Biochar, carbonaceous material produced from biomass pyrolysis, has been demonstrated to have electron transfer property(associated with redox active groups and multi condensed aromatic moiety), and to be also involve...Biochar, carbonaceous material produced from biomass pyrolysis, has been demonstrated to have electron transfer property(associated with redox active groups and multi condensed aromatic moiety), and to be also involved in biogeochemical redox reactions. In this study, the enhanced removal of Cr(VI) by Shewanella oneidensis MR-1(MR-1) in the presence of biochars with different pyrolysis temperatures(300 to 800 ℃) was investigated to understand how biochar interacts with Cr(VI) reducing bacteria under anaerobic condition. The promotion effects of biochar(as high as 1.07~1.47 fold) were discovered in this process, of which the synergistic effect of BMBC700(ball milled biochar) and BMBC800 with MR-1 was noticeable, in contrast, the synergistic effect of BMBCs(300–600 ℃) with MR-1 was not recognized. The more enhanced removal effect was observed with the increase of BMBC dosage for BMBC700 + MR-1 group. The conductivity and conjugated O-containing functional groups of BMBC700 particles themselves has been proposed to become a dominant factor for the synergistic action with this strain. And, the smallest negative Zeta potential of BMBC700 and BMBC800 is thought to favor decreasing the distance from microbe than other BMBCs. The results are expected to provide some technical considerations and scientific insight for the optimization of bioreduction by useful microbes combining with biochar composites to be newly developed.展开更多
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
基金The study was supported by the Natural Science Foundation of Tianjin(No.20JCZDJC00700)the National Natural Science Foundation of China(Nos.U1806216,41877372)+1 种基金the National Key R&D Program of China(No.2018YFC1802002)111 program,Ministry of Education,China(No.T2017002).
文摘Biochar, carbonaceous material produced from biomass pyrolysis, has been demonstrated to have electron transfer property(associated with redox active groups and multi condensed aromatic moiety), and to be also involved in biogeochemical redox reactions. In this study, the enhanced removal of Cr(VI) by Shewanella oneidensis MR-1(MR-1) in the presence of biochars with different pyrolysis temperatures(300 to 800 ℃) was investigated to understand how biochar interacts with Cr(VI) reducing bacteria under anaerobic condition. The promotion effects of biochar(as high as 1.07~1.47 fold) were discovered in this process, of which the synergistic effect of BMBC700(ball milled biochar) and BMBC800 with MR-1 was noticeable, in contrast, the synergistic effect of BMBCs(300–600 ℃) with MR-1 was not recognized. The more enhanced removal effect was observed with the increase of BMBC dosage for BMBC700 + MR-1 group. The conductivity and conjugated O-containing functional groups of BMBC700 particles themselves has been proposed to become a dominant factor for the synergistic action with this strain. And, the smallest negative Zeta potential of BMBC700 and BMBC800 is thought to favor decreasing the distance from microbe than other BMBCs. The results are expected to provide some technical considerations and scientific insight for the optimization of bioreduction by useful microbes combining with biochar composites to be newly developed.
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.
