Lado, J.J. and Wouters, J.J. and Tejedor-Tejedor, M.I. and Anderson, M.A. and García-Calvo, E. (2013) Asymmetric Capacitive Deionization Utilizing Low Surface Area Carbon Electrodes Coated with Nanoporous Thin-Films of Al2O3 and SiO2. Journal of The Electrochemical Society, 160 (8). pp. 71-78.
Full text not available from this repository. (Request a copy)Abstract
Capacitive deionization (CDI) has recently gained some degree of popularity as a water treatment technology. This paper demonstrates the benefits of coating low surface area carbon electrodes with a sub-micron nanoporous layer of either γ-Al2O3 or SiO2. As shown by cyclic voltammetry, the oxide layer, having pores sizes ranging from larger micro to meso, substantially increased capacitance for ion removal while still maintaining reasonably high ohmic conductivity. The amount of Ca2+ removed in a CDI cell comprised of a SiO2 coated carbon as the negative and γ-Al2O3 carbon as the positive electrode was nearly five times higher than a cell with uncoated electrodes. Removal of Ca2+ followed pseudo first order kinetics, while Cl- removal was better described by a first order kinetic equation. The highest value for Ca2+ adsorption measured was 0.17 mEq/g of electrode material. This compares favorably with previously reported literature values obtained with high surface area carbons. The removal of Ca2+ and Cl− proved to be asymmetric (mEq Ca2+ > mEq Cl− removed). Consequently, to maintain electroneutrality, pH decreased during the removal process. Furthermore, some of the asymmetry was found to be due to a parasitic reaction, that of Cl− ions being oxidized to ClO3−.
| Item Type: | Article |
|---|---|
| Subjects: | T Technology > TD Environmental technology. Sanitary engineering T Technology > TP Chemical technology |
| Divisions: | Faculty of Engineering, Science and Mathematics > School of Chemistry |
| Depositing User: | Users 11 not found. |
| Date Deposited: | 07 Oct 2013 07:23 |
| Last Modified: | 07 Oct 2013 07:23 |
| URI: | http://eprints.imdea-agua.org:13000/id/eprint/311 |
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