عنوان مقاله [English]
The aim of this study was to investigate the distribution of lactic acid in polymer-salt aqueous two phase systems. Accordingly, four temperatures of 25, 30, 35 and 40 °C were considered and at each temperature, three different salts including sodium sulfite, disodium tartrate dihydrate and sodium dihydrogen phosphate and two different molecular masses of polyethylene glycol 30% by weight (4000 and 8000 g/mol) was tested in aqueous two-phase system. Also, the percentage of acid extraction at pH 5 to 9 and the effect of polymer concentration were investigated. The effect of polymer molecular mass, polymer concentration, salt type, salt concentration and temperature change on the extraction percentage was evaluated. It was observed that in all three systems, with increasing the molecular weight of the polymer, temperature, salt concentration, polymer concentration and pH, the extraction efficiency decreases. The optimum values of polymer molecular weight, temperature, salt concentration and pH were determined as 4000 g/mol, 25 °C, 25% by weight of sodium sulfite, disodium tartrate dihydrate and sodium dihydrogen phosphate and 5.5 to 6.5, respectively. In addition, the optimal polymer concentration was determined to be 30% by weight. Finally, the extraction values for sodium sulfite, disodium tartrate dihydrate and sodium dihydrogen phosphate were calculated to be 53.205, 50.149 and 19.549 %, respectively.