Treatment of Effluents Issued from Agro-Food Industries by Liquid− Liquid Extraction of Malic and Lactic Acids Using Tri-n-octylamine and Tri-n-butyl Phosphate.

The principal objective of this study is to develop new methods for recovery of the acids malic and lactic present in the distilling effluents of the wine industry by solvents. The information about the influence of the factors which govern thethermodynamic equilibrium of all coexistent phases in the aqueous medium of extraction is the essential step. This approach is at the base of the choice of suitable solvent taking into account its selectivity of extraction with respect to the acids lactic and malic.
The experimental study showed that the better extents are obtained when the composition of solvent corresponds to 15% (v/v) TOA, 18% (v/v) 1-decanol, and 67% (v/v) n-dodecane. The malic percentage of acid extracted is 80%, whereas that of the lactic acid is 53.6%. This last solvent exhibits an excellent extraction efficiency of the malic acid comparatively to lactic acid. The system
extractant-diluent (TBP, n-dodecane) extracts the lactic acid in a way much more selective from the solution, with a percentage of extraction exceeding 54%. Comparatively to results obtained by the ternary mixture (TOA, 1-decanol, and n-dodecane), the separation is more satisfactory using the first system.