Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/78845
Type: Artigo de periódico
Title: Coexistence of liquid phases in the sodium polyphosphate-chromium nitrate-water system
Author: de Azevedo, MMM
Bueno, MIMS
Davanzo, CU
Galembeck, F
Abstract: The formation of coexisting liquid phases out of aqueous aluminum polyphosphate solutions was previously suggested as an essential step in aluminum polyphosphate nanoparticle formation. This hypothesis could not be directly verified because the separation of the two phases is very difficult, but a different situation was found in the case of chromium (III) polyphosphate. The phase diagram of the sodium polyphosphate-chromium nitrate-water system at 25 C presents an extensive region with two coexisting liquid phases (L-L), together with a single liquid phase (L) and a solid-liquid (S-L) domain. Within the L-L region, admixture of the reagents produces initially a turbid liquid, out of which two transparent liquid phases separate in a short time, under gravity: one is dense, dark, and viscous while the other has a light color and a lower density. The amounts of the separated phases were determined, as well as their viscosities, densities, pH, UV-vis spectra, and relevant molalities: P (from polyphosphate), Cr(3+), NO(3+)(-), and Na(+). The two liquid phases undergo significant color, pH, and viscosity changes with time. The calculated phase diagrams display the major features of the experimental phase diagram. (C) 2002 Elsevier Science (USA).
Subject: polyphosphate
chromium (III)
liquid-liquid phase
phase separation
aqueous phase equilibria
Country: EUA
Editor: Academic Press Inc Elsevier Science
Rights: fechado
Identifier DOI: 10.1006/jcis.2001.8201
Date Issue: 2002
Appears in Collections:Unicamp - Artigos e Outros Documentos

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