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Liquid-liquid equilibria (LLE) for the aqueous 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF 4 ) + kosmotropic salt (Na 3 PO 4 , Na 2 CO 3 , Na 2 SO 4 , NaH 2 PO 4 , NaCl) systems have been determined experimentally at T) 298.15 K and in part at T ) (313.15 to 333.15) K. The binodal curves are fitted to an empirical nonlinear expression developed by Merchuk, and the tie lines were described by the Othmer-Tobias and Bancroft equations. Factors affecting the binodal curves such as salts and temperature are also studied. It was found that the salting-out ability of different salts may also be related to the Gibbs energy of hydration of the ions, and the order of salting-out ability of the anions follows the Hofmerister series for the strength of the kosmotropic salts. It was also demonstrated that the two-phase area was expanded with a decrease in temperature.[Bmim]BF 4 could be recovered from aqueous solution using the aqueous two-phase system (ATPS), and the recovery efficiency could reach 98.77 %. The recovery efficiency was influenced by the concentrations of the salts and their Homeister series: Na 3 PO 4 > Na 2 CO 3 > Na 2 SO 4 > NaH 2 PO 4 > NaCl. These data are exposed to be useful for the development and design of the extraction process using ILs based on the ATPS. This proposed method also provided an effective route for the recovery of hydrophilic IL from aqueous solutions.

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Binodal data for the ethanol/1-propanol/2-propanol + ammonium sulfate + water systems were determined at 298.15 K. On the basis of an empirical equation and lever rule, the liquid−liquid equilibrium compositions of the ethanol + ammonium sulfate + water system were directly calculated by Matlab. The Othmer−Tobias equation and Bancroft equation proved the reliability of the calculation method and the corresponding tie-line data. The phase-separation abilities of hydrophilic alcohols were compared by the effective excluded volume (EEV) of salt and the binodal curves plotted in molality. The phase-separation abilities of the investigated alcohols are in the order of 1-propanol > 2-propanol > ethanol > methanol. The mechanism of phase separation and the effects of alcohols, salts, and pH values are also discussed. The results show that the increase in the amount of phase-forming substance and the decrease in pH values (from 9.03 to 3.58) are both advantageous to the formation of the aqueous two-phase system (ATPS).