Andersson Maria E, Gårdfeldt Katarina, Wängberg Ingvar, Strömberg Dan
Department of Chemistry, Göteborg University, Göteborg, Sweden.
Chemosphere. 2008 Sep;73(4):587-92. doi: 10.1016/j.chemosphere.2008.05.067. Epub 2008 Jul 23.
The assessment of the global mercury cycle involves estimations of the evasion of mercury form oceanic waters. In such estimations Henry's law constant is often used. In this study the Henry's law constant for elemental mercury has been re-determined in MQ water and artificial sea water. Moreover, for the first time it has been determined for 1.5M sodium chloride (NaCl) solution which is of relevance for modeling of atmospheric waters at coastal locations. For all solutions, experiments has been conducted at five different temperatures between 278 and 308K, using a novel technique, for mercury, based on direct measurements of the portioning of mercury between the aqueous and gaseous phase. Elemental mercury was extracted from the water column and the logarithm of the mass of extracted mercury was plotted against time. A dimensionless Henry's law constant, defined as: [see text] was obtained from the slope of the curve. Almost no difference was observed in the values comparing the Milli-Q water and artificial sea water, however for the 1.5M NaCl solution a salting-out effect was seen, i.e. the solubility of mercury in the water phase decreased. The decreased solubility will generate an increase in the value of Henry's law constant.
全球汞循环的评估涉及对汞从海水中逸出量的估算。在这类估算中，亨利定律常数常被使用。在本研究中，已在超纯水和人工海水中重新测定了元素汞的亨利定律常数。此外，首次针对与沿海地区大气水建模相关的1.5M氯化钠（NaCl）溶液测定了该常数。对于所有溶液，使用一种基于直接测量汞在水相和气相间分配的新技术，在278至308K的五个不同温度下进行了实验。从水柱中提取元素汞，并将提取的汞质量的对数与时间作图。从曲线斜率获得了一个无量纲的亨利定律常数，定义为：[见原文]。比较超纯水和人工海水时，未观察到值有几乎差异，然而对于1.5M NaCl溶液，出现了盐析效应，即汞在水相中的溶解度降低。溶解度降低会导致亨利定律常数的值增加。
