Thermodynamic Descriptors of Sensible Heat Driven Liquid-Liquid Phase Separation
Thermodynamic Descriptors of Sensible Heat Driven Liquid-Liquid Phase Separation
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DOI：
10.1016/j.molliq.2022.119440
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发表时间：
2022-05
影响因子：
6
通讯作者：
Sidharth Sanadhya;Zachary D. Tucker;Eva M. Gulotty;William Boggess;B. Ashfeld;S. Moghaddam
中科院分区：
文献类型：
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作者：
Sidharth Sanadhya;Zachary D. Tucker;Eva M. Gulotty;William Boggess;B. Ashfeld;S. Moghaddam
通过显热将均相溶液分离成其组成的液体，就不需要汽化/蒸馏和相变潜热。因此，在许多涉及分离可混溶液体的应用中，它可以实现更节能的替代循环。这可以通过利用较低和较高临界溶液温度(LCST/UCST)驱动的相分离来实现。这项研究确定了用于预测离子液体(IL)-水/醇(溶剂)溶液的LCST/UCST的热力学描述符，从而提供了对多组分溶液与温度和浓度相关的相容的潜在能量学的基本见解。对50种溶液的过量Gibbs能量分析表明，溶剂(水/醇)在相分离中起着关键作用，并且在LCST和UCST区域表现出截然不同的过剩Gibbs能量贡献。此外，通过对标度吉布斯能的分析，阐明了相分离的能量学，并从热力学上区分了LCST和UCST。因此，我们引入了溶剂折合活度系数(RAC)来成功地预测相分离行为，而不需要计算Gibbs能量函数，从而节省了大量的计算时间。
Separation of a homogeneous solution into its constituent liquids through sensible heating obviates the need for vaporization/distillation and the associated latent heat of phase change. Therefore, it could enable alternative more energy efficient cycles in many applications that involve the separation of miscible liquids. This can be achieved by utilizing Lower and Upper Critical Solution Temperature (LCST/UCST) driven phase separation. This study identifies the thermodynamic descriptors for predicting LCST/UCST exhibiting ionic liquid (IL) - water/alcohol (solvent) solutions, and therefore provides a fundamental insight into the underlying energetics responsible for temperature and concentration dependent miscibility of multicomponent solutions. Excess Gibbs energy analysis of 50 solutions revealed that the solvent (water/alcohol) played a pivotal role in phase separation and exhibited contrasting excess Gibbs energy contributions in the LCST and UCST regimes. Furthermore, analysis of scaled Gibbs energy was carried out to elucidate the energetics of phase separation and differentiate between LCST and UCST thermodynamically. Consequently, we introduce the solvent Reduced Activity Coefficient (RAC) which was used to successfully predict the phase separation behavior without evaluating the Gibbs energy function, thus saving significant computation time.