Simultaneous Presence of Diverse Molecular Patterns in Humic Substances in Solution

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• 作者：Roberto Baigorri ; Marta Fuentes ; Gustavo Gonzá ; lez-Gaitano ; Jose M Garcí ; a-Mina
• 刊名：Journal of Physical Chemistry B
• 出版年：2007
• 出版时间：September 6, 2007
• 年：2007
• 卷：111
• 期：35
• 页码：10577 - 10582
• 全文大小：399K
• 年卷期：v.111,no.35(September 6, 2007)
• ISSN：1520-5207

文摘

The chemical and structural nature of humic substances (HS) is the object of an intense debate in the literatureinvolving two main theoretical positions: the classical view defending the macromolecular pattern, and thenew, more recent, view proposing a supramolecular pattern. In this study, we observe that both molecularpatterns are present in different whole humic systems in solution. We also identify these molecular patternswith a specific fraction of HS. Thus, the HS family formed by the gray humic acids studied presented a clearmacromolecular pattern, whereas the HS family formed by the fulvic acids studied presented the coexistenceof supramolecular assemblies and individual molecules. The third HS family studied, the brown humic acids,presented both the macromolecular pattern and the supramolecular pattern. We also find that molecularaggregation-disaggregation has a strong influence in the fluorescence pattern of HS, thus indicating that thecurrent concepts of HS structure derived from fluorescence studies need revision.