Concentrated aqueous electrolyte solutions: Analytical equations for humidity-concentration dependence

摘要

The Henry's law, Freundlich, and Dubinin-Astakhov, Brunauer-Emmett-Teller equations, and a new modification of the BET equation are used for the thermodynamic analysis of the activity of water over wide ranges of temperature (260-600 K) and water content (mole fraction 0.3-0.8) in concentrated aqueous solutions of electrolytes. The solutes considered are H2SO4, CaCl2, LiBr, LiCl, LiI, MgCl2, and NaOH in bulk solutions, and CaCl2 and LiBr dispersed in porous matrixes. The generalized Henry's law equation is found to afford a correct extrapolation of bulk solution properties measured at low and moderate salt concentrations to the region of low water content. The suggested modification of the BET equation as well as the Dubinin-Astakhov equation give an accurate (relative error less than 1%) description of literature data on the humidity-concentration dependence and can be used for the reliable prediction of this dependence in the region of intermediate conditions. [References: 35]