Terashima Hiroshi
Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki, 305-8573, Japan.
J Colloid Interface Sci. 2002 Jan 1;245(1):81-5. doi: 10.1006/jcis.2001.7984.
A direct method is described of measuring the mass of substances dissolved from muscovite mica in water. The mica sheets are weighed by the use of a Mettler ultramicrobalance both before and after the immersion in water. The decrease in weight is regarded as identical to the dissolved mass. An analysis by ICP-AES has confirmed that the dissolution is due to an ion exchange of metal ions, mainly potassium ions. As a result of the measurement of the change in weight of mica sheets with immersion time, it has been found that it takes about 30 min to finish the dissolution. The total mass dissolved from basal plane has been determined irrespective of the difference in fraction of metal ions shared with each of the two mica surfaces obtained by cleavage along the basal plane. The measured values of the total mass differ from specimen to specimen and fall in the range from 1 to 10 mg m(-2). These values of the dissolved mass are comparable to the order of 10 monolayers of potassium ions included in basal plane. The present result suggests that internal metal ions as well as external ions contribute to the ion exchange occurring on the surface of muscovite mica.
本文描述了一种直接测量白云母在水中溶解物质质量的方法。在将云母片浸入水中之前和之后，使用梅特勒超微量天平对其进行称重。重量的减少被视为等同于溶解的质量。通过电感耦合等离子体原子发射光谱法（ICP - AES）分析证实，溶解是由于金属离子（主要是钾离子）的离子交换所致。通过测量云母片重量随浸泡时间的变化，发现溶解过程大约需要30分钟才能完成。无论沿基面解理得到的两个云母表面所共享的金属离子比例存在差异，都已确定了从基面溶解的总质量。不同样品的总质量测量值各不相同，范围在1至10 mg m(-2)之间。这些溶解质量的值与基面中包含的约10个钾离子单层的量级相当。目前的结果表明，内部金属离子以及外部离子都对白云母表面发生的离子交换有贡献。
