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http://hdl.handle.net/10773/19969
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DC Field | Value | Language |
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dc.contributor.author | Figueiredo, Bruno R. | pt |
dc.contributor.author | Ananias, Duarte | pt |
dc.contributor.author | Rocha, Joao | pt |
dc.contributor.author | Silva, Carlos Manuel | pt |
dc.date.accessioned | 2017-12-07T19:31:04Z | - |
dc.date.issued | 2015 | pt |
dc.identifier.issn | 1385-8947 | pt |
dc.identifier.uri | http://hdl.handle.net/10773/19969 | - |
dc.description.abstract | The ion exchange of Cs+ from aqueous solutions was studied using for the first time a microporous lanthanide silicate with photoluminescence properties, Eu-AV-20. It was prepared by hydrothermal synthesis, characterized by SEM, PLS, PXRD and ICP-MS, and several batch ion exchange experiments were performed to measure isotherm and removal curves. Additional curves were measured to evaluate the competition with Na+. The results evidenced the great selectivity of Eu-AV-20 towards Cs+ since cesium removal was slightly modified even for Na+/Cs+ concentrations ratio of 190. The emission photoluminescent spectra of native and Cs+-exchanged Eu-AV-20 were also determined for the first time, and significant modifications were detected, which discloses the potential of Eu-AV-20 for Cs+ sensing purposes. The Langmuir equation provided a good fit to the equilibrium data, with average error of 5.3%, and the Maxwell-Stefan based model adopted to represent the kinetic curves (i.e., concentration versus time) achieved a deviation of 19.0%. An analysis of variance confirmed that the model was statistically significant to represent the uptake curves. The Maxwell-Stefan based model comprises three parameters, namely, the diffusion coefficients associated to the interactions of Cs+ and Eu-AV-20, Na+/K+ and Eu-AV-20, and Cs+ and Na+/K+, whose fitted values were 2.706 x 10(-15), 5.713 x 10(-15) and 9.446 x 10(-12) m(2) s(-1). Such low values evidenced that the intraparticle mass transport mechanism is surface diffusion. This fact is ascribed to the small pores of the Eu-AV-20 crystal, 5.8 x 6.8 angstrom, because the counter ions never escape from the force field of the framework co-ions, mainly due to the strong and long range nature of the electrostatic interactions. (C) 2015 Elsevier B.V.,All rights reserved. | pt |
dc.language.iso | eng | pt |
dc.publisher | ELSEVIER SCIENCE SA | pt |
dc.relation | info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBD%2F75457%2F2010/PT | pt |
dc.relation | info:eu-repo/grantAgreement/FCT/COMPETE/132936/PT | pt |
dc.relation | info:eu-repo/grantAgreement/FCT/5876/147332/PT | pt |
dc.rights | restrictedAccess | por |
dc.subject | MICROPOROUS TITANOSILICATE ETS-4 | pt |
dc.subject | MAXWELL-STEFAN APPROACH | pt |
dc.subject | ZIRCONIUM PHOSPHATE | pt |
dc.subject | TITANIUM SILICATES | pt |
dc.subject | CRYSTAL-STRUCTURES | pt |
dc.subject | RADIOACTIVE-WASTE | pt |
dc.subject | AQUEOUS-SOLUTION | pt |
dc.subject | ACIDIC-SOLUTIONS | pt |
dc.subject | ENERGY-TRANSFER | pt |
dc.subject | WATER SOLUTIONS | pt |
dc.title | Cs+ ion exchange over lanthanide silicate Eu-AV-20: Experimental measurement and modelling | pt |
dc.type | article | pt |
dc.peerreviewed | yes | pt |
ua.distribution | international | pt |
degois.publication.firstPage | 208 | pt |
degois.publication.lastPage | 218 | pt |
degois.publication.title | CHEMICAL ENGINEERING JOURNAL | pt |
degois.publication.volume | 268 | pt |
dc.date.embargo | 10000-01-01 | - |
dc.relation.publisherversion | 10.1016/j.cej.2015.01.048 | pt |
dc.identifier.doi | 10.1016/j.cej.2015.01.048 | pt |
Appears in Collections: | CICECO - Artigos |
Files in This Item:
File | Description | Size | Format | |
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Cs+ ion exchange over lanthanide silicate Eu-AV-20 Experimental measurement and modelling_10.1016j.cej.2015.01.048.pdf | 1.96 MB | Adobe PDF |
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