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.
通讯机构：
[Xixian Huang] S;[Dexin Ding] K;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<&wdkj&>School of Resource & Environment and Safety Engineering, University of South China, Hengyang, Hunan 421001, China
摘要：
Amorphous ferrihydrite (Fh) is abundant in aquatic environments and sediments, and often coprecipitates with dissolved organic matter (DOM) to form mineral-organic aggregates. The Fe(II)-catalyzed transformation of Fh to crystalline Fe (oxyhydr)oxides (e.g., goethite) can result in the changes of uranium (U) species, but the effects of DOM molecules on the sequestration and stability of U during Fe (oxyhydr)oxides transformation are poorly understood. In this study, the associations of DOM molecules with U during the coprecipitation of DOM with Fh were evaluated, and the effects of DOM molecules on the kinetics of U release during Fe (oxyhydr)oxides transformation were investigated using a combination of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), X-ray photoelectron spectroscopy (XPS), and kinetic experiments. FT-ICR-MS results indicated that, in addition to phenolic and polyphenolic compounds with higher O/C ratios, portions of phenolic compounds with lower O/C ratios and aliphatic compounds were also contributed to UO(2)(2+) binding when Fh coprecipitated with DOM. In comparison, phenolic and polyphenolic compounds with higher O/C ratios and condensed aromatics were preferentially retained on Fe (oxyhydr)oxides during the transformation. XPS results further suggested that the coprecipitated DOM molecules facilitated the reduction of U(VI) to U(IV) during the transformation, possibly through providing electrons or acting as electron shuttles. The kinetic experiment results indicated that the transformation processes accelerated U release from Fe (oxyhydr)oxides, but the coprecipitated DOM molecules slowed down U release. Our results contribute to understanding the behaviors of U and predicting the sequestration of U in the environment.
作者机构：
[Ding, Dexin; Zhang, Hui; Sheng, Liangbing; Ma, Jianhong] Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China;[Sheng, Liangbing] Hunan Engineering Research Center for Monitoring and Treatment of Heavy Metal Pollution in the Upper Reaches of Xiangjiang River, Hengyang Normal University, Hengyang 421001, China;[Sheng, Liangbing] Hunan Province Key Laboratory of Green Development Technology for Extremely Low Grade Uranium Resources, Hengyang 421001, China;[Zhang, Hui; Ma, Jianhong] Hunan Province Key Laboratory of Green Development Technology for Extremely Low Grade Uranium Resources, Hengyang 421001, China;[Ding, Dexin] Hunan Province Key Laboratory of Green Development Technology for Extremely Low Grade Uranium Resources, Hengyang 421001, China. Electronic address: zh2015yl@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, Hengyang 421001, China<&wdkj&>Hunan Province Key Laboratory of Green Development Technology for Extremely Low Grade Uranium Resources, Hengyang 421001, China
关键词：
Acid in situ leach uranium mining;Slowly releasing phosphate;Uranium-contaminated groundwater
摘要：
Acid in-situ leach uranium mining significantly alters the geochemistry of the ore zone, and leaves uranium, residual acid, as well as other potential contaminants in groundwater, which bring harm to human health and ecological environment. Many investigators have been trying to propose remediation strategies for the uranium-contaminated groundwater. Phosphate is an effective immobilization reagent of uranium in the groundwater. However, direct injection of phosphate tends to quickly form precipitates, resulting in fast blockage of the seepage passages in the ore zone around the injection holes and hindering its diffusion. In this paper, HAP@SiO(2)-600, HAP@SiO(2)-600@25SA, and HAP@SiO(2)-600@75SA with core-shell structures were prepared. Their slow-release of phosphate, the effects of pH, contact time, initial uranium concentration, and coexisting ions on their removal rate and efficiency of uranium, and their function of remediating uranium-contaminated groundwater were investigated. It was found that the increase of SA content in the outer layer of HAP@SiO(2)-600@25SA and HAP@SiO(2)-600@75SA resulted in the slow release rate of phosphate, decreasing the removal rate of uranium. The adsorption capacities of HAP@SiO(2)-600, HAP@SiO(2)-600@25SA, and HAP@SiO(2)-600@75SA from the aqueous solution at pH=3.0 and 303K were up to 582.6, 558.5, and 507.3mgg(-1), respectively. In addition, the materials showed excellent uranium removal performance in experiments where multiple ions coexisted. For actual acidic uranium-contaminated groundwater, HAP@SiO(2)-600, HAP@SiO(2)-600@25SA, and HAP@SiO(2)-600@75SA effectively increased the pH from 2.75 to 4.40, 3.87, and 3.72, respectively, and decreased the uranium concentration from 5.12 to 0.0062, 0.0065, and 0.0058mgL(-1), respectively. The FT-IR, XRD, TEM and XPS characterizations were performed to further clarify the uranium removal mechanism, and it was found that the elimination of U(VI) was ascribed to dissolution-precipitation, adsorption and ion exchange. The results show that the core-shell composite material capable of slowly releasing phosphate is effective in remediating uranium-contaminated groundwater.
期刊：
Environmental Science: Water Research & Technology,2023年9(5):1480-1490 ISSN：2053-1400
通讯作者：
Ding, Dexin(dingdxzzz@163.com)
作者机构：
[Ding, Dexin; Zhang, Hui; Hu, Nan; Ding, Yang; Liu, Yalan] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Min, Hengyang 421001, Peoples R China.;[Ding, Dexin; Zhang, Hui; Hu, Nan; Ding, Yang; Liu, Yalan] Hunan Prov Key Lab Green Dev Technol Extremely Low, Hengyang 421001, Peoples R China.
通讯机构：
[Dexin Ding] K;Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China<&wdkj&>Hunan Province Key Laboratory of Green Development Technology for Extremely Low Grade Uranium Resources, Hengyang 421001, China
通讯机构：
[Ding, Y ] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Min, Hengyang 421001, Peoples R China.;Univ South China, Sch Resource & Environm & Safety Engn, Hengyang 421001, Hunan, Peoples R China.
关键词：
Uranium;Immobilization;Hydrogen peroxide;Phosphate;Amorphous iron phosphate
摘要：
The processes of acid in situ leaching (ISL) uranium (U) mines cause the pollution of groundwater. Phosphate (PO(4)(3-)) has the potential to immobilize U in groundwater through forming highly insoluble phosphate minerals, but the performance is highly restricted by low pH and high sulfate concentration. In this study, hydrogen peroxide (H(2)O(2)) and PO(4)(3-) were synergistically used for immobilizing U based on the specific properties of groundwater from a decommissioned acid ISL U mine. The removal mechanisms of U and the stability of U on the formed minerals were elucidated by employing X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and kinetic experiments. Our results indicated that the removal of U by simultaneously adding H(2)O(2) and PO(4)(3-) was significantly higher than the removal of U by individually adding H(2)O(2) or PO(4)(3-). The removal of U increased with increasing PO(4)(3-) concentration from 20 to 200 mg L(-1) while decreased with increasing H(2)O(2) concentration from 0.003 to 0.3%. Specifically, the removal efficiency of U from groundwater reached 98% after the application of 0.003% H(2)O(2) and 200 mg L(-1) PO(4)(3-). Amorphous iron phosphate that preferentially formed at low H(2)O(2) and high PO(4)(3-) concentrations played a dominant role in U removal, while the formations of schwertmannite and crystalline iron phosphates may be also contributed to the removal of U. This was significantly different from the immobilization mechanism of U through the formation of uranyl phosphate minerals after adding phosphate. The kinetic experimental results suggested that the immobilized U had a good stability. Our research may provide a promising method for in situ remediating U-contaminated groundwater at the decommissioned acid ISL U mines.
作者：
Ding, Dexin;Zhang, Qi;Zhang, Hui;Li, Guangyue;Hu, Nan
期刊：
Journal of Cleaner Production,2022年363:132601 ISSN：0959-6526
通讯作者：
Nan Hu
作者机构：
[Ding, Dexin; Zhang, Hui; Zhang, Qi; Li, Guangyue; Hu, Nan] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Min, Hengyang 421001, Peoples R China.;[Ding, Dexin; Hu, Nan] Hunan Prov Key Lab Green Dev Technol Extremely Low, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Nan Hu] K;Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, China<&wdkj&>Hunan Province Key Laboratory of Green Development Technology for Extremely Low Grade Uranium Resources, Hengyang, Hunan, 421001, China
关键词：
Bioaccumulation;Biochemistry;Bioremediation;Physiological models;Plants (botany);Sodium chloride;Superoxide dismutase;Uranium;Wetlands;Artificial wetland;Electric field intensities;Enhancement effects;Hydraulic retention;Leachate of urania tailing impoundment;Leachates;Phytoremediation;Retention time;Uranium tailings impoundments;Weak electric field;Electric fields
通讯机构：
[Dexin Ding] K;Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, People’s Republic of China<&wdkj&>School of Resource Environment and Safety Engineering, University of South China, Hengyang, People’s Republic of China
摘要：
Uranium (U) in the U-contaminated acidic red soil exhibits high mobility. In the present study, rice husk was used to produce biochar to remediate U-contaminated red soil under acid precipitation. Firstly, batch adsorption experiments showed that the dissolution of alkaline substance in biochar could buffer the pH value of acidic solution. The equilibrium pH value had a crucial influence on biochar adsorption capacity of U, and the neutral equilibrium pH value was favorable for adsorption. Then, the incubation experiments of red soil with biochar were performed, and the Synthetic Precipitation Leaching Procedure (SPLP) extraction of amended red soil showed that the short-term leachability of U was decreased from 26.53% in control group (without biochar) to 1.40% in 10% biochar-amended red soil. Subsequently, the sequential extraction showed that the fraction of U was mainly transformed from exchangeable and Fe/Mn oxide fraction to carbonate fraction after biochar amendment, and the total amount of exchangeable U and carbonate fraction U in soil was increased slightly. Finally, simulated acid rain leaching experiments showed that the capability of amended red soil to resist acid rain acidification was enhanced. And the long-term leachability of U in amended red soil was decreased from 26.37% in control group to 3.18% in the 10% biochar-amended red soil under the simulated acid rain leaching conditions. In conclusion, biochar has passivation effect on U in U-contaminated red soil, which can reduce the long-term and short-term mobility of U in acidic environments. This study provided an experimental basis for the application of biochar in remediation and improvement of U-contaminated acidic red soil.
作者机构：
南华大学铀矿冶生物技术国防重点学科实验室,衡阳421001;南华大学极贫铀资源绿色开发技术湖南省重点实验室,衡阳421001;[丁德馨; 张丹; 张悦; 马建洪; 谭国炽; 胡南; 张辉; 张琪] Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, China, Hunan Province Key Laboratory of Green Development Technology for Extremely Low Grade Uranium Resources, Hengyang, 421001, China
通讯机构：
[Ding, D.] K;[Ding, D.] H;Hunan Province Key Laboratory of Green Development Technology for Extremely Low Grade Uranium ResourcesChina;Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, China
通讯机构：
[Ding, Dexin] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.
关键词：
Uranium;Removal;Photoreduction;Wastewater
摘要：
Efficient elimination of U(VI) from uranium wastewater is an urgent task for sustainable nuclear energy and environmental protection. In this study, magnetic graphene oxide decorated graphitic carbon nitride (mGO/g-C3N4) nanocomposite was prepared and used for photocatalytic reduction of U(VI) in wastewater under visible LED light irradiation for the first time. The batch experiments indicated that the mGO/g-C3N4 (mGCN) nanocomposite could efficiently reduce U(VI) under visible LED light, and a high U(VI) extraction capacity of 2880.6 mg/g was obtained with an extraction efficiency of 96.02%. The transmission electron microscopy (TEM) elemental mapping, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analyses demonstrated that the soluble U(VI) was immobilized by transforming it to metastudtite ((UO2)O-2 center dot 2H(2)O) by mGCN nanocomposite under visible LED light irradiation. This work indicated that the mGCN is a promising visible light catalyst for treatment of uranium wastewater. (C) 2020 Elsevier Ltd. All rights reserved.
通讯机构：
Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, Hunan Province Key Laboratory of Green Development Technology for Extremely Low Grade Uranium Resources, University of South China, Hengyang, China
摘要：
Uranium-contaminated wastewater associated with uranium (U) mining and processing inevitably releases into soil environment. In order to assess the risk of U wastewater contamination to groundwater through percolation, U adsorption and transport behavior in a typical red soil in South China was investigated through batch adsorption and column experiments, and initial pH and carbonate concentration were considered of the high-sulfate background electrolyte solution. Results demonstrated that U adsorption isotherms followed the Freundlich model. The adsorption of U to red soil significantly decreased with the decrease of the initial pH from 7 to 3 in the absence of carbonate, protonation-deprotonation reactions controlled the adsorption capacity, and lnCs had a linear relationship with the equilibrium pH (pHeq). In the presence of carbonate, the adsorption was much greater than that in the absence of carbonate owing to the pHeq values buffered by carbonate, but the adsorption decreased with the increase of the carbonate concentration from 3.5 to 6.5 mM. Additionally, the breakthrough curves (BTCs) obtained by column experiments showed that large numbers of H(+) and CO3(2-) competed with the U species for adsorption sites, which resulted in BTC overshoot (C/C0 > 1). Numerical simulation results indicated that the BTCs at initial pH 4 and 5 could be well simulated by two-site chemical non-equilibrium model (CNEM), whereas the BTCs of varying initial carbonate concentrations were suitable for one-site CNEM. The fractions of equilibrium adsorption sites (f) seemed to correlate with the fractions of positively charged complexes of U species in solution. The values of partition coefficients (kd(')) were lower than those measured in batch adsorption experiments, but they had the same variation trend. The values of first-order rate coefficient (omega) for all BTCs were low, representing a relatively slow equilibrium between U in the liquid and solid phases. In conclusion, the mobility of U in the red soil increased with the decrease of the initial pH and with the increase of the initial carbonate concentrations.
摘要：
In this paper, the developmental toxicity and apoptosis in zebrafish (Danio rerio) embryos induced by 0.01, 0.05, and 0.10-Gy gamma-ray irradiation were investigated and verified by single cell gel electrophoresis, acridine orange staining, flow cytometry, transmission electron microscopy, digital gene expression sequencing, and Western blot analysis. DNA damage, deformity rates, and apoptosis of zebrafish embryos were found to increase significantly with the increase of irradiation dose, and survival and hatching rates significantly decreased when the irradiation dose exceeds 0.10 and 0.05 Gy, respectively. Exposure to 0.10-Gy gamma-ray irradiation resulted in the swelling of cell mitochondria of zebrafish embryos and changes in their intracellular vacuoles. mRNA and protein expression levels of Shh (sonic hedgehog 19 KDa) and Smo (smoothened 86 KDa) of Hh signaling pathway associated with the development of early embryos significantly increased with the increase of irradiation dose. Expression of the AKT (56 KDa) and PiK3r3 (55 KDa) genes, which are anti-apoptotic and involved with the PI3K/Akt signaling pathway, significantly decreased, while expression of the bada gene, which is pro-apoptotic, significantly increased. The results show that gamma-ray irradiations of 0.01 and 0.05 Gy can induce developmental toxicity and apoptosis in zebrafish embryos via Hh and PI3K/Akt signaling pathways, respectively.
作者机构：
[Dai, Zhongran; Sun, Yusu; Zhang, Hui; Ding, Dexin; Li, Le] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China
通讯机构：
[Ding, Dexin] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.
会议名称：
4th North American Symposium on Chemical Reaction Engineering (NASCRE)
会议时间：
MAR, 2019
会议地点：
Houston, TX
摘要：
Efficient removal of U(VT) from mine radioactive wastewater is important for environmental remediation and radiation protection. In this work, a new series of polyamidoxime/polydopamine-decorated graphene oxide (GO/PDA/PAO) composites were obtained by one-pot synthesis and used for the removal of U(VI) from mine radioactive wastewater. The as-synthesized GO/PDA/PAO composites (GO/PDA/PAO-0.2, GO/PDA/PAO-0.5, and GO/PDA/PAO-1) were examined by transmission electron microscopy, Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS). The effects of pH, ionic strength, contact time, initial U(VI) concentration, and temperature on the adsorption behavior of U(VI) by GO/PDA/PAO were investigated. The maximum adsorption capacity of GO/PDA/PAO-0.2 was 502.5 m g/g at pH 6.0 and 298 K. The adsorption kinetics and isotherms can be well illustrated by the pseudo-second-order kinetics model and Langmuir isotherm model. The thermodynamic study indicated that the removal of U(VI) by GO/PDA/PAO-0.2 was an endothermic and spontaneous process. The interactions between GO/PDA/PAO-0.2 and U(VI) were explained based on the FT-IR and XPS analyses. Furthermore, GO/PDA/PAO was applied for U(VI) removal from mine radioactive wastewater. The concentration of U(Vl) in the wastewater can be reduced to 7.28 /mu g/L, which is below the allowable uranium concentration for drinking water stipulated in the standard by the World Health Organization (30 mu g/L).
