Abstract
In this study, we have investigated the role of the Ce oxidation state (Ce 3+ /Ce 4+ ) on the CeO 2 surfaces for silicate adsorption. In aqueous medium, the Ce 3+ sites lead to the formation of −OH groups at the CeO 2 surface through H 2 O dissociation. Silicate ions can adsorb onto the CeO 2 surface through interaction with the −OH groups (−Ce−OH− + −Si−O − ↔ −Ce−O−Si− + OH − ). As the Ce 3+ concentration increased from 19.3 to 27.6%, the surface density of −OH group increased from 0.34 to 0.72 OH/nm 2 . To evaluate the adsorption behaviors of silicate ions onto CeO 2 NPs, we carried out an adsorption isothermal analysis, and the adsorption isotherm data followed the Freundlich model. The Freundlich constant for the relative adsorption capacity (K F ) and adsorption intensity (1/n) indicated that CeO 2 NPs with high Ce 3+ concentration show higher adsorption affinity with silicate ions. As a result, we have demonstrated that the Ce oxidation state (Ce 3+ /Ce 4+ ) on the CeO 2 surface can have a significant influence on the silicate adsorption.
| Original language | English |
|---|---|
| Pages (from-to) | 311-315 |
| Number of pages | 5 |
| Journal | Applied Surface Science |
| Volume | 389 |
| DOIs | |
| State | Published - 15 Dec 2016 |
Keywords
- Adsorption isotherm
- Ceria
- Oxidation state
- Particle size
- Silicate ions