A KINETIC MODEL FOR CRYSTAL-GROWTH FROM AQUEOUS-SOLUTION IN THE PRESENCE OF IMPURITY
A KINETIC MODEL FOR CRYSTAL-GROWTH FROM AQUEOUS-SOLUTION IN THE PRESENCE OF IMPURITY
复制标题
DOI：
10.1016/0022-0248(95)00128-x
复制
发表时间：
1995-07-01
影响因子：
1.8
通讯作者：
MULLIN, JW
中科院分区：
文献类型：
--
作者：
KUBOTA, N;MULLIN, JW
本文提出了一个描述水溶液中晶体生长速率随杂质浓度变化的数学模型。该模型假设的步骤速度线性下降，增加表面覆盖率（θ（eq））的杂质吸附在生长的晶体，并引入一个比例常数α考虑杂质的有效性。当α> 1时，步进速度停止在Theta（eq）< 1（吸附活性位点的不完全覆盖）。在alpha = 1的情况下，速度仅在Theta（eq）= 1时达到零，并且对于alpha < 1，即使在Theta（eq）= 1（完全覆盖）时，速度也不会变为零，而是接近极限值。利用朗缪尔吸附等温线将相对阶跃速度与溶液中杂质浓度联系起来。三个典型的情况下，在文献中报道，每个以前解释了不同的模型，被证明是令人满意的描述与这个新的单一模型。α值受立体化学因素的影响而变化，并随过饱和度的增加而减小。过饱和效应的Cabrera Vermilyea模型的帮助下解释。
A mathematical model describing crystal growth rates from aqueous solution as a function of impurity concentration is presented. The model assumes that the step velocity decreases linearly with increasing surface coverage (Theta(eq)) by impurities adsorbed on the growing crystal, and a proportionality constant alpha is introduced to take into account the effectiveness of the impurity. When alpha > 1, the step velocity is stopped at Theta(eq) < 1 (incomplete coverage of the active sites for adsorption). In the case of alpha = 1, the velocity reaches zero just at Theta(eq) = 1, and for alpha < 1, it never becomes zero even at Theta(eq) = 1 (complete coverage) but approaches a limiting value. The Langmuir adsorption isotherm is used to relate the relative step velocity with the impurity concentration in solution. Three typical cases reported in the literature, each previously explained with a different model, are shown to be described satisfactorily with this new single model. The value of alpha is changed by stereochemical factors and decreases as the supersaturation is increased. The supersaturation effect is explained with the aid of the Cabrera-Vermilyea model.