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Principles of Main Experimental Methods
Published in P.J. Gellings, H.J.M. Bouwmeester, Electrochemistry, 2019
Plateaus of the same cell voltage belong to the same three-phase region for all samples with different Cu:Ge ratios. In Figure 9.3, these results are transduced into Gibbs’ phase diagram (“triangle”). By connecting the borders of the three-phase voltage plateau regions, one ternary phase, CuGeO3, is found at the experimental temperature of 900°C. Three-phase regions which have one side in common with one of the binary legs of the electroactive component (Cu-O or Ge-O) show the same emf as the corresponding two-phase regions of the binary system. The third phase has no (or only little) influence, since it does not become involved in the cell reaction (with the exception of some dissolution of the third component in the binary phases). Only the relative ratios of the binary compounds along the binary legs are changed by the coulometric titration.
Solvent Extraction in the Nuclear Fuel Cycle
Published in Reid A. Peterson, Engineering Separations Unit Operations for Nuclear Processing, 2019
Gabriel B. Hall, Susan E. Asmussen, Amanda J. Casella
Ideally, the aqueous and organic phases will separate cleanly and efficiently. Numerous instances from early on in nuclear fuel separations have demonstrated that this is not always the case (HAPO 1955). Common occurrences observed in these operations are buildup of interfacial crud, formation of stable emulsions, foaming, and third phase formation (i.e., phase splitting and inversion). These occurrences can hinder process flow, reduce separation factors, and jeopardize both criticality and fire safety. Figure 4.11 illustrates various examples of separations, including a clean separation, crud formation at an interface, third phase formation, and stable emulsion formation.
Interfacial Catalysis at Oil/Water Interfaces
Published in Alexander G. Vdlkdv, Interfacial Catalysis, 2002
From the point of view of industrial practice, the formation of a third phase provides not only enhancement of the reaction rate, but also easier separation of the PT catalyst from the product stream than that in a two-liquid phase. However, in some particular reaction systems, the catalyst could lose as much as approximately 25% of the initial amount used. Catalysis by TLPTC was briefly reviewed by Naik and Doraiswamy in 1998 [223]. The key results from the previous publications are discussed as follows.
Evidence of Supramolecular Origin of Selectivity in Solvent Extraction of Bifunctional Amidophosphonate Extractants with Different Configurations
Published in Solvent Extraction and Ion Exchange, 2022
Alexandre Artese, Sandrine Dourdain, Nathalie Boubals, Thomas Dumas, Pier Lorenzo Solari, Denis Menut, Laurence Berthon, Philippe Guilbaud, Stéphane Pellet-Rostaing
Solvent extraction is at the heart of various applications related to the production or recycling of precious metals,[1,2] rare earth, electronic wastes,[3,4] or biologic compounds for food and pharmaceutical industries.[5] In the last decades, big efforts of research have been devoted to the understanding of solvent extraction mechanisms to get closer to a predictive approach. Effect of essential parameters on extraction efficiency are nowadays understood and controlled. Third phase formation, which is a major drawback of solvent extraction when the organic phase splits into two phases, can, for example, be avoided by modifying the acidity or the extractant concentration in the extraction phases.[6–8] Extraction efficiency toward one metallic cation can be modified by controlling the chelation site of the extractant molecule, the acid concentration,[9,10] or by employing a synergistic formulation.[11]