RECOVERY OF TARTARIC AND MALIC-ACIDS FROM DILUTE AQUEOUS EFFLUENTS BY SOLVENT-EXTRACTION TECHNIQUE

Solvent extraction deserves consideration for the recovery of carboxylic acids from wastewater in order to clean up industrial effluents. Tartaric and malic acids are present in low concentration in the effluents of distilleries producing grape sugar. The separation of these acids from dilute aqueous solutions by the technique of dissociation extraction employing respectively tributylphosphate dissolved in dodecane and triisooctylamine (tris-(6-methylheptyl)-amine) dissolved in 1-octanol as solvents was explored in this study. With a solvent ratio of 0.5 and a solvent containing 0-6 mole of triisooctylamine per dm3 of the triisooctylamine + 1-octanol mixture, the best percentages of malic and tartaric acids recovered were respectively 92 mass% and 99 mass% relative to the quantities of these acids present in the initial aqueous solutions.