration, co-existing ions, and recyclability on the uranium removal efficiency of these materials. The findings indicate exceptional uranium adsorption capacities, with CaFeP-1 exhibiting the highest capacity among the materials, especially in acidic environments. Moreover, CaFeP-1 displays strong resistance to interference from other ions and can be recycled multiple times while maintaining high removal rates. Treatment of acidic uranium mining wastewater by CaFeP-1 results in pH adjustment and the reduction of uranium and other ion concentrations, making it a promising solution for comprehensive remediation of acidic uranium mining wastewater. The U(VI) removal mechanism by CaFeP-1 was validated through XRD, FT-IR, and XPS results. The U(VI) removal was attributed to processes such as dissolution-precipitation, surface complexation, and ion exchange. The formation of sodium uranyl phosphate hydrate was identified as a new product following U(VI) abatement by CaFeP-1. In summary, CaFeP-1 shows great potential for the effective treatment of acidic uranium mining wastewater.
