Mutual interactions of organic matter with soil minerals: kinetics, adsorption modes, transformation and stability of complexes

有机质与土壤矿物质的相互作用：动力学、吸附模式、复合物的转化和稳定性

• 批准号: 436804888
• 负责人: Professor Dr. Thilo Rennert
• 金额: --
• 依托单位: Department of Soil and Water Sciences
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/436804888?language=en
• 关键词: Mutual; interactions; organic; matter; soil

Soil organic matter (SOM) is the most important sink for organic carbon in terrestrial ecosystems. Adsorption of SOM by mineral surfaces is one of the major stabilization mechanisms that decelerate the decomposition of SOM. SOM comprises a variety of organic compounds with different chemical structures and properties, potentially interacting with minerals. However, the mechanisms of the mutual interactions of these chemical compounds with soil minerals, and the impacts of these interactions on the stability of both SOM and minerals in SOM-mineral complexes are not yet clarified. In the proposed project, we suggest a novel approach considering composition and structure of both SOM and minerals. We plan to carry out a systematic study on the mutual interactions of important SOM constituents (phenolic acids, cutin monomers, peptides) with soil minerals – montmorillonite, and Fe and Mn oxides (ferrihydrite, birnessite) of varying crystallinity. We will study the fast kinetics to estimate the mode and energy of SOM adsorption by minerals. We will apply state-of-the-art analytical techniques (LC/MS and XPS) to elucidate the mechanisms of competitive or cooperative adsorption and transformation of different SOM compounds by minerals, and the impact of these interactions on the stability/alteration of the oxides. We will apply two scenarios to investigate adsorption and transformation of organic compounds by minerals, and to shed light on the formation of SOM-mineral complexes under natural conditions: simultaneous addition of the compounds to minerals, or addition of a competitor to a mineral with pre-adsorbed compounds. We will also investigate the impact of changing redox conditions on the stability of SOM and SOM-mineral complexes. Our novel experimental results and conceptual conclusions will advance the understanding of the mechanisms of SOM-mineral complex formation, and elucidate the environmental fate of SOM and minerals.

土壤有机质是陆地生态系统中最重要的有机碳库。矿物表面对有机质的吸附是减缓有机质分解的主要稳定机制之一。有机质包括各种具有不同化学结构和性质的有机化合物，可能与矿物质相互作用。然而，这些化合物与土壤矿物的相互作用的机制，以及这些相互作用的影响，SOM和矿物复合体中的SOM和矿物的稳定性尚未阐明。在拟议的项目中，我们提出了一种新的方法，考虑SOM和矿物质的组成和结构。我们计划进行一个系统的研究，重要的SOM成分（酚酸，角质单体，肽）与土壤矿物-蒙脱石，铁和锰氧化物（水铁矿，水钠锰矿）的不同结晶度的相互作用。我们将研究快速动力学来估计矿物吸附有机质的模式和能量。我们将应用最先进的分析技术（LC/MS和XPS）来阐明矿物对不同SOM化合物的竞争或合作吸附和转化机制，以及这些相互作用对氧化物稳定性/改变的影响。我们将采用两种方案来研究矿物对有机化合物的吸附和转化，并阐明自然条件下SOM-矿物复合物的形成：同时将化合物加入矿物中，或将竞争对手加入具有预吸附化合物的矿物中。我们还将研究氧化还原条件的变化对SOM和SOM-矿物复合物的稳定性的影响。我们的新的实验结果和概念性结论将推进对有机质-矿物复合物形成机制的理解，并阐明有机质和矿物的环境命运。