(VI) 和 (IV) 的生物还原:实验和热力学研究
Jinchuan Xie1, Dongyan Li1, Yu Wang2
1Institute of Military-Civilian Integration Technology, Northwest University of Political Science and Law, Xi'an, Shaanxi, 710122, China.
Journal of environmental radioactivity
|December 19, 2023
概括
通过Shewanella putrefaciens研究了 (U(VI) aq) 和 (Pu(IV) am的生物还原. 碳酸减缓了U(VI) aq生物还原,而酸则在无毒条件下促进了Pu(IV) am生物还原.
科学领域:
- 环境科学 环境科学
- 地质化学 地质化学
- 微生物学 微生物学
背景情况:
- 了解 (U) 和 (Pu) 等活性化物的环境命运对于风险评估至关重要.
- 微生物的生物还原是影响重金属在地下环境中的移动性和物种化的关键过程.
- 谢瓦内拉 (Shewanella putrefaciens) 以其能够减少广泛的金属氧化物而闻名.
研究的目的:
- 为了研究U(VI)aq和Pu(IV) am.am.的实验和热力学生物还原.
- 为了预测地下水中U和Pu的传输速度.
- 评估与U和Pu相关的环境污染风险.
主要方法:
- 使用Shewanella putrefaciens研究了U(VI)aq和Pu(IV) am的生物减少.
- 研究了碳酸和酸在pH7.1无氧溶液中的碳酸和酸的影响.
- 分析了热力学参数,包括在实验条件下标准的氧化还原潜力和氧化还原潜力.
主要成果:
- 在NaHCO3/CaCl2的存在下,U(VI) aq的生物还原率显著降低,这是由于三元复合物的标准氧化还原潜力更为负.
- 二的生物还原是可行的,酸作为电子受体,由低于PuO2/Pu3+的氧化还原潜力促进.
- 与U(VI)aq (74.9%) 相比,观察到的Pu(IV) am (8.9%) 的低减少程度归因于微量级的Pu3+活性的化学因子,导致负的氧化还原潜力.
结论:
- 碳酸和酸对Shewanella putrefaciens产生的U{VI}aq和Pu{IV}am生物还原的速度和程度有很大的影响.
- 热力学因素,包括复杂化和氧化还原潜力,在控制金属生物还原方面发挥着至关重要的作用.
- 微量Pu(IV) am物种化和相关的氧化还原潜力变化是理解其在研究环境中的有限生物还原的关键.
更多相关视频
相关概念视频
Redox Equilibria: Overview
564
A reduction-oxidation reaction is commonly called a redox reaction. In a redox reaction, electrons are transferred from one species to another rather than being shared between or among atoms. The reducing agent or reductant is the species that loses electrons and gets oxidized in the process. The species that gains electrons and gets reduced in the process is the oxidizing agent or oxidant. Redox reactions are represented as two separate equations called half-reactions, where one equation...
564
Ladder Diagrams: Redox Equilibria
460
Ladder diagrams are useful tools for understanding redox equilibrium reactions, especially the effects of concentration changes on the electrochemical potential of the reaction. The vertical axis in the redox ladder diagrams represents the electrochemical potential, E. The area of predominance is demarcated using the Nernst equation.
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
460
Redox Titration: Other Oxidizing and Reducing Agents
294
Besides iodine, other oxidizing or reducing agents can serve as titrants in redox titrations. Common oxidizing titrants include KMnO4, cerium(IV), and K2Cr2O7. The choice of oxidizing titrants depends on factors like stability, cost, analyte strength, and reaction rate between the analyte and titrant. KMnO4 is a strong oxidizing titrant that reduces from Mn(VII) to Mn(II) in a highly acidic solution, simultaneously oxidizing the analyte to a higher oxidation state. In this case, KMnO4 acts as a...
294
Free Energy Changes for Nonstandard States
11.4K
The free energy change for a process taking place with reactants and products present under nonstandard conditions (pressures other than 1 bar; concentrations other than 1 M) is related to the standard free energy change according to this equation:
where R is the gas constant (8.314 J/K·mol), T is the absolute temperature in kelvin, and Q is the reaction quotient. This equation may be used to predict the spontaneity of a process under any given set of conditions.
Reaction Quotient...
where R is the gas constant (8.314 J/K·mol), T is the absolute temperature in kelvin, and Q is the reaction quotient. This equation may be used to predict the spontaneity of a process under any given set of conditions.
Reaction Quotient...
11.4K
Oxidation of Phenols to Quinones
3.1K
In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen.
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox...
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox...
3.1K
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
1.8K
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
1.8K


