Water activities of binary and ternary aqueous aluminium salts and poly(ethylene glycol) solutions at TÂ =Â 303.15Â K: Experimental and correlation

In this study, water activity measurements by isopiestic method have been carried out on some aqueous electrolyte solutions of both binary aqueous systems (Al(NO3)3, Al2(SO4)3 and AlCl3), ternary aqueous systems (polyethylene glycol + AlCl3 + water) and (polyethylene glycol + Al(NO3)3 + water) at T = 303.15 K. Furthermore, constant water activity curves, for ternary systems, have been plotted to study the salt effect. A relation between the salting-in effect of salt on the polymer aqueous solution and the slopes of constant water activity curves was reported. It was found that the slopes of constant water activity curves have a positive deviation from the linear isopiestic relation. In addition, the experimental water activity has been correlated successfully with some segment-based local composition models such as Wilson model, Non-Random Two Liquid (NRTL) model and the segment-based Non-Random Factor (NRF) model. The agreement between the correlation and the experimental data is good.