Thermogravimetric analysis of the salts and metal complexes of a soil fulvic acid
Thermogravimetric analysis of the salts and metal complexes of a soil fulvic acid
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DOI：
10.1016/0016-7037(67)90094-4
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发表时间：
1967
影响因子：
5
通讯作者：
M. Schnitzer;I. Hoffman
中科院分区：
文献类型：
--
作者：
M. Schnitzer;I. Hoffman
研究了一种水溶性土壤腐殖质化合物灰腐酸与16种不同的一价、二价和三价金属离子的盐及其配合物。每种盐和络合物都用化学和红外方法进行了表征，更详细地说，用热重法进行了表征。未处理的黄腐酸的DTG曲线在420°C处有一个峰值，当黄腐酸与一价阳离子反应时，DTG曲线的温度升高，而当黄腐酸与二价和三价金属离子络合时，DTG曲线的温度降低。黄腐酸的Na-、K-和li -盐在温度为> ~ 700℃时转化为无机碳酸盐，而黄腐酸的nh4盐在温度为> ~ 550℃时形成碳酸盐。金属-黄腐酸配合物的稳定性，通过离子交换平衡法测量，通常与它们的热稳定性成反比，如主要的DTG峰所示。
Salts and complexes of sixteen different mono-, di- and trivalent metal ions with a Podzol fulvic acid, a water-soluble soil humic compound, were prepared. Each salt and complex was characterized by chemical and i.r. methods and, in more detail, by thermogravimetry. The DTG curve of untreated fulvic acid exhibited a major peak with a maximum at 420°C which shifted to considerably higher temperatures when the fulvic acid had reacted with monovalent cations, but to lower temperatures when fulvic acid had complexed with di- and trivalent metal ions. The Na-, K- and Li-salts of fulvic acid appeared to be converted to inorganic carbonates at temperatures >700°C, whereas the NH4-salt of fulvic acid formed the carbonate at >550°C. The stabilities of the metal—fulvic acid complexes, as measured by an ion-exchange equilibrium method, appeared in general to be inversely related to their thermal stabilities as indicated by major DTG peaks.