Otsu Emi, Etou Mayumi, Ohashi Hironori, Nishida Ikuko, Bai Shuquin, Okaue Yoshihiro, Yokoyama Takushi
Department of Chemistry, Faculty of Science, Kyushu University, Higashi, Fukuoka, Japan.
Anal Sci. 2013;29(3):333-7. doi: 10.2116/analsci.29.333.
In order to estimate the absolute size distribution of polysilicic acid particles in geothermal waters, the distribution coefficient (K(av)) of gel permeation chromatography (GPC) for polysilicic acid particles and the hydrodynamic radius for the same polysilicic acid particles from Dynamic Light Scattering (DLS) are combined to quantify the particle size. From the combination, a quantitative relationship between the K(av) from GPC and the hydrodynamic radius for polysilicic acid from DLS was built up. Using this relationship, the change in particle size of polysilicic acid formed during the polymerization of silicic acid at pH 8 and 9 (initial silicic acid concentration: 800 ppm as SiO2) was examined. The result showed that polysilicic acid grew to 500 and 1000 nm by 5 h at pH 9 and 8, respectively. It was found that aluminum affects the growth of polysilicic acid particles, and that the effect depends on the pH. The proposed method in this study has been proved to be valid to measure the size of polysilicic acid during the polymerization of silicic acid in solutions with relatively low silicic acid concentration, such as geothermal water.
为了估算地热水中聚硅酸颗粒的绝对尺寸分布，将凝胶渗透色谱法（GPC）对聚硅酸颗粒的分配系数（K(av)）与动态光散射法（DLS）测得的相同聚硅酸颗粒的流体力学半径相结合来量化粒径。通过这种结合，建立了GPC的K(av)与DLS测得的聚硅酸流体力学半径之间的定量关系。利用该关系，研究了在pH值为8和9（初始硅酸浓度：以SiO2计为800 ppm）时硅酸聚合过程中形成的聚硅酸粒径的变化。结果表明，在pH值为9和8时，聚硅酸分别在5小时内增长到500和1000 nm。发现铝会影响聚硅酸颗粒的生长，且这种影响取决于pH值。本研究中提出的方法已被证明在测量硅酸浓度相对较低的溶液（如地热水）中硅酸聚合过程中聚硅酸的尺寸时是有效的。
