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首页> 外文期刊>Environmental Science & Technology >Spatial Associations and Chemical Composition of Organic Carbon Sequestered in Fe, Ca, and Organic Carbon Ternary Systems
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Spatial Associations and Chemical Composition of Organic Carbon Sequestered in Fe, Ca, and Organic Carbon Ternary Systems

机译：Fe，Ca和有机碳三元系中有机碳的空间缔合和化学组成

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摘要

Organo-mineral associations of organic carbon (OC) with iron (Fe) oxides play a major role in environmental OC sequestration, a process crucial to mitigating climate change. Calcium has been found to have high coassociation with OC in soils containing high Fe content, increase OC sorption extent to poorly crystalline Fe oxides, and has long been suspected to form bridging complexes with Fe and OC. Due to the growing realization that Ca may be an important component of C cycling, we launched a scanning transmission X-ray microscopy (STXM) investigation, paired with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, in order to spatially resolve Fe, Ca, and OC relationships and probe the effect of Ca on sorbed OC speciation. We performed STXM-NEXAFS analysis on 2-line ferrihydrite reacted with leaf litter-extractable dissolved OC and citric acid in the absence and presence of Ca. Organic carbon was found to highly associate with Ca (R ~(2) = 0.91). Carboxylic acid moieties were dominantly sequestered; however, Ca facilitated the additional sequestration of aromatic and phenolic moieties. Also, C NEXAFS revealed polyvalent metal ion complexation. Our results provide evidence for the presence of Fe–Ca–OC ternary complexation, which has the potential to significantly impact how organo-mineral associations are modeled.
机译：有机碳（OC）与氧化铁（Fe）的有机-矿物缔合在环境OC隔离中起着重要作用，该过程对于缓解气候变化至关重要。在高铁含量的土壤中，钙与OC具有很高的缔合作用，增加了OC对弱结晶的Fe氧化物的吸收程度，并且长期以来一直被怀疑与Fe和OC形成桥连络合物。由于人们逐渐认识到Ca可能是C循环的重要组成部分，我们开展了扫描透射X射线显微镜（STXM）研究，并与近边缘X射线吸收精细结构（NEXAFS）光谱配对，以便在空间上解决Fe，Ca和OC关系，并探讨Ca对吸收的OC形态的影响。我们在不存在和存在Ca的情况下，对与叶凋落物提取的溶解OC和柠檬酸反应的2线亚铁水合物进行了STXM-NEXAFS分析。发现有机碳与Ca高度缔合（R 2（i）＝ 0.91）。羧酸部分被隔离。但是，Ca促进了芳香族和酚类部分的进一步螯合。另外，C NEXAFS显示多价金属离子络合。我们的结果提供了Fe-Ca-OC三元络合物存在的证据，这可能会显着影响有机-矿物缔合的建模方式。

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  • 来源
    《Environmental Science & Technology》 |2018年第12期|6936-6944|共9页
  • 作者

    Tyler D. Sowers; Dinesh Adhikari; Jian Wang; Yu Yang; Donald L. Sparks;

  • 作者单位

    Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware, Newark, Delaware 19716, United States;

    Department of Civil and Environmental Engineering, University of Nevada, Reno, Nevada 89557 United States;

    Canadian Light Source Inc., University of Saskatchewan, Saskatoon, Saskatchewan S7N 2 V3, Canada;

    Department of Civil and Environmental Engineering, University of Nevada, Reno, Nevada 89557 United States;

    Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware, Newark, Delaware 19716, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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