Journal article
Proton-promoted dissolution of α-FeOOH nanorods and microrods: Size dependence, anion effects (carbonate and phosphate), aggregation and surface adsorption
Journal of colloid and interface science, Vol.385(1), pp.15-23
11/01/2012
DOI: 10.1016/j.jcis.2012.06.049
PMID: 22867861
Abstract
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► Enhance dissolution from nanorods compared to microrods, in the absence of added oxyanions. ► Oxyanions enhance dissolution from microrods whereas they quench nanorod dissolution. ► These differences between the effect of carbonate and phosphate are due to particle aggregation. ► Surface adsorption behavior of oxyanions on nanorods compared to microrods shows important differences.
Iron-containing oxide nanoparticles are of great interest from a number of technological perspectives and they are also present in the natural environment. Although recent evidence suggests that particle size plays an important role in the dissolution of metal oxides, a detailed fundamental understanding of the influence of particle size is just beginning to emerge. In the current study, we investigate whether nanoscale size-effects are observed for the dissolution of iron oxyhydroxide under different conditions. The dissolution of two particle sizes of goethite, α-FeOOH in the nanoscale and microscale size regimes (herein referred to as nanorods and microrods), in aqueous suspensions at pH 2 is investigated. It is shown here that in the presence of nitrate, nanorods shows greater dissolution on both a per mass and per surface area basis relative to microrods, in agreement with earlier studies. In the presence of carbonate and phosphate, however, dissolution of α-FeOOH nanorods at pH 2 is significantly inhibited, despite the fact that these anions result in a three- to fivefold enhancement of the dissolution of microrods relative to the nitrate anion. Light scattering techniques and electron microscopy show that nanorod suspensions are less stable compared to microrod suspensions resulting in nanorod aggregation under conditions where microrods stay more dispersed. Furthermore, spectroscopic studies using ATR–FTIR spectroscopy show distinct differences in phosphate and carbonate adsorption on nanorods compared to microrods. These results demonstrate that aggregation and the details of surface adsorption are important in the dissolution behavior of nanoscale materials.
Details
- Title: Subtitle
- Proton-promoted dissolution of α-FeOOH nanorods and microrods: Size dependence, anion effects (carbonate and phosphate), aggregation and surface adsorption
- Creators
- Gayan Rubasinghege - Department of Chemistry, University of Iowa, Iowa City, IA 52242, United StatesPatrick K Kyei - Department of Chemistry, University of Iowa, Iowa City, IA 52242, United StatesMichelle M Scherer - Department of Civil and Environmental Engineering, University of Iowa, Iowa City, IA 52242, United StatesVicki H Grassian - Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
- Resource Type
- Journal article
- Publication Details
- Journal of colloid and interface science, Vol.385(1), pp.15-23
- Publisher
- Elsevier Inc
- DOI
- 10.1016/j.jcis.2012.06.049
- PMID
- 22867861
- ISSN
- 0021-9797
- eISSN
- 1095-7103
- Language
- English
- Date published
- 11/01/2012
- Academic Unit
- Civil and Environmental Engineering; Occupational and Environmental Health; Chemistry; Chemical and Biochemical Engineering
- Record Identifier
- 9983992095102771
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