Non-Equilibrium Phenomena in Liquids and Solutions

NON-EQUILIBRIUM PHENOMENA IN LIQUIDS AND SOLUTIONS On the basis of equation (6.3.8),... 

Free energy calculations for the uptake of HO2 and of its conjugated basis, the superoxide anion O2, made possible an estimation of the pK and redox potentials at the air-water interface [27]. The QM/MM calculations for the interface pK of HO2 yield 6.3 0.5 (experimental value is 4.8 in bulk water), whereas estimation of the redox potential of the O2/O2 couple at the interface yields —0.65 eV (experimental value is -0.33 eV in bulk water). Obviously, the precise definition of these quantities at the interface is not straightforward since it implicates a system characterized by large fluctuations and non-equilibrium phenomena (see below) indeed, some usual chemical concepts in bulk solution may need to be revisited when handling with liquid interfaces. 

In order to develop the liquid membrane techniques, i.e., emulsion Hquid membrane (ELM), supported liquid membrane (SLM), non-dispersive extraction in hollow fiber membrane (HFM), etc., for practical processes, it is necessary to generate data on equilibrium and kinetics of reactive extraction. Furthermore, a prior demonstration of the phenomena of facilitated transport in a simple liquid membrane system, the so-called bulk liquid membrane (BLM), is thought to be effective. Since discovery by Li [28], the liquid membrane technique has been extensively studied for the separation of metal ion, amino acid, and carboxyHc acid, etc., from dilute aqueous solutions [29]. 

Ternary system consists of one volatile and two nonvolatile components, such phenomena as an azeotropy in liquid-gas equilibria and a formation of binary or ternary compounds are absent. Solid phases of volatile and each non-volatile components are completely immiscible and have the eutectic relations in equilibrium with fluid phases, whereas the solid phases of non-volatile components form a continuous solid solution. 

In water solution containing small particles (i.e., suspended solids or turbidity) and non-surface-active solutes, when air is bubbled through it, little or no particles will be removed by any adsorptive bubble separation process. This is because the particles have virtually no natural affinity for air bubbles and hence there is no adhesion when contact is made. This particular phenomena may be explained by the contact angle between a particle and an air bubble. Consider the case of the three-phase fine of contact between a smooth, rigid, solid phase, a liquid phase and a gas phase. The equilibrium contact angle can be expressed in terms of the average surface tensions (i.e., interfacial tensions, dyne/cm) of the liquid-gas solid-liquid (r j ), and solid-gas (r ) interfaces, by the well-known Young s equation ... 

---