Novel experimental data on aqueous two-phase system containing PEG-6000 and Na2CO3 at TÂ =Â (293.15, 303.15 and 313.15) K

In this work liquid-liquid equilibrium (LLE) data for aqueous two-phase system (ATPS) containing polyethylene glycol 6000 (PEG-6000) and Na2CO3 were measured at T = (293.15, 303.15 and 313.15) K. Our results showed that increasing temperature expands the two-phase region; meanwhile large two-phase region was seen in this system which makes it applicable for industrial purposes. Experimental data were modeled using UNIQUAC, Extended UNIQUAC (E-UNIQUAC) and e-NRTL models to obtain binary interaction parameters. The model parameters were obtained using Shuffled Complex Evolution (SCE) optimization algorithm. The results showed that all studied models were in good agreement with the experimental data. Average deviation (%Δw) of e-NRTL, E-UNIQUAC and UNIQUAC models were 1.26, 1.37 and 3.46%, respectively. Finally in order to check the predictability of the E-UNIQUAC model, liquid-liquid equilibrium in systems containing PEG with different molecular mass (1000, 3350, 4000 and 8000) and Na2CO3 were studied; It was found that liquid-liquid equilibrium data can be predicted satisfactorily using adjusted parameters in this work.