Separation of tartaric and lactic acids by means of solvent extraction

A study of the possibilities for separating tartaric and lactic acids from winery wastewaters was conducted. Some principal extractants were tested. The organic phase containing TBP, dodecane or TOA, 1-decanol, dodecane permits a selective extraction of one of the acids. The distribution coefficients of both acids with solution of tertiary amine, modifier and diluent were determined. The same organic phase was tested to remove tartaric and lactic acids from a mixture. Taking into account the selective extraction, it was concluded that the most appropriate solvent composition corresponds to 15% (v/v) TOA, 15% (v/v) 1-decanol, and 70% (v/v) dodecane. This solvent was applied in a system of countercurrent extraction which permits to separate successfully tartaric from lactic acid.