Correlations between the maximum parameters of DLVO interaction energy curves and the electrolyte concentration

In a previous work (J. Mol. Struct.: THEOCHEM, 769,165 (2006)) we have addressed a detailed study of the set of parameters that must be used within the scope of DLVO theory for a calculation of stability ratios of colloidal particles through an approximate expression. The approximate form of the equation that defines of the stability ratio W, derived in the mentioned work above, requires as much of the knowledge of the maximum of interaction potential energy between particles, V_max, and its position //max, as well as the absolute value of the second derivative of interaction potential energy with respect to position at H_max, \V"(H_max)\. Since these maximum parameters come determined for a concentration defined of the electrolyte is possible to establish the dependence of those with such concentration by letting the fitting constants depend on superficial potential, Hamaker constant and size of the particles. In this work we presented correlations between the maximum parameters (V_max and H _max) and the univalente symmetrical electrolyte concentration for a system of two spherical colloidal particles with constant of Hamaker, superficial potential and size well-known. The curves of energy of interaction as a function of the distance of separation of particle surface were obtained for two models of DLVO potentials. For appropriate conditions, the reported correlations give equations that are independent of DLVO potential model and can be used to evaluate the approximated stability ratio for systems of identical particles (homocoagulation) as well as the particle systems with different superficial potentials (heterocoagulation). The approximate stability ratios calculated with these correlations can be determined with an error smaller than 5% compared to obtain from the DLVO potential curves.