Behaviour of Fe-oxides relevant to contaminant uptake in the environment

Stipp, S. L. S.; Hansen, Mikkel Fougt; Kristensen, R.; Hochella, Michael F.; Bennedsen, Lars Rønn; Dideriksen, Knud; Balić-Žunić, Tonči; Leonard, Donovan N.; Mathieu, H. J.

doi:10.1016/s0009-2541(02)00123-7

Cited by 115 publications

(71 citation statements)

References 22 publications

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“…The force curves record tip-sample separation, so each curve is corrected for cantilever bending. A force map is constructed from data from 10,000 curves, each representing 1 pixel in a 50-ϫ 50-nm 2 area that is a little larger than typical AFM imaging (17). However, many chalk particles are Ͼ50 nm in diameter, so this pixel size is small enough to reveal coccolith elements or single, euhedral crystals.…”

Section: Afm Force Mappingmentioning

confidence: 99%

Probing the intrinsically oil-wet surfaces of pores in North Sea chalk at subpore resolution

Hassenkam

Skovbjerg

Stipp

2009

Proc. Natl. Acad. Sci. U.S.A.

134

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Pore surface properties control oil recovery. This is especially true for chalk reservoirs, where pores are particularly small. Wettability, the tendency for a surface to cover itself with fluid, is traditionally defined by the angle a droplet makes with a surface, but this macroscopic definition is meaningless when the particles are smaller than even the smallest droplet. Understanding surface wetting, at the pore scale, will provide clues for more effective oil recovery. We used a special mode of atomic force microscopy and a hydrophobic tip to collect matrices of 10,000 force curves over 5-؋ 5-m 2 areas on internal pore surfaces and constructed maps of topography, adhesion, and elasticity. We investigated chalk samples from a water-bearing formation in the Danish North Sea oil fields that had never seen oil. Wettability and elasticity were inhomogeneous over scales of 10s of nanometers, smaller than individual chalk particles. Some areas were soft and hydrophobic, whereas others showed no correlation between hardness and adhesion. We conclude that the macroscopic parameter, ''wetting,'' averages the nanoscopic behavior along fluid pathways, and ''mixed-wet'' samples have patches with vastly different properties. Development of reservoir hydrophobicity has been attributed to infiltrating oil, but these new results prove that wettability and elasticity are inherent properties of chalk. Their variability, even on single particles, must result from material originally present during sedimentation or material sorbed from the pore fluid some time later.AFM ͉ force maps ͉ wettability ͉ oil recovery ͉ adhesion

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Section: Afm Force Mappingmentioning

confidence: 99%

Probing the intrinsically oil-wet surfaces of pores in North Sea chalk at subpore resolution

Hassenkam

Skovbjerg

Stipp

2009

Proc. Natl. Acad. Sci. U.S.A.

134

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“…Iron (oxyhydr)oxides which can be formed through the weathering of many kinds of rocks and iron based clays, are ubiquitous in the environment and play significant roles in geochemical process (Stipp et al, 2002;Pedersen et al, 2006). In the family of iron (oxyhydr)oxides, ferrihydrite (Fh) is considered as one of the most distinct minerals, as it is a precursor to other iron minerals such as goethite and hematite (Jambor and Dutrizac, 1998;Meng et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Co-adsorption of phosphate and zinc(II) on the surface of ferrihydrite

et al. 2016

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h i g h l i g h t s• Phosphate and Zn(II) exhibited a synergistic adsorption on Ferrihydrite.• The effects of pH on the adsorption of the two contaminants were investigated.• XPS and ATR-FTIR demonstrated ternary complexes were formed on Ferrihydrite.• A phosphate-bridged ternary complexes model was proposed. a r t i c l e i n f o b s t r a c tFerrihydrite (Fh) is of great importance in affecting the migration and transformation of heavy-metal cations and oxyanions. To advance the understanding of co-adsorption reactions on Fh surface, the coadsorption of phosphate and Zn(II) from aqueous solution to a synthesized Fh was determined. The batch experiments demonstrated a synergistic adsorption of phosphate and Zn(II) on Fh. In the pH range of 3.5-6, the adsorption of the two contaminants showed strong pH dependence in the single solute adsorption systems, but the dependence alleviated in the simultaneous adsorption system. X-ray photoelectron spectroscopy (XPS) revealed that the chemical shifts of Zn 2p 1/2 and Zn 2p 3/2 binding energies were more significant than that of P 2p in the single and simultaneous adsorption systems. On the other side, in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) observed increased formation of outer-and inner-sphere complexes of phosphate in the simultaneous system. Thus, the synergistic adsorption of the two contaminants could be attributed to the formation of ternary complexes as well as electrostatic interactions, while surface precipitation could not be completely ruled out. On the basis of the results from both the batch adsorption experiments and structural characterization, these two contaminants were likely to form phosphate-bridged ternary complexes (≡Fe-P-Zn) in the simultaneous adsorption system.

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“…While some of the property changes are directly related to the increase of specific surface area, some are emerging from changes in the surface properties and chemistry of these surfaces at or below certain particle sizes. [16][17][18][19][20][21] In other words, surface and particle properties, even when normalised for surface area, often show changes in the nanoscale size range. Characteristics like these are key in understanding metal behaviour in the environment as they alter characteristics of the metal, such as bioavailability and toxicity.…”

Section: Introductionmentioning

confidence: 99%

Using FlFFF and aTEM to determine trace metal–nanoparticle associations in riverbed sediment

et al. 2010

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Environmental context. Determining associations between trace metals and nanoparticles in contaminated systems is important in order to make decisions regarding remediation. This study analysed contaminated sediment from the Clark Fork River Superfund Site and discovered that in the <1-µm fraction the trace metals were almost exclusively associated with nanoparticulate Fe and Ti oxides. This information is relevant because nanoparticles are often more reactive and show altered properties compared with their bulk equivalents, therefore affecting metal toxicity and bioavailability.Abstract. Analytical transmission electron microscopy (aTEM) and flow field flow fractionation (FlFFF) coupled to multi-angle laser light scattering (MALLS) and high-resolution inductively coupled plasma mass spectroscopy (HR-ICPMS) were utilised to elucidate relationships between trace metals and nanoparticles in contaminated sediment. Samples were obtained from the Clark Fork River (Montana, USA), where a large-scale dam removal project has released reservoir sediment contaminated with toxic trace metals (namely Pb, Zn, Cu and As) which had accumulated from a century of mining activities upstream. An aqueous extraction method was used to recover nanoparticles from the sediment for examination; FlFFF results indicate that the toxic metals are held in the nano-size fraction of the sediment and their peak shapes and size distributions correlate best with those for Fe and Ti. TEM data confirms this on a single nanoparticle scale; the toxic metals were found almost exclusively associated with nano-size oxide minerals, most commonly brookite, goethite and lepidocrocite.

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Behaviour of Fe-oxides relevant to contaminant uptake in the environment

Cited by 115 publications

References 22 publications

Probing the intrinsically oil-wet surfaces of pores in North Sea chalk at subpore resolution

Probing the intrinsically oil-wet surfaces of pores in North Sea chalk at subpore resolution

Co-adsorption of phosphate and zinc(II) on the surface of ferrihydrite

Using FlFFF and aTEM to determine trace metal–nanoparticle associations in riverbed sediment

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