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Composite cryo-beads of chitosan reinforced with natural zeolites with remarkable elasticity and switching on/off selectivity for heavy metal ions.
- Source :
-
International journal of biological macromolecules [Int J Biol Macromol] 2020 Dec 01; Vol. 164, pp. 2432-2449. Date of Electronic Publication: 2020 Aug 05. - Publication Year :
- 2020
-
Abstract
- Combining ion-imprinting technology with pH-dependent adsorptive features of acid- or salt-activated zeolites brings up the opportunity to develop composite polymer materials with 'desired' sorption properties and performances. In this respect, we present here Co <superscript>2+</superscript> -imprinted composite cryo-beads with switching on/off selectivity towards the template ions, engineered by selecting the appropriate zeolite-treatment conditions and/or controlling the initial sorption pH values. Co <superscript>2+</superscript> chelating efficiency of all cryo-beads was investigated either at pH 4 or 6 depending on zeolite conditioning strategy. The maximum sorption capacity values of ion-imprinted cryo-beads were from about 5 up to 7 times higher compared with those of non-imprinted ones. Under competitive conditions (Cu <superscript>2+</superscript> , Ni <superscript>2+</superscript> , Fe <superscript>2+</superscript> and Cd <superscript>2+</superscript> ions), the change of pH value from 4 to 6 resulted in a remarkable quenching of Co <superscript>2+</superscript> selectivity generated by the zeolite shift from the H <superscript>+</superscript> -form to the Na <superscript>+</superscript> -form. The presence of zeolites within cryogel matrix generated composites with outstanding elasticity that allows the instant recovery of gels after full compression. These results indicate that the cryogel-type composites can be successfully re-used in separation processes for several times without losing their features.<br /> (Copyright © 2020 Elsevier B.V. All rights reserved.)
Details
- Language :
- English
- ISSN :
- 1879-0003
- Volume :
- 164
- Database :
- MEDLINE
- Journal :
- International journal of biological macromolecules
- Publication Type :
- Academic Journal
- Accession number :
- 32763407
- Full Text :
- https://doi.org/10.1016/j.ijbiomac.2020.08.009