铁在酸性矿井排水中的光化学起源
Huanxin Ma1, Shishu Zhu1, Ziyuan Huang1
1The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, P. R. China.
Environmental science & technology
|September 13, 2024
概括
一种新的光化学反应加速了酸性矿井排水 (AMD) 中的铁矿物质形成. 这种由阳光和氧气驱动的过程,揭示了对铁循环和重金属在污染水中的流动性的新见解.
科学领域:
- 环境化学环境化学
- 地质化学 地质化学
- 摄影化学的使用.
背景情况:
- 酸性矿井排水 (AMD) 构成了全球环境挑战,对铁循环产生重大影响.
- 虽然已知AMD中Fe(III) 矿物质形成的生物调节,但非生物过程仍未得到充分研究.
研究的目的:
- 研究非生物过程,特别是光化学在AMD中Fe (III) 矿物质形成中的作用.
- 阐明 AMD 影响水域加速铁氧化和花的机制.
主要方法:
- 在自然条件下 (北24-29°) 进行现场采样.
- 关于AMD的实验模拟.
- 在现场减弱的总反射率-里埃变换红外光谱法 (ATR-FTIR).
- 紫外线光谱,溶剂替代和量子产量分析.
- 密度函数理论 (DFT) 的计算和X射线吸收光谱学 (XAS).
主要成果:
- 与O2的光化学反应显著加快Fe(III) 叶片 (schwertmannite) 在AMD中的形成.
- 光生成的Fe (II) 物种,特别是[H2O) 5Fe]2+的内分子氧化被O2确定为增强Fe (II) 光氧化的关键机制.
- 有证据表明[H2O]5Fe]2+来源于通过电荷转移过程的溶解和合体Fe (III).
- 特定的Fe(II) 氧化途径产生反应性铁物种,促进水解和二二聚体的形成.
结论:
- 一个新的非生物光化学途径显著影响了AMD中的铁循环.
- 了解这些通路对于控制酸性环境中的重金属离子流动性至关重要.
- 这项研究提高了对铁生物化学在污染物和营养物质命运中的作用的理解.
相关概念视频
01:17Precipitation and Co-precipitation
1.7K
Precipitation and coprecipitation methods can be used to separate a mixture of ions in a solution. In qualitative inorganic analysis, ions that form sparingly soluble precipitates with the same reagent are separated based on the differences in solubility products. For example, consider the separation of Cu(II) and Fe(II) ions by precipitation as insoluble sulfides. First, copper(II) sulfide is precipitated by the addition of acidic H2S, where the dissociation of H2S is suppressed. Adding H2S...
1.7K
01:06Coagulation
278
Colloidal solids are solid particles suspended in solution. They are usually negatively charged, attracting a compact primary layer of positively charged ions, which attract more counterions to form an electrical double layer. Electrostatic repulsion between the charged double layers prevents the particles from colliding, stabilizing the colloids. These solids are often undesirable because they can contain toxins that are difficult to remove. Coagulation is a technique that helps aggregate and...
278
02:49Corrosion
23.9K
The degradation of metals due to natural electrochemical processes is known as corrosion. Rust formation on iron, tarnishing of silver, and the blue-green patina that develops on copper are examples of corrosion. Corrosion involves the oxidation of metals. Sometimes it is protective, such as the oxidation of copper or aluminum, wherein a protective layer of metal oxide or its derivatives forms on the surface, protecting the underlying metal from further oxidation. In other cases, corrosion is...
23.9K
01:09Colloidal precipitates
524
The high insolubility of some precipitates can result in an unfavorable relative supersaturation. This can lead to colloidal particles with a large surface-to-mass ratio, where adsorption is promoted. For instance, in the precipitation of silver chloride, silver ions are adsorbed on the surface of the colloidal particles, forming a primary layer. This layer attracts ions of opposite charge (such as nitrate ions), forming a diffuse secondary layer of adsorbed ions. This electric double layer...
524
04:01Factors Affecting Solubility
33.3K
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Chȃtelier’s principle. Consider the dissolution of silver iodide:
33.3K
00:56Extraction: Advanced Methods
432
Metal ions can be separated from one another by complexation with organic ligands–the chelating agent– to form uncharged chelates. Here, the chelating agent must contain hydrophobic groups and behave as a weak acid, losing a proton to bind with the metal. Since most organic ligands used in this process are insoluble or undergo oxidation in the aqueous phase, the chelating agent is initially added to the organic phase and extracted into the aqueous phase. The metal-ligand complex is...
432