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.
期刊：
Journal of Environmental Radioactivity,2019年208:106036 ISSN：0265-931X
通讯作者：
Ding, De-xin
作者机构：
[Chen, Si-yu; Dai, Zhong-ran; Zhang, Hui; Hu, Nan; Sha, Yin-hua; Ding, De-xin] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Henyang 421001, Peoples R China.;[Zou, Chao; Wang, Yong-dong] Univ South China, Hunan Prov Key Lab Green Dev Technol Exetremely L, Henyang 421001, Peoples R China.;[Ding, De-xin] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 West Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, De-xin] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 West Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
关键词：
Artificial plant community plot;Contaminated soil;Enhanced phytoremediation;Uranium
摘要：
In order to develop an artificially constructed plant community plot for the enhanced phytoremediation of uranium contaminated soils, three uranium accumulators including Bamboo-willow (Salix sp.), Paspalum scrobiculatum linn and Macleaya cordata were used to construct four artificial plant community plots, and greenhouse experiments were conducted to investigate the bioaccumulation of uranium by the plants and the organic acid content, enzyme activity, and the change of microbial community structure in their rhizosphere soils. The transfer factor (TF) and the total bioaccumulation amount (TBA) of uranium were used to describe remediation efficiencies in this paper. It was found that their remediation efficiencies were in the order Bamboo-willow (Salix sp.)-Paspalum scrobiculatum linn-Macleaya cordata > Bamboo-willow (Salix sp.)-Macleaya cordata > Paspalum scrobiculatum linn-Macleaya cordata > Bamboo-willow (Salix sp.)-Paspalum scrobiculatum linn. The bioaccumulation amount of uranium by each plant in the Bamboo-willow (Salix sp.)-Paspalum scrobiculatum linn-Macleaya cordata community plot was significantly (P < 0.05) higher than that by its single population, the bioaccumulation amounts of uranium by Bamboo-willow (Salix sp.), Paspalum scrobiculatum linn and Macleaya cordata were 0.29, 0.32 and 2.19 mg/plant, respectively, and they were increased by 31.82%, 77.78% and 146.07%, respectively, and the transfer efficiencies by the plants were increased by 150%, 110% and 52.17%, respectively. The interaction between the plants' roots and the microorganisms in the rhizosphere soil of the Bamboo-willow (Salix sp.)-Paspalum scrobiculatum linn-Macleaya cordata community plot resulted in the high content of organic acids such as oxalic acid in the rhizosphere soil of the plant community plot, which was significantly (P < 0.05) higher than that of its single population. The chelation of the organic acids with uranium led to an increase in the proportion of exchangeable uranium in soil solution. In addition, Burkholderia, which is an iron-producing carrier bacterium and can increase the uptake and accumulation of uranium by plants, and Leptolyngbya, which is a plant growth promoting rhizobacteria and can increase the biomass of plants, emerged in the rhizosphere soil of the plant community plot. These may be the mechanisms by which the phytoremediation of the uranium contaminated soils was enhanced by the plant community plot.
作者机构：
[Li Feng; Zou Chao; Dai Zhong-ran; Ding De-xin; Li Guang-yue; Hu Nan; Wang Yong-dong; Cui Yue-ting; Sun Jing; Sha Yin-hua; Zhang Hui] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Heng Yang 421001, Hunan, Peoples R China.
通讯机构：
[Wang Yong-dong] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Heng Yang 421001, Hunan, Peoples R China.
期刊：
American Journal of Biochemistry and Biotechnology,2018年14(2):145-153 ISSN：1553-3468
通讯作者：
Ding, De-Xin(dingdxzzz@163.com)
作者机构：
[Cao, Yun-Chang; Hu, Nan; Wang, Yong-Dong; Li, Gaung-Yue; Ding, De-Xin] Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, 28 West Changsheng Rd, Hengyang;Hunan;421001, China;[Wen, Hong-Bo] Department of Biochemistry and Molecular Biology, School of Pharmaceutical and Biological Science, University of South China, 28 West Changsheng Rd, Hengyang;[Cao, Yun-Chang; Wen, Hong-Bo; Hu, Nan; Wang, Yong-Dong; Li, Gaung-Yue; Ding, De-Xin] Hunan
通讯机构：
[Ding, D.-X.] K;Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, 28 West Changsheng Rd, Hengyang, Hunan, China
作者机构：
[李殿鑫; 胡南; 黄超; 丁德馨; 李广悦; 王永东] Key Discipline Laboratory for National Defence for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang;Hunan;421001, China;Hunan Province Key Laboratory of Green Development Technology for Extremely Low Grade Uranium Resources, University of South China, Hengyang;[李殿鑫; 胡南; 黄超; 丁德馨; 李广悦; 王永东] Hunan
通讯机构：
Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, China
通讯机构：
[Ding, De-xin] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.
关键词：
Gold bearing high arsenic sulphide concentrate;Microwave roasting;Water content;Iodide/iodine leaching
摘要：
A new technology for enhancing microwave roasting of gold bearing high arsenic sulphide concentrate with various water contents was proposed. The influence of water content and roasting time on microwave roasting of gold concentrate was investigated, and the mechanism of microwave roasting of gold bearing high arsenic sulphide concentrate with various water contents was analyzed. The results show that the removal rate of sulfur and iodide/iodine leaching rate of gold are mainly dependent on water content. The removal rate of sulfur and the leaching rate of gold reaches 87.95% and 75.08%, respectively, under the conditions of water content of 9% with microwave roasting for 30 min. After the dried concentrate sample and the wetted concentrate sample with 9% water content were roasted in the microwave oven for 60 min, the latter was found by SEM to be more porous than former, its specific surface area was found to increase from 25.6 to 32.7 m(2)/g. (C) 2017 Elsevier B.V. All rights reserved.
摘要：
The endophyte Pseudomonas sp. XNN8 was separated from Typha orientalis which can secrete indole-3-acetic acid and 1-aminocyclopropane-1-carboxylate deaminase and siderophores and has strong resistance to uranium it was then colonized in the Syngonium podophyllum; and the S. podophyllum-Pseudomonas sp. XNN8 symbiotic purification system (SPPSPS) for uranium-containing wastewater was constructed. Afterwards, the hydroponic experiments to remove uranium from uranium-containing wastewater by the SPPSPS were conducted. After 24 days of treatment, the uranium concentrations of the wastewater samples with uranium concentrations between 0.5 and 5.0 mg/L were lowered to below 0.05 mg/L. Furthermore, the uranium in the plants was assayed using Fourier transform infrared spectroscopy (FTIR) and extended X-ray absorption fine structure (EXAFS) spectroscopy. The Pseudomonas sp. XNN8 was found to generate substantial organic groups in the roots of the Syngonium podophyllum, which could improve the complexing capability of S. podophyllum for uranium. The uranium in the roots of S. podophyllum was found to be the uranyl phosphate (47.4 %) and uranyl acetate (52.6 %).
摘要：
The anaerobic microcosms amended with 30 mM bicarbonate and without bicarbonate were established, respectively, and the reduction of U(VI) in the microcosms by functionalized indigenous microbial communities was investigated. Results of the chemical extraction and XANES analysis showed that the proportions of U(IV) in the microcosms amended with bicarbonate were 10 % lower than without bicarbonate at day 46. The amount of Cellulomonadaceae, Desulfovibrionaceae, Peptococcaceae and Veillonellaceae amended with bicarbonate was lower than without bicarbonate, so the reduction of U(VI) was less. The experimental results show that the high concentration bicarbonate has a significantly inhibitory effect on the reduction of U(VI).
