Fe^(2+)/Mn^(2+)/Zn^(2+)在NH_3-H_2O系中的溶解度

Solubility of Fe^(2+)/Mn^(2+)/Zn^(2+) in NH_3-H_2O System

通过对Fe^(2+),Mn^(2+),Zn^(2+)-NH_3-H_2O系的热力学分析计算,利用Newton-Raphson方法求解多元非线性方程组,绘出这3种金属离子在不同溶液pH值和不同总氨浓度条件下的log[Me]_T-pH曲线。溶液中没有NH_3存在或[NH]_T很低时,Fe,Mn,Zn的溶解度都随pH增大先减小,达到最小值后,又增加。随NH_3浓度增加,Fe,Mn,Zn的溶解度随之增大。3种离子和氨的络合能力不尽相同,锌与氨的络合能力最强,铁次之,而锰最弱。

The log[Me]T- pH curves in the Fe2+ -Mn2+-Zn2+-HN3-H2O system under various pH and total ammonia concentration are presented by thermodynamic analysis and calculation, and solving the group of nonlinear equations with Newton-Raphson Method. The solubilities of Fe, Mn and Zn are initially reduced with the pH increase of solution, and increased after the minimum is reached. And the solubilities of Fe, Mn and Zn are increased with the increase of the total ammonia concentration. For the complexity with ammonia, zinc is the strongest, then is the ferrous ion, and the manganese is the last one.