Journal of Physical Chemistry B, Vol.111, No.37, 10985-10991, 2007
Homogeneous nucleation temperatures in aqueous mixed salt solutions
This is the first report on the measurement of homogeneous nucleation temperature, T-H, in the presence of aqueous mixed salt systems of varying compositions and ionic strengths. The T-H,T-m (T-H value in aqueous mixed salt system) data for these systems have been analyzed in terms of a simple empirical equation. The T-H.m. values in simple aqueous mixed salts like NaCl-KCl can be approximated by linear summation of the products of ionic strength fraction and the T-H values of pure salt solutions at the same ionic strength as that of the mixture. The empirical parameter, q(0), indicating ionic interaction is related to the viscosity B-coefficients. The T-H.m data, though correlated on the basis of the B-coefficients also depends upon the mixing of two ions of like charges. Further, a linear correlation exists between the q(0) parameter and self-diffusion coefficient, D-0, of the ionic solute. The q(0) parameter is also well correlated with the rotational correlation time, T-c(h)/T-c(0) of the ionic species involved in the mixtures. It is possible to compute T-H,T-m for the salt mixtures with no common ions from the knowledge of the T-H,T-m values of the salt mixtures with common ions.