Recovery of lactic and tartaric acid from dilute aqueous effluents by liquid extraction

In order to reduce environmental pollution, the elimination of weak organic acids from agro-industrial wastewater is a difficult matter when the solutes are very soluble in the water phase and are furthermore insufficiently volatile for distillation. In this case, it is economically preferable to remove the organic acids by a solvent extraction process. In this study, the possibilities of recovery and separation of tartaric and lactic acids from dilute aqueous solution were explored by the technique of dissociation extraction using respectively the solvents tributylphosphate + Dodecane, triisooctylamine + 1-Octanol and 1-Decanol. Several experiments were carried out successively by single contact in one extraction stage and then by multiple contact in a continuous countercurrent MORRIS extractor hence to improve the selectivity of the separation and the yield of the operation.