Anthraquinone-2-sulfonate（AQS） was employed in humus substitutes to evaluate the effects and influencing factors of U（VI） reduction by Shewanella oneidensis MR-1（S. oneidensis MR-1） under anaerobic condition. Th...Anthraquinone-2-sulfonate（AQS） was employed in humus substitutes to evaluate the effects and influencing factors of U（VI） reduction by Shewanella oneidensis MR-1（S. oneidensis MR-1） under anaerobic condition. The removal rate of U（VI） at 30 °C reaches 99.0% afterd 96 h with the p H value of 7.0 and AQS concentration of 1.0 mmol/L. The effective concentrations of AQS as the accelerator for U（VI） bioreduction are approximately 0.5-1.0 mmol/L. The bioreduction of U（VI） is inhibited when the concentration of AQS exceeds 2.0 mmol/L. The coexistence of ions, such as Cu2＋, Cr6＋, Mn2＋, shows a remarkable negative effect on the U（VI） reduction, and Zn2＋ shows less influence on the process compared with other tested ions. The U（VI） reduction is remarkably inhibited when the concentration of nitrate ion exceeds 1.0 mmol/L. Otherwise, no difference is found when the nitrate ion concentration is less than 0.5 mmol/L. Sulfate ion（5.0 mmol/L） slightly promotes the U（VI） reduction. Zero-valent iron（ZVI） promotes the U（VI） reduction by S. oneidensis, and the reduction rate improves with increasing the amount of ZVI in the range of 0-2.0 g/L. The XPS result indicates that uranium deposits on the cell surface are in U（VI） and U（IV） forms, and the majority of uranium in the solution is stable UO2.展开更多
The microstructures and growth process characteristics precipitation-crystallization method were investigated by SEM, TEM of spherical Ni（OH）2 particles synthesized by the aqueous and XRD, and their growth mechanism...The microstructures and growth process characteristics precipitation-crystallization method were investigated by SEM, TEM of spherical Ni（OH）2 particles synthesized by the aqueous and XRD, and their growth mechanism was discussed. With the reaction beginning and continuing, amorphous Ni（OH）2 nano-crystallites grow up to spherical micron-particles with radially arranged crystallites. The nucleation, crystallization and re-crystallization led by Ostwald ripening simultaneously take place through the whole growth processes. With the course from reversible aggregation to irreversible agglomeration, the Ni（OH）2 particles tend to grow according to the template growth model： the growth on the crystallite templates stretching in the radius directions is free and quick, while the growth rate for crystallites in other directions is confined due to lower monomers concentration and tends to dissolve So it is only the radially arranged crystallites that predominate in the particle and lead to characteristic microstructures.展开更多
基金Projects(1117508111475080)supported by the National Natural Science Foundation of China+3 种基金project(13JJ3078)supported by the Natural Science Foundation of Hunan ProvinceChinaProject(14k083)supported by the Innovation Platform Open Fund Project of University in Hunan ProvinceChina
文摘Anthraquinone-2-sulfonate（AQS） was employed in humus substitutes to evaluate the effects and influencing factors of U（VI） reduction by Shewanella oneidensis MR-1（S. oneidensis MR-1） under anaerobic condition. The removal rate of U（VI） at 30 °C reaches 99.0% afterd 96 h with the p H value of 7.0 and AQS concentration of 1.0 mmol/L. The effective concentrations of AQS as the accelerator for U（VI） bioreduction are approximately 0.5-1.0 mmol/L. The bioreduction of U（VI） is inhibited when the concentration of AQS exceeds 2.0 mmol/L. The coexistence of ions, such as Cu2＋, Cr6＋, Mn2＋, shows a remarkable negative effect on the U（VI） reduction, and Zn2＋ shows less influence on the process compared with other tested ions. The U（VI） reduction is remarkably inhibited when the concentration of nitrate ion exceeds 1.0 mmol/L. Otherwise, no difference is found when the nitrate ion concentration is less than 0.5 mmol/L. Sulfate ion（5.0 mmol/L） slightly promotes the U（VI） reduction. Zero-valent iron（ZVI） promotes the U（VI） reduction by S. oneidensis, and the reduction rate improves with increasing the amount of ZVI in the range of 0-2.0 g/L. The XPS result indicates that uranium deposits on the cell surface are in U（VI） and U（IV） forms, and the majority of uranium in the solution is stable UO2.
基金Project(50134020) supported by the National Natural Science Foundation of ChinaProject supported by Postdoctoral Fund of Central South University
文摘The microstructures and growth process characteristics precipitation-crystallization method were investigated by SEM, TEM of spherical Ni（OH）2 particles synthesized by the aqueous and XRD, and their growth mechanism was discussed. With the reaction beginning and continuing, amorphous Ni（OH）2 nano-crystallites grow up to spherical micron-particles with radially arranged crystallites. The nucleation, crystallization and re-crystallization led by Ostwald ripening simultaneously take place through the whole growth processes. With the course from reversible aggregation to irreversible agglomeration, the Ni（OH）2 particles tend to grow according to the template growth model： the growth on the crystallite templates stretching in the radius directions is free and quick, while the growth rate for crystallites in other directions is confined due to lower monomers concentration and tends to dissolve So it is only the radially arranged crystallites that predominate in the particle and lead to characteristic microstructures.
