pH值与水的表面张力。

pH and the surface tension of water.

作者信息

Beattie James K, Djerdjev Alex M, Gray-Weale Angus, Kallay Nikola, Lützenkirchen Johannes, Preočanin Tajana, Selmani Atiđa

机构信息

School of Chemistry, University of Sydney, NSW 2006, Australia.

出版信息

J Colloid Interface Sci. 2014 May 15;422:54-7. doi: 10.1016/j.jcis.2014.02.003. Epub 2014 Feb 22.

DOI:10.1016/j.jcis.2014.02.003

PMID:24655828

Abstract

Despite the strong adsorption of hydroxide ions, the surface tension of water is almost independent of pH between pH 1 and 13 when the pH is adjusted by addition of HCl or NaOH. This is consistent with the Gibbs adsorption isotherm which measures the surface excess of all species in the double layer, if hydronium ions and hydroxide ions are adsorbed and sodium and chloride ions are not. The surface tension becomes pH dependent around pH 7 in millimolar NaCl or KCl solutions, for now sodium ions can replace hydronium ions as counterions to the adsorbed hydroxide ions.

摘要

尽管氢氧根离子有很强的吸附作用，但当通过添加HCl或NaOH来调节pH值时，在pH 1至13之间，水的表面张力几乎与pH无关。如果水合氢离子和氢氧根离子被吸附，而钠离子和氯离子不被吸附，这与测量双层中所有物种表面过剩量的吉布斯吸附等温线是一致的。在毫摩尔浓度的NaCl或KCl溶液中，表面张力在pH约为7时开始与pH有关，因为此时钠离子可以取代水合氢离子作为被吸附氢氧根离子的抗衡离子。