Ni^(2+)-H_2O系羟合配离子的配位平衡

Equilibrium of Hydroxyl Complex Ions in Ni^(2+)-H_2O System

根据配位化学热力学平衡原理,绘制Ni2+-H2O系配合离子浓度pc-pH图、镍羟合配离子分率αn-pH图及Ni(OH)2条件溶度积pPS-pH图。pc-pH图描述了Ni(OH)2(固)溶解平衡时,镍的总离子平衡浓度与pH关系,pH为10~11时Ni(OH)2的溶解度最小。αn-pH图指出了各种羟合配离子分率与pH关系,每种羟合配离子都对应有其存在的最佳pH范围。Ni(OH)2(固)的条件溶度积pPS-pH图表明pH在9~11范围内Ni(OH)2(固)的条件溶度积最小。研究结果可为中和水解法去除废水中镍等技术提供理论依据。

The diagrams for the concentration of complex ions pc-pH,the ratio of nickel hydroxy complex ions αn-pH,conditional solubility product of Ni（OH）2 to pH in Ni^2＋-H2O system,are drawn,respectively,based on the thermodynamic equilibrium principle of complex chemistry.The relationship between the equilibrium concentration of total nickel ions and pH is shown in Ni^2＋-H2O system,when dissolution of Ni（OH）2 is in equilibrium.The solubility of Ni（OH）2 is least at pH range of 10 to 11.The diagram for αn-pH shows that each hydroxy complex ion existed in the system is dependent upon an optimized pH value. The diagram for the conditional solubility product pPs-pH indicates that the PPs reaches minimum at the pH range of 9 to 11. The results can provide a theoretical basis for the technology on removal of nickel ion from the wastewater by neutralized hydroxylation method.