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电位法测量了碱金属离子由水相到TBP(磷酸三丁酯)-CH_3OH混合溶剂相的标准迁移自由能⊿G_t~0研究了溶剂化作用同PVC膜对金属离子选择性的关系。碱金属离子的⊿G_t~0随着TBP在混合溶剂中含量的增加而增大。⊿G_t~0还随着离子半径的增大而增大,这同TBP-PVC膜对碱金属离子的选择性次序相一致;而与四苯硼酸盐-TBP-PVC膜对碱金属离子的选择性次序不完全相同。说明了TBP为溶剂的四苯硼酸盐膜对金属离子的选择性除了同溶剂化作用有关外,还同膜相和水相中离子的交换反应常数等因素相关。
Potential method was used to measure the standard free energy of migration of alkali metal ions from aqueous phase to TBP (TBP) -CH_3OH mixed solvent phase. The relationship between solvation and the selectivity of PVC membrane to metal ions was investigated.碱G_t ~ 0 of alkali metal ions increased with the content of TBP in the mixed solvent. ⊿G_t ~ 0 also increases with the increase of ionic radius, which is consistent with the selective order of TBP-PVC membrane to alkali metal ions; while with tetraphenylborate -TBP-PVC membrane of alkali metal ions Selective order is not exactly the same. It is shown that the selectivity of tetraphenylborate membranes with TBP as solvent for metal ions is related to the solvatisation and the exchange reaction constant of ions in the membrane phase and aqueous phase.