摘要：
A defined mixed bioleaching consortium (constructed by Acidithiobacills ferrooxidans ATCC 23270, Leptospirillum ferriphilum YSK, Sulfobacillus thermosulfidooxidans ST, Acidithiobacills thiooxidans A01 and Acidithiobacills caldus S1) was used to investigate the fluoride stress response. The results showed that its growth and iron oxidation rate were obviously inhibited, while the sulphur oxidation was only barely restrained. Furthermore, the community dynamics and gene expression were assayed respectively by using real-time quantitative polymerase chain reaction assay (RT-PCR) and functional gene arrays (FGAs). From the analysis of community dynamics, the most obviously inhibited strains were S. thermosulfidooxidans ST, while L. ferriphilum YSK still maintained stable growth. After 4.8 mM of fluoride stress for 28 h, the S. thermosulfidooxidans cell concentration was decreased by about 517.8 times more than in non-stress state. From the analysis of gene expression, fluoride stress was seen to exert pleiotropic effects on different species in the consortium. The dominant species played the pivotal role in resisting fluoride stress and maintaining activities in the system, yet the inferior species also had a critical function of assisting the survival of the dominant species.
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：
In situ leaching;Groundwater;Bioreduction;U(VI);Anaerobic zone
摘要：
To determine whether the U(VI) in groundwater under anoxic conditions at a decommissioned in situ leaching (ISL) uranium mine could be bioreduced, groundwater samples containing suspended sediments were taken from the mine, experimental setup was fabricated, and the jar containing the groundwater in the setup was amended with ethanol and incubated under anoxic conditions. The variations of pH, chemical oxygen demand, nitrate, sulfate, U(VI), and dissolved oxygen (DO) concentrations were monitored during the incubation. U(VI) concentration dropped to 0.043 mg/L when the stimulated microorganisms were active, and it then increased to 0.835 mg/L within 10 days after the metabolism of the stimulated microorganisms was inhibited. The DO variation was observed in the amended jar during the incubation, and the metabolism of the stimulated microorganisms was found to affect the DO concentration. Firmicutes were found to be dominant in the sediments in the amended jar through the 16S rRNA pyrosequencing. The results indicate that it is possible to bioreduce U(VI) in the groundwater under anoxic conditions at the decommissioned ISL uranium mine by adding carbon source into it without removing the oxygen from it.
摘要：
An absorptive fungal strain for uranium adsorption which is named Q5, was isolated from the drainage of a uranium mine in South China. The morphological, physiological and phylogenetic characterizations of the strain Q5 were investigated. The results showed that, the strain Q5 identified as Penicillium funiculosum (99 % similarity in gene sequence). Furthermore, the adsorption performance of P. funiculosum was greatly improved by the mutational method that combined hydroxylamine hydrochloride and UV light. The results showed that the adsorption capacity of the mutated P. funiculosum for U(VI) was obviously better than the non-mutational one at pH 2.0–9.0.
摘要：
In order to reveal the nonlinear dynamics characteristics of unsteady self-heating process of sulfide ores, nine different kinds of sulfide ore samples from a pyrite mine in China were taken as experimental materials and their self-heating characteristics were measured in laboratory. Furthermore, the measured temperature was studied by integrating wavelet transform, nonlinear characteristic parameters extraction and fuzzy comprehensive evaluation. The results indicate that only the ore samples 1, 2, 6 and 9 have obvious self-heating phenomenon, and their self-heating initiative temperatures are 220 ℃, 239 ℃, 220 ℃ and 220 ℃,respectively, which means that they are difficult to produce self-heating under normal mining conditions. The correlation dimension of self-heating process is fraction and the maximum Lyapunov exponent is positive, which means that it is feasible to study the self-heating process based on chaotic dynamics theory. The nonlinearities of self-heating process of these four samples (ore samples 1, 2, 6 and 9) are 0.8227, 0.7521, 0.9401 and 0.8827 respectively and the order of the samples according to these results is: sample 6,sample 9, sample 1, sample 2, which is consistent with the measured results of self-heating characteristics. Therefore, the nonlinearity method can be used to evaluate the self-heating tendency of sulfide ores, and it is an effective verification of the reliability of measured results.
作者机构：
[Wen, Xia] Univ South China, Sch Nucl Resources Engn, Hengyang 421001, Peoples R China.;[Wen, Xia; Zhao, Junming; Mason, Roger; Sang, Longkang; Ma, Changqian] China Univ Geosci, State Key Lab Geol Proc & Min Resources, Wuhan 430074, Peoples R China.;[Wen, Xia; Zhao, Junming; Mason, Roger; Sang, Longkang; Ma, Changqian] China Univ Geosci, Sch Earth Sci, Wuhan 430074, Peoples R China.
通讯机构：
[Ma, Changqian] C;China Univ Geosci, State Key Lab Geol Proc & Min Resources, Wuhan 430074, Peoples R China.
关键词：
accreted lapilli;cone-sheets;alkaline ring complex;K-feldspar fractionation;ignimbrite;Houshihushan alkaline ring complex
摘要：
In addition to syenite ring dykes and multiple alkaline granite stocks, the sub-volcanic Houshihushan alkaline ring complex near Shanhaiguan, Qinhuangdao City, contains cone-sheets of two types: a majority filled with granite porphyry and a minority filled with quartz syenite porphyry. Many cone sheets show evidence of multiple magma intrusion events. Some granite porphyry sheets’ multiple chilled margins display magmatic roll structures indicating that turbulent magma flowed up the fractures. In one upward-closing cone-sheet K-feldspar phenocrysts floated up through fluid granite porphyry magma and became concentrated at the top providing direct evidence of shallow-level crystal fractionation, confirmed by published rock analyses. Accreted lapilli with K-feldspar crystal cores occur only in the inner parts of a minority of cone-sheets and field relationships indicate that they must have formed beneath the ground surface. Similar lapilli occur in erupted ignimbrites preserved in the collapsed caldera. Voids between lapilli in cone-sheets indicate the presence of volumes of gas below the surface that could have flowed upwards as fast-moving hot gas streams. We propose a mechanism of formation that began with subterranean magmatic rolls with K-feldspar crystal cores that formed on dyke walls, and became detached. Then they were caught up in rising gas streams and erupted at the surface. Thus accreted lapilli formed underground, were erupted along with blobs of fluid glass in escaping gases, and transported over the surface in nuées ardentes, to settle and cool as ignimbrite flows.
期刊：
Journal of Radioanalytical and Nuclear Chemistry,2014年299(3):1903-1909 ISSN：0236-5731
通讯作者：
Ding, Dexin
作者机构：
[Ding, Dexin; Li, Guangyue; Hu, Nan; Xin, Xin; Fu, Pingkun] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.;[Li, Le] Univ South China, Sch Publ Hlth, 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.
关键词：
Sodium feldspar;U(VI) ion adsorption;Low concentration aqueous solution;Kinetic;Water treatment
摘要：
The raw sodium feldspar (RSF) is activated with the concentrated sulfuric acid solution and the acid activated sodium feldspar (AASF) is obtained. The results obtained from the mercury intrusion method show that the acidification can increase the porosity and the specific surface area. The effects of the initial pH, contact time and ambient temperature on the adsorption of U(VI) ions are investigated in a batch process. The adsorption efficiency amounts to the highest at pH 6 and the adsorption equilibrium is reached in 600 min. The pseudo-second-order model is found to be more suitable for the adsorption process than the pseudo-first-order model and intra-particle model, indicating that the chemical adsorption is the predominant step for the adsorption process. Langmuir model is found to describe the adsorption process better than Freundlich model. This proves that the main form of U(VI) ions attached to RSF and AASF is the monolayer coverage. The thermodynamic parameters prove that the adsorption process is a spontaneous endothermic one. It was also found that acid activated treatment can help increase the adsorption rate and capacity. The results show that RSF and AASF can be used as a novel low cost adsorbent for removal of U(VI) ions from the low concentration aqueous solution.
摘要：
In order to develop an effective and economical method for removing U(VI) from the low concentration radioactive wastewater with the U(VI) concentration of less than 1 mg L<sup>-1</sup>, the biomass of Aspergillus niger was prepared and modified with ethylenediamine, and the biosorption of uranium from the low concentration radioactive wastewater by the unmodified and the modified biomasses was investigated in a batch system. The modified biomass exhibited the adsorption efficiency of 99.25 % for uranium under the optimum conditions that pH was 5.0, the contact time was 150 min, and the biosorbent dose was 0.2 g L<sup>-1</sup>. The adsorption fitted well to Langmuir isotherm, and the maximum sorption capacity of the modified biomass for U(VI) was determined to be 6.789 mg g<sup>-1</sup> which increased by 36.45 % compared with the unmodified biomass. The adsorption kinetics was better depicted by pseudo-second-order kinetic model. The Gibbs free energy change (ΔG <sup>0</sup>), enthalpy change (ΔH <sup>0</sup>), and entropy change (ΔS <sup>0</sup>) showed that the process of U(VI) adsorption was spontaneous, endothermic, and feasible. The changes in the groups, morphology, and the presence of U(VI) on the surface of the adsorbents which were characterized by FT-IR, SEM, and EDS, demonstrated that the U(VI) was successfully adsorbed onto the modified biomass. Moreover, the UO<inf>2</inf> <sup>2+</sup> absorbed on the modified biomass can be released by 0.1 mol L<sup>-1</sup> HNO<inf>3</inf> with high desorption efficiency of 99.21 %. The results show that the modified biomass can remove U(VI) from low concentration radioactive wastewater more effectively than the unmodified biomass.
通讯机构：
[Tan, Kaixuan] U;Univ South China, Sch Nucl Resources Engn, Hengyang 421001, Peoples R China.
关键词：
Complex surfactant;Leaching kinetics;Resin adsorption and elution;Low permeable sandstone uranium deposit;In-situ leaching of uranium mining
摘要：
Applications of a complex surfactant developed in-house to in-situ leaching of low permeable sandstone uranium deposits are described based on results from agitation leaching, column leaching, resin adsorption, and elution experiments using uranium containing solution from the in-situ leaching site. The results of agitation leaching experiments show that adding surfactant with different concentrations into leaching solution improves the leaching rate of uranium. The maximum leaching rate of uranium from agitation leaching reached 92.6% at an added surfactant concentration of 10 mg/l. Result of column leaching experiment shows that adding surfactant with varying concentrations into leaching solutions increased the permeability coefficient of ore-bearing layer by 42.7-86.8%. The leaching rate of uranium from column leaching increased by 58.0% and reached 85.8%. The result of kinetic analysis shows that for the extraction of uranium controlled by diffusion without surfactant the apparent rate constant 0.0023/d changed to 0.0077/d for the extraction with surfactant controlled by both diffusion and surface chemical reactions. Results from resin adsorption and elution experiments show that there was no influence on resin adsorption and elution of uranium with an addition of 50 mg/l surfactant to production solution from in-situ leaching. The adsorption curve, sorption capacity of resin, recycling of resin remained the same as without adding any surfactant. Introducing complex surfactant to leaching solution increased the peak concentration of uranium in eluents, reduced the residual uranium content in resin, and promoted the elution efficiency. The method of using a complex surfactant for in-situ leaching is useful for low permeable sandstone uranium deposits. (C) 2014 Elsevier B.V. All rights reserved.
摘要：
In order to investigate the mechanism of extracellular polymeric substances (EPS) influencing sludge characteristics, variations of extractable EPS from municipal sewage sludge by acid/alkaline pretreatment and gamma-ray irradiation were studied. The changes in constituents of EPS were analyzed by UV-vis spectra and SEM images. The effects of alkaline pretreatment and gamma-ray irradiation on the functional groups in EPS were investigated by Fourier transform infrared (FTIR) spectrometer. Results showed that the extractable EPS increased clearly with increasing irradiation dose from 0 to 15 kGy. UV-vis spectra indicated that a new absorption band from 240 nm to 300 nm existed in all irradiated samples, apart from acid condition. The results of FTIR spectroscopic analysis indicated that, irradiation influenced major functional groups in EPS, such as protein and polysaccharide, and these effects were clearer under alkaline condition. SEM images provided that after alkaline hydrolysis, gamma-ray irradiation was more effective in resulting in the sludge flocs and cells broken, compared with acid pretreatment (pH 2.50). (c) 2013 Published by Elsevier Ltd.
