Modelling ion exchange kinetics in zeolyte-type materials using Maxwell-Stefan approach
authors Lito, PF; Aniceto, JPS; Silva, CM
nationality International
journal DESALINATION AND WATER TREATMENT
author keywords Ion exchange; Kinetics; Modelling; Maxwell-Stefan; Diffusion; Titanosilicate
keywords MICROPOROUS TITANOSILICATE ETS-10; AQUEOUS-SOLUTION; ELECTROLYSIS PROCESS; REMOVAL; DIFFUSION; EQUILIBRIUM; SORPTION; WASTEWATERS; EQUATIONS; WATERS
abstract In this essay, the Maxwell-Stefan (MS) formalism was adopted to model the removal of cadmium(II) and mercury(II) ions from aqueous solutions using microporous titanosilicate ETS-4. The embodied transport mechanism is surface diffusion, since the small pore diameters of such zeolite-type materials imply that counter ions never escape from the force field of the matrix co-ions, mainly owing to the strong and long range electrostatic interactions. The parameters of the global model are the MS diffusivities of ion-ion and ion-solid pairs, and a convective mass transfer coefficient. The average absolute relative deviations (AARD) achieved for Cd2+/Na+/ETS-4 and Hg2+/Na+/ETS-4 systems were only 3.47 and 7.34%, respectively. The model calculates concentration profiles and their evolution along time under transient regime, being able to represent the initial steep branches of removal curves and subsequent transition to equilibrium, where kinetic curves are frequently very difficult to fit. The well-known and frequently used pseudo-first and pseudo-second-order equations were also chosen for comparison, and provided large deviations: AARD(Cd2+) = 48.9% and AARD(Hg2+) = 26.6 % (first order), and AARD(Cd2+) = 29.0% and AARD(Hg2+) = 54.6% (second order).
publisher TAYLOR & FRANCIS INC
issn 1944-3994
year published 2014
volume 52
issue 28-30
beginning page 5333
ending page 5342
digital object identifier (doi) 10.1080/19443994.2013.815682
web of science category Engineering, Chemical; Water Resources
subject category Engineering; Water Resources
unique article identifier WOS:000341653300017
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  impact metrics
times cited (wos core): 3
journal impact factor (jcr 2016): 1.631
5 year journal impact factor (jcr 2016): 1.643
category normalized journal impact factor percentile (jcr 2016): 51.593
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