Removal of low molecular organic acids from aqueous solutions with reactive extraction

This paper presents investigation on removal of low molecular organic acids (acetic, lactic, succinic and fumaric) from aqueous solutions with reactive extraction. The results specifically show that the extraction efficiency of acids depends on the type of extractant, diluents of the organic phase and the initial pH of the aqueous phase. It is possible to separate succinic or fumaric from lactic and acetic acids with high selectivity with the use of TOA and Aliquat 336, respectively. Increasing the pH of the aqueous phase results in a reduction of fumaric acid extraction efficiency with solvating extractants. This can be explained by the decreasing share of acidic form, whose extraction is favored by these extractants. Efficient extraction of both fumaric acid and fumarate using Aliquat 336 can be explained by the ionic structure of the quaternary ammonium salt, capable of transporting both forms of the acid.