authors |
Cardoso, SP; Azenha, IS; Lin, Z; Portugal, I; Rodrigues, AE; Silva, CM |
nationality |
International |
journal |
CHEMICAL ENGINEERING JOURNAL |
author keywords |
Cadmium; Ion exchange; Mass action law; Maxwell-Stefan; Microporous stannosilicate AV-6; Nernst-Planck |
keywords |
LANTHANIDE SILICATE EU-AV-20; MAXWELL-STEFAN APPROACH; EXCESS GIBBS ENERGY; TITANOSILICATE ETS-4; AQUEOUS-SOLUTION; STRUCTURAL-CHARACTERIZATION; MASS-TRANSFER; METAL-IONS; REMOVAL; SYSTEMS |
abstract |
Microporous stannosilicate AV-6 was investigated for cadmium(II) removal from aqueous solutions in batch experiments. Ion exchange equilibrium of the Cd2+/K+/AV-6 system was modeled using the mass action law combined with activity coefficient models for the solution (ideal, Debye-Htickel and Pitzer equations) and for the solid (Wilson equation) with absolute average relative deviations (AARDs) between 6.56% and 6.75%. It was concluded that the system embodies strong intraparticle non-idealities, namely solid activity coefficients between 0.2602 and 0.7180 for Cd2+. The kinetics of cadmium(II) sorption was analyzed measuring removal curves and modeling the data with pseudo-first and pseudo-second order expressions, commonly adopted in the literature, and with Maxwell-Stefan (MS) and Nernst-Plank (NP) based models. The best results were achieved by MS and NP approaches, for which AARD was 3.74% and 3.71%, respectively. The kinetic performance of the ion exchange was also discussed taking into account structural aspects of the AV-6 material. (C) 2016 Elsevier B.V. All rights reserved. |
publisher |
ELSEVIER SCIENCE SA |
issn |
1385-8947 |
year published |
2016 |
volume |
295 |
beginning page |
139 |
ending page |
151 |
digital object identifier (doi) |
10.1016/j.cej.2016.03.007 |
web of science category |
Engineering, Environmental; Engineering, Chemical |
subject category |
Engineering |
unique article identifier |
WOS:000375507300016
|