Imbalance between Anion and Cation Distribution at Ice Interface with Liquid Phase in Frozen Electrolyte As Evaluated by Fluorometric Measurements of pH
Imbalance between Anion and Cation Distribution at Ice Interface with Liquid Phase in Frozen Electrolyte As Evaluated by Fluorometric Measurements of pH
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DOI：
10.1021/jp5031653
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发表时间：
2014-07
影响因子：
3.7
通讯作者：
Hiroki Watanabe;T. Otsuka;M. Harada;T. Okada
中科院分区：
文献类型：
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作者：
Hiroki Watanabe;T. Otsuka;M. Harada;T. Okada
当含水电解质被冻结时，阴离子和阳离子以不同的方式分布在液相和冰相之间。这种分配不平衡通过H+和OH-转移到每个相而得到缓解，当阳离子比阴离子更好地分布在冰相中时导致液相酸化，而在相反的情况下导致碱化。在这项工作中，在液相中的pH值的变化已被精确地评价荧光比率与吡喃作为pH探针。对于冷冻的碱金属氯化物（LiCl、NaCl和KCl），由于Cl-优先分配于碱金属阳离子，液相总是通过冷冻而碱化。通过分配模型定量分析pH值的变化，其中离子在液相和冰相之间的分布由分配系数确定。由于盐的浓度（即，离子）在液相中与冰接触变得更高的冷冻进行，离子的浓度在液相中的冰。
When an aqueous electrolyte is frozen, anions and cations are distributed between liquid and ice phases in different fashions. This partition imbalance is relaxed by the transfer of H+ and OH– to each phase, resulting in the acidification of the liquid phase when the cation is better distributed in the ice phase than the anion and in the basification in the opposite situation. In this work, a pH change in the liquid phase has been precisely evaluated by fluorescence ratiometry with pyranine as the pH probe. For frozen alkali chlorides (LiCl, NaCl, and KCl), the liquid phase is always basified by freezing due to the preferential partition of Cl– over the alkali metal cations. Changes in pH are quantitatively analyzed by a partition model, in which the distribution of an ion between the liquid and ice phases is determined by the partition coefficient. Since the concentration of a salt (i.e., ions) in the liquid phase in contact with ice becomes higher as freezing proceeds, the concentration of the ions in t...