Department of Agricultural, Environmental and Food Sciences (DIAAA), University of Molise, V. De Sanctis, I-86100, Campobasso (CB), Italy.
Department of Agricultural, Environmental and Food Sciences (DIAAA), University of Molise, V. De Sanctis, I-86100, Campobasso (CB), Italy.
Chemosphere. 2022 Sep;303(Pt 2):135172. doi: 10.1016/j.chemosphere.2022.135172. Epub 2022 May 29.
Goethite, hematite, ferrihydrite, and other iron oxides bind through various sorption reactions with humic substances (HS) in soils creating nano-, micro-, and macro-aggregates with a specific nature and stability. Long residence times of soil organic matter (SOM) have been attributed to iron-humic substance (Fe-HS) complexes due to physical protection and chemical stabilization at the organic-mineral interface. Humic acids (HA) and fulvic acids (FA) contain many acidic functional groups that interact with Fe oxides through different mechanisms. Due to the numerous interactions between mineral Fe and natural SOM, much research has led into a better identification and definition of HS. In this review, we first focus on the surface colloidal properties of Fe oxides and their reactivity toward HS. These minerals can be efficiently identified by usual techniques, such as XRD, FTIR spectroscopy, XAS, Mössbauer, diffuse reflectance spectroscopies (DRS), HRTEM, ATM, NanoSIMS. Second, we present the recent state of art regarding the adsorption/precipitation of HS onto iron mineral surfaces and their effects on binding metalloid and trace elements. Finally, we consider future research directions based on recent scientific literature, with particular focus on the ability of Fe nano-particles to increase Fe bioavailability, improve carbon sequestration, reduce greenhouse gas emissions, and decrease the impact of persistent organic and inorganic pollutants. The methodology in this field has rapidly developed over the last decade. However, new procedures to estimate the nature of Fe-HA bonds will be important contributions in clarifying the role of natural iron oxides in soil for carbon stabilization.
针铁矿、赤铁矿、水铁矿和其他氧化铁通过与土壤中腐殖质（HS）的各种吸附反应结合，形成具有特定性质和稳定性的纳米、微米和宏观团聚体。由于铁-腐殖质（Fe-HS）复合物在有机-矿物界面的物理保护和化学稳定作用，土壤有机质（SOM）的长停留时间归因于铁-腐殖质复合物。腐殖酸（HA）和富里酸（FA）含有许多酸性官能团，通过不同的机制与 Fe 氧化物相互作用。由于矿物 Fe 与天然 SOM 之间存在众多相互作用，因此大量研究导致了对 HS 的更好识别和定义。在这篇综述中，我们首先关注 Fe 氧化物的表面胶体性质及其对 HS 的反应性。这些矿物可以通过 XRD、FTIR 光谱学、XAS、穆斯堡尔、漫反射光谱学（DRS）、HRTEM、ATM、NanoSIMS 等常用技术进行有效鉴定。其次，我们介绍了关于 HS 在铁矿物表面吸附/沉淀及其对结合类金属和痕量元素的影响的最新研究进展。最后，我们根据最近的科学文献考虑了未来的研究方向，特别关注 Fe 纳米颗粒提高 Fe 生物利用度、促进碳封存、减少温室气体排放以及降低持久性有机和无机污染物影响的能力。该领域的方法学在过去十年中得到了快速发展。然而，估计 Fe-HA 键性质的新程序将是阐明天然氧化铁在土壤中对碳稳定作用的重要贡献。
