Role of CaCO(3)° Neutral Pair in Calcium Carbonate Crystallization.
Role of CaCO(3)° Neutral Pair in Calcium Carbonate Crystallization.
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DOI：
10.1021/acs.cgd.6b00276
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发表时间：
2016-08-03
影响因子：
3.8
通讯作者：
García-Ruiz JM
中科院分区：
文献类型：
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作者：
Genovese D;Montalti M;Otálora F;Gómez-Morales J;Sancho-Tomás M;Falini G;García-Ruiz JM
在从过饱和溶液到晶体形成的过程中，进入晶相核心并维持其生长的单元的分子结构是一个基本问题。用荧光染料记录了在CaCl2和NaHCO3反扩散结晶CaCO3的凝胶中pH值随时间的变化。使用化学形态代码(Phreeqc)也计算得到了相同的pH-时空分布图。利用该模型得到的数据，我们研究了结晶过程中涉及的单一物种(离子和离子对)活性的时空演化。我们的综合结果表明，无论从溶液到晶体的途径是什么，中性对CaCO3°都是CaCO3沉淀体系中的关键物种。进行了碳酸钙沉淀的时间/空间分辨实验，以原位跟踪过程中pH的变化。这一实验数据与同时模拟溶液形态、多组分扩散和沉淀的模拟数据的比较，对CaCO3°中性对在碳酸钙沉淀中的作用具有启发意义。
The molecular structure of the units that get incorporated into the nuclei of the crystalline phase and sustain their growth is a fundamental issue in the pathway from a supersaturated solution to the formation of crystals. Using a fluorescent dye we have recorded the variation of the pH value in time along a gel where CaCl2 and NaHCO3 counter-diffuse to crystallize CaCO3. The same pH–space–time distribution maps were also computationally obtained using a chemical speciation code (phreeqc). Using data arising from this model we investigated the space-time evolution of the activity of the single species (ions and ion pairs) involved in the crystallization process. Our combined results suggest that, whatever the pathway from solution to crystals, the neutral pair CaCO3° is a key species in the CaCO3 precipitation system. Time/space-resolved experiments of calcium carbonate precipitation have been run to follow in situ the evolution of pH during the process. Comparisons of this experimental data with simulations simultaneously modeling solution speciation, multicomponent diffusion, and precipitation is enlightening about the role of CaCO3° neutral pair on calcium carbonate precipitation.