Modeling of ionic equilibria of trace metals(Cu~(2+),Zn~(2+),Cd~(2+))in concentrated aqueous electrolyte solutions at 25 deg C

摘要

This work presents a model of activity coefficients and a database for ionic equilibria of Cu~(2+),Zn~(2+),and Cd~(2+)in(H~+,Na~+,K~+,Mg~(2+),Ca~(2+))(OH~-,Cl~-,NO_3~-,ClO_4~-,HSO_4~-,SO_4~(2-),HCO_3~-,CO_3~(2-))aqueous media valid up to 6-12 m ionic strength.The activity coefficient of a dissolved species is represented by empirical equation ln gamma_i= -(A_(gamma)/2)z_i~2(I - Iexp(-8I~(0.5)))~(1/3)+ sum b_(ij)m_j,where A_(gamma)is Debye-Huckel constant(1.17 at 25 deg C),gamma_i and z_i are activity coefficient and charge of a dissolved species i,I is molal ionic strength,b_(ij)is model parameter,and m_j is molal concentration of dissolved species.The model is applicable to the modeling of ionic equilibria,as well as to simulation of solubility of salts in mixed electrolyte solutions.