Kinetics Characterization of Ion Release under Dynamic and Batch Conditions. I. Weak Acid and Weak Base Ion Exchange Resins |
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Authors: | A Torrado M Valiente |
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Institution: | (1) Departament de Quimica, Química Analítica, Universitat Autònoma de Barcelona, Centre GTS, Edifici CN, Bellaterra, Barcelona, 08193, Spain |
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Abstract: | The aim of the present work is concerned with a study of the kinetics of release of both Ca2+ and F− from the corresponding loaded ion-exchange resins (weak acid and weak base character for Ca2+ for F−, respectively), using both dynamic and batch experimental conditions with an artificial saliva solution as the ion-exchange
media at 293 and 310 K. The influence of resin particle size and the temperature were evaluated by the kinetics parameters
for the effective rate of release (B) and diffusion coefficient (D). The rate of ion release increases with temperature and decreases with particle size. The experimental data were well fitted
by models based on intraparticle diffusion-controlled processes. In dynamic studies, the linear dependence of −log 10(B) with the diameter of the resin particles can be applied for the estimation of B values when resins of low particle size are considered. In batch processes, although resins of low particle size can be studied,
a linear relationship was only attained for the case of slow ion-exchange kinetic systems. |
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Keywords: | Ion exchange Kinetics release Macroporous ion exchanger Intraparticle diffusion |
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