SURFACE-TENSION AND BUBBLE COALESCENCE PHENOMENA OF AQUEOUS-SOLUTIONSOF ELECTROLYTES

The inhibition of bubble coalescence by electrolytes beyond a critical transition concentration has been assessed by the relationship betwee n transition concentration and surface tension gradients of electrolyt es (d(Delta gamma)/dc) and gas solubility. The correlation between tra nsition concentration and [d(Delta gamma)/dc](-2) was mediocre (0.74), suggesting that the Gibbs-Marangoni effect cannot fully account for i nhibition of bubble coalescence. Preliminary bubbling experiments on m ixed electrolytes supported this conclusion. A much better correlation was found between the transition concentration and gas solubility (re presented by the exponential decay coefficient of O-2 solubility with increasing electrolyte concentration). Hence, the inhibition of bubble coalescence may be linked with the decreased dissolved gas concentrat ion in the electrolyte solution.