화학공학소재연구정보센터
Fluid Phase Equilibria, Vol.154, No.1, 109-122, 1999
Modeling of liquid-liquid equilibrium of polyethylene glycol salt aqueous two-phase systems - the effect of partial dissociation of the salt
The modified NRTL model proposed in the previous paper [Y.-T., Wu, D.-Q, Lin, Z.-Q. Zhu, L.-H. Mel, Fluid Phase Equilibria 124 (1996) 67-79.] is further extended to include the effect of partial dissociation of salts in polyethylene glycol (PEG)-salt aqueous two-phase systems (ATPS), and is used to calculate the Liquid-liquid equilibrium phase diagrams such as PEG-(NH4)(2)SO4 and PEG-MgSO4 ATPS. The phase diagrams of PEG-uni-bivalent salt ATPS can be correctly represented in the cases of both complete dissociation and partial dissociation of the salt, while those of PEG-MgSO4 ATPS can only be described in the case of partial dissociation of the salt, The analysis shows that the salts may have different existing states in the ATPS. The effect of partial dissociation of the salts on the phase diagrams should be considered, especially for systems such as PEG-MgSO4 ATPS.