腐殖酸与三价稀土元素的沉淀作用机制研究

Precipitation interaction mechanism of humic acid with rare earth elements.

对腐殖酸与三价稀土元素在水溶液中的结合作用进行实验研究,在宽浓度范围内探讨两者之间的络合与沉淀反应机制,考察溶液体系稳定性及其离子强度和pH值的影响.结果表明腐殖酸与稀土离子形成的配位络合物是沉淀产生的主要原因,共存体系的稳定性明显受到离子强度和pH值影响.腐殖酸和稀土元素通过共沉淀从溶液中去除,在作用机制上表现为离子交换、配位络合和共沉淀等多种形式.

Interactions of humic acid with trivalent rare earth ions (REE^(3+)) in solution were examined to study the mechanisms of complexation and precipitation reactions, and the effects of ionic strength and pH on the stability of solution systems were investigated. The experimental results indicated that the formation of complexation products of humic acid with REE^(3+) is the main cause of precipitation, and the stability of coexisting solution systems is affected evidently by the ionic strength and pH. The humic acid and rare earth elements can be removed from the solution by the coprecipitation in which the ion exchange, complexation and coprecipitation are the most important interaction mechanism.