Journal article
Deposition mechanisms of TiO2 nanoparticles in a parallel plate system
Journal of colloid and interface science, Vol.369(1), pp.16-22
03/01/2012
Handle:
https://hdl.handle.net/2376/104259
PMID: 22226475
Abstract
In this study, a microscope-based technique was utilized to understand the fundamental mechanisms involved in deposition of TiO(2) nanoparticles (TNPs). Transport and deposition studies were conducted in a parallel plate (PP) flow chamber with TNP labeled with fluorescein isothiocyanate (FITC) for visualization. Attachment of FITC-labeled TNPs on surfaces is a function of a combination of parameters, including ionic strength (IS), pH and flowrate. Significantly higher deposition rates were observed at pH 5 versus pH 7. This is attributed to the conditions being chemically favorable for deposition at pH 5 as compared to pH 7, as predicted by DLVO theory. Additionally, deposition rates at pH 5 were reduced with IS below 10 mM due to the decrease in range of electrostatic attractive forces. Above 10 mM, aggregate size increased, resulting in higher deposition rates. At pH 7, no deposition was observed below 10 mM and above this concentration, deposition increased with IS. The impact of flowrate was also observed, with decreasing flowrate leading to greater deposition due to the reduction in drag force acting on the aggregate (regardless of pH). Comparisons between experimental and theoretical approximations indicate that non-DLVO type forces also play a significant role. This combination of observations suggest that the deposition of these model nanoparticles on glass surfaces was controlled by a combination of DLVO and non-DLVO-type forces, shear rate, aggregation state, and gravitational force acting on TNPs.
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Details
- Title
- Deposition mechanisms of TiO2 nanoparticles in a parallel plate system
- Creators
- Indranil Chowdhury - Department of Chemical & Environmental Engineering, University of California, Riverside, CA 92521, United StatesSharon L Walker
- Publication Details
- Journal of colloid and interface science, Vol.369(1), pp.16-22
- Academic Unit
- Civil and Environmental Engineering, Department of
- Publisher
- United States
- Identifiers
- 99900546605701842
- Language
- English
- Resource Type
- Journal article