SALT EFFECTS IN EXTRACTION OF ETHANOL, 1-BUTANOL AND ACETONE FROM AQUEOUS-SOLUTIONS

Experimental studies were performed to assess the effect of salt addit ion on the extraction of 1-butanol, ethanol and acetone from dilute aq ueous solutions using cyclopentanol, n-valeraldehyde, tert-amyl alcoho l, and Adol 85NF as extractants. The liquid-liquid partitioning was ex amined for a few strong electrolytes in a broad range of concentration s. Results demonstrate that the distribution coefficient and selectivi ty in systems with reduced water activity resulting from salt addition were markedly increased. These observations can be qualitatively expl ained on the basis of the hydration theory. It was also determined tha t strong electrolytes added to the aqueous feed reduced extractant sol ubility in the aqueous phase, thus contributing to lower solvent losse s. The results showed that the extraction efficiency was not significa ntly affected by increasing salt content beyond a level that reduces t he water activity to a value of 0.92.