腐殖酸与稀土元素的作用及体系稳定性

Binding capacity and stability of humic acid with rare earth elements in solution.

用稀土元素（Ｌａ３＋，Ｃｅ３＋，Ｈｏ３＋，Ｙｂ３＋）标准溶液对湖泊沉积物腐殖酸进行非连续滴定，研究二者之间的络合反应能力及其结合产物在水溶液体系的稳定性。结果表明，腐殖酸结构中的活性点位在与三价稀土离子作用时表现出两种不同类型，在机制上采取两级络合反应。体系中沉淀生成与否主要取决于腐殖酸对稀土离子的容纳能力。

Dissolved humic acid extracted from lake sediment was titrated discontineously with the standard solutions of rare earth elements (La 3+ , Ce 3+ , Ho 3+ , Yb 3+ ) to investigate the complexation capacity and the stability of humic acid and REE-humate in solution. Apparently there are two types of binding sites in the functional groups of humic acid, which take two steps of complexation reations in mechanism. The occuring of precipitation is mainly dependent on the holding capacity to rare earth element by humic acid.