Abstract In this work, thermodynamic properties of unsaturated solutions of (CuSO4 + PEG 2000 + H2O) system at (303.15, 313.15, 323.15 and 333.15) K were studied. The concentration range of the solutions was from 0.01 to 0.05 mass fraction of CuSO4 and from 0.15 to 0.3 mass fraction of poly(ethylene glycol) with an average molar mass of 2000 g/mol. Water activities were correlated with the modified Pitzer model, obtaining a good agreement between the experimental and correlated data. In addition, water activities predictions for the (CuSO4 + PEG 4000 + H2O) and (CuSO4 + PEG 2000 + H2O) systems were performed with the modified Pitzer and extended UNIQUAC models, respectively, showing that both thermodynamic models operate independently of the molar mass of the polymer used. The effect of the cations on the water activities of different (Salt + PEG 4000) systems was evaluated, showing a close relation with the Molar Gibbs Energies of Hydration of the respective cations. The salting effect and Gibbs Energy change (ΔG) of different ternary systems showed that a salting-out effect occurs in all the studied systems.

中文翻译：

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{CuSO4 + 聚（乙二醇）+ H2O} 系统在 303.15 至 333.15 K 温度范围内的水活度测量和建模

摘要 本文研究了(CuSO4 + PEG 2000 + H2O) 体系不饱和溶液在(303.15, 313.15, 323.15 和333.15) K 下的热力学性质。溶液的浓度范围为 0.01 至 0.05 质量分数的 CuSO4 和 0.15 至 0.3 质量分数的聚（乙二醇），平均摩尔质量为 2000 g/mol。水分活度与修改后的 Pitzer 模型相关，在实验数据和相关数据之间获得了良好的一致性。此外，对 (CuSO4 + PEG 4000 + H2O) 和 (CuSO4 + PEG 2000 + H2O) 系统的水分活度预测分别使用改进的 Pitzer 和扩展的 UNIQUAC 模型进行，表明这两种热力学模型均独立于摩尔质量运行所使用的聚合物。评估了阳离子对不同（盐 + PEG 4000）系统水活度的影响，显示出与各个阳离子的摩尔吉布斯水合能密切相关。不同三元体系的盐析效应和吉布斯能量变化（ΔG）表明，所有研究体系都发生盐析效应。