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  • 201.
    Gustafsson, Emil
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Hedberg, Jonas
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Larsson, Per A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Johnson, C. Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Vibrational sum frequency spectroscopy on polyelectrolyte multilayers: Effect of molecular surface structure on macroscopic wetting properties2015Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, nr 15, s. 4435-4442Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Adsorption of a single layer of molecules on a surface, or even a reorientation of already present molecules, can significantly affect the surface properties of a material. In this study, vibrational sum frequency spectroscopy (VSFS) has been used to study the change in molecular structure at the solid-air interface following thermal curing of polyelectrolyte multilayers of poly(allylamine hydrochloride) and poly(acrylic acid). Significant changes in the VSF spectra were observed after curing. These changes were accompanied by a distinct increase in the static water contact angle, showing how the properties of the layer-by-layer molecular structure are controlled not just by the polyelectrolyte in the outermost layer but ultimately by the orientation of the chemical constituents in the outermost layers.

  • 202.
    Gustavsson, John
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Hummelgård, Christine
    Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, SE 851 70 Sundsvall, Sweden.
    Bäckström, Joakim
    Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, SE 851 70 Sundsvall, Sweden.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Rahman, Seikh Mohammed Habibur
    Department of Chemical and Biological Engineering, Chalmers University of Technology, SE 412 96 Gothenburg, Sweden.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Eriksson, Sten
    Department of Chemical and Biological Engineering, Chalmers University of Technology, SE 412 96 Gothenburg, Sweden.
    Cornell, Ann
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    In-situ Activated Hydrogen Evolution by Molybdate Addition to Neutral and Alkaline ElectrolytesManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Activation of the hydrogen evolution reaction (HER) by in-situ addition of Mo(VI) to the electrolyte has been studied in alkaline and pH neutral electrolytes, the latter with the chlorate process in focus. Catalytic molybdenum containing films formed on the cathodes during polarization were investigated using scanning electron microscopy (SEM), energy-dispersive X‑ray analysis (EDS), X-ray photoelectron spectroscopy (XPS), and X‑ray fluorescence (XRF). In-situ addition of Mo(VI) activates the HER on titanium in both alkaline and neutral electrolytes and makes the reaction kinetics independent of the substrate material. Films formed in neutral electrolyte consisted of molybdenum oxides and contained more molybdenum than those formed in alkaline solution. Films formed in neutral electrolyte in the presence of phosphate buffer activated the HER, but were too thin to be detected by EDS. Since molybdenum oxides are generally not stable in strongly alkaline electrolyte, films formed in alkaline electrolyte were thinner and probably co-deposited with iron. A cast iron‑molybdenum alloy was also investigated with respect to activity for HER. When polished in the same way as iron, the alloy displayed a similar activity for HER as pure iron.

  • 203.
    Göthelid, Mats
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Materialfysik, MF.
    Hosseinpour, S.
    Ahmadi, S.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Johnson, C. Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Hexane selenol dissociation on Cu: The protective role of oxide and water2017Ingår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 423, s. 716-720Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hexane selenol (CH3(CH2)5SeH) was adsorbed from gas phase in ultra-high vacuum on polycrystalline Cu and studied with synchrotron radiation based photoelectron spectroscopy (PES) and Near edge X-ray absorption fine structure spectroscopy (NEXAFS). Adsorption was done on a bare copper surface at room temperature (RT), on a thin oxide on Cu at room temperature, and on a thin layer of water on Cu at 140 K.

  • 204.
    Halldin Stenlid, Joakim
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Johansson, Adam Johannes
    Leygraf, Christopher
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Brinck, Tore
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Computational Analysis of the Early Stage of Cuprous Oxide Sulphidation: A Top-Down Process2017Ingår i: Corrosion Engineering, Science and Technology, ISSN 1478-422X, E-ISSN 1743-2782, Vol. 52, nr S1, s. 50-53Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The initial steps of Cu2O sulphidation to Cu2S have been studied using plane-wave density functional theory at the PBE-D3+U level of sophistication. Surface adsorption and dissociation of H2S and H2O, as well as the replacement reaction of lattice oxygen with sulphur, have been investigated for the most stable (111) and (100) surface facets under oxygen-lean conditions. We find that the (100) surface is more susceptible to sulphidation than the (111) surface, promoting both H2S adsorption, dissociation and the continued oxygen–sulphur replacement. The results presented in this proceeding bridge previous results from high-vacuum experiments on ideal surface to more realistic corrosion conditions and set the grounds for future mechanistic studies. Potential implications on the long-term final disposal of spent nuclear fuel are discussed.

  • 205.
    Halldin Stenlid, Joakim
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Soldemo, Markus
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Johansson, A. J.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Götelid, Mats
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Weissenrieder, Jonas
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Brinck, Tore
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Reactivity at the Cu2O(100):Cu-H2O interface: a combined DFT and PES study2016Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 18, nr 44, s. 30570-30584Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The water-cuprite interface plays an important role in dictating surface related properties. This not only applies to the oxide, but also to metallic copper, which is covered by an oxide film under typical operational conditions. In order to extend the currently scarce knowledge of the details of the water-oxide interplay, water interactions and reactions on a common Cu2O(100):Cu surface have been studied using high-resolution photoelectron spectroscopy (PES) as well as Hubbard U and dispersion corrected density functional theory (PBE-D3+U) calculations up to a bilayer water coverage. The PBE-D3+U results are compared with PBE, PBE-D3 and hybrid HSE06-D3 calculation results. Both computational and experimental results support a thermodynamically favored, and H2O coverage independent, surface OH coverage of 0.25-0.5 ML, which is larger than the previously reported value. The computations indicate that the results are consistent also for ambient temperatures under wet/humid and oxygen lean conditions. In addition, both DFT and PES results indicate that the initial (3,0; 1,1) surface reconstruction is lifted upon water adsorption to form an unreconstructed (1 x 1) Cu2O(100) structure.

  • 206. Hansson, P. M.
    et al.
    Swerin, A.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. YKI, Institute for Surface Chemistry, Stockholm, Sweden .
    Schoelkopf, J.
    Gane, P. A. C.
    Effect of local curvature on the interaction between hydrophobic surfaces2010Ingår i: Nanotechnology 2010: Advanced Materials, CNTs, Particles, Films and Composites - Technical Proceedings of the 2010 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2010: Volume 1, 2010, s. 61-64Konferensbidrag (Refereegranskat)
    Abstract [en]

    Surface structure, including roughness and chemical heterogeneities, is known to be of importance for the surface interaction forces observed between hydrophobic and superhydrophobic surfaces. In this study, silica particles have been used to prepare structured particulated surfaces with a controlled roughness using Langmuir-Blodgett deposition or a drop coating technique. The surfaces were characterized by SEM and AFM. The AFM colloidal probe technique was employed for probing the interaction between a micro-size hydrophobic particle and hydrophobic surfaces with a sintered and silanized nano-sized silica particle monolayer. These measurements indicate that the adhesion force is increased by a decrease in particle size. Larger roughness gives larger crevices on the surface and more air/vapor accumulation but the capillary growth is impaired since the three-phase line (solid-liquid-air) has to move over a longer distance with an increase in the size of the surface features.

  • 207.
    Hansson, Petra M
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Hydrophobic surfaces: Effect of surface structure on wetting and interaction forces2012Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The use of hydrophobic surfaces is important for many processes both in nature and industry. Interactions between hydrophobic species play a key role in industrial applications such as water-cleaning procedures and pitch control during papermaking but they also give information on how to design surfaces like hydrophobic mineral pigments.

    In this thesis, the influence of surface properties on wetting and interaction forces has been studied. Surfaces with close-packed particles, pore arrays, randomly deposited nanoparticles as well as reference surfaces were prepared. The atomic force microscope (AFM) was utilized for force and friction measurements while contact angles and confocal Raman microscopy experiments were mainly used for wetting studies.

    The deposition of silica particles in the size range of nano- to micrometers using the Langmuir-Blodgett (LB) technique resulted in particle coated surfaces exhibiting hexagonal close-packing and close to Wenzel state wetting after hydrophobization. Force measurements displayed long-range interaction forces assigned to be a consequence of air cavitation. Smaller roughness features provided larger forces and interaction distances interpreted as being due to fewer restrictions of capillary growth. Friction measurements proved both the surface structure and chemistry to be important for the observed forces.

    On hydrophobic pore array surfaces, the three-phase contact line of water droplets avoided the pores which created a jagged interface. The influence of the pores was evident in the force curves, both in terms of the shape, in which the three-phase contact line movements around the pores could be detected, as well as the depth of the pores providing different access and amount of air. When water/ethanol mixtures were used, the interactions were concluded to be due to ethanol condensation.

    Confocal Raman microscopy experiments with water and water/ethanol mixtures on superhydrophobic surfaces gave evidence for water depletion and ethanol/air accumulation close to the surface. Force measurements using superhydrophobic surfaces showed extremely long-range interaction distances.

    This work has provided evidence for air cavitation between hydrophobic surfaces in aqueous solution. It was also shown that the range and magnitude of interaction forces could, to some extent, be predicted by looking at certain surface features like structure,roughness and the overall length scales.

  • 208. Hansson, Petra M.
    et al.
    Claesson, Per M.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Swerin, Agne
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Briscoe, Wuge H.
    Schoelkopf, Joachim
    Gane, Patrick A. C.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Frictional forces between hydrophilic and hydrophobic particle coated nanostructured surfaces2013Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, nr 41, s. 17893-17902Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Friction forces have long been associated with the famous Amontons' rule that states that the friction force is linearly dependent on the applied normal load, with the proportionality constant being known as the friction coefficient. Amontons' rule is however purely phenomenological and does not in itself provide any information on why the friction coefficient is different for different material combinations. In this study, friction forces between a colloidal probe and nanostructured particle coated surfaces in an aqueous environment exhibiting different roughness length scales were measured by utilizing the atomic force microscope (AFM). The chemistry of the surfaces and the probe was varied between hydrophilic silica and hydrophobized silica. For hydrophilic silica surfaces, the friction coefficient was significantly higher for the particle coated surfaces than on the flat reference surface. All the particle coated surfaces exhibited similar friction coefficients, from which it may be concluded that the surface geometry, and not the roughness amplitude per se, influenced the measured friction. During measurements with hydrophobic surfaces, strong adhesive forces related to the formation of a bridging air cavity were evident from both normal force and friction force measurements. In contrast to the frictional forces between the hydrophilic surfaces, the friction coefficient for hydrophobic surfaces was found to depend on the surface structure and we believe that this dependence is related to the restricted movement of the three-phase line of the bridging air cavity. For measurements using a hydrophobic surface and a hydrophilic probe, the friction coefficient was significantly smaller compared to the two homogeneous systems. A layer of air or air bubbles on the hydrophobic surface working as a lubricating layer is a possible mechanism behind this observation.

  • 209.
    Hansson, Petra M
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Swerin, Agne
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Schoelkopf, Joachim
    Gane, Patrick A. C.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Frictional forces between hydrophilic and hydrophobic particle coated nanostructured surfacesManuskript (preprint) (Övrigt vetenskapligt)
  • 210.
    Hansson, Petra M.
    et al.
    YKI, Ytkemiska Institutet AB.
    Hormozan, Yashar
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik.
    Brandner, B. D.
    Linnros, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Swerin, Agne
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Schoelkopf, J.
    Gane, P. A. C.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Effect of surface depressions on wetting and interactions between hydrophobic pore array surfaces2012Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 28, nr 30, s. 11121-11130Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The surface structure is known to significantly affect the long-range capillary forces between hydrophobic surfaces in aqueous solutions. It is, however, not clear how small depressions in the surface will affect the interaction. To clarify this, we have used the AFM colloidal probe technique to measure interactions between hydrophobic microstructured pore array surfaces and a hydrophobic colloidal probe. The pore array surfaces were designed to display two different pore spacings, 1.4 and 4.0 ÎŒm, each with four different pore depths ranging from 0.2 to 12.0 ÎŒm. Water contact angles measured on the pore array surfaces are lower than expected from the Cassie-Baxter and Wenzel models and not affected by the pore depth. This suggests that the position of the three-phase contact line, and not the interactions underneath the droplet, determines the contact angle. Confocal Raman microscopy was used to investigate whether water penetrates into the pores. This is of importance for capillary forces where both the movement of the three-phase contact line and the situation at the solid/liquid interface influence the stability of bridging cavities. By analyzing the shape of the force curves, we distinguish whether the cavity between the probe and the surfaces was formed on a flat part of the surface or in close proximity to a pore. The pore depth and pore spacing were both found to statistically influence the distance at which cavities form as surfaces approach each other and the distance at which cavities rupture during retraction.

  • 211.
    Hansson, Petra M.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Hormozan, Yashar
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik.
    Brandner, Birgit D.
    Linnros, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Swerin, Agne
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Schoelkopf, Joachim
    Gane, Patrick A. C.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Hydrophobic pore array surfaces: Wetting and interaction forces in water/ethanol mixtures2013Ingår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 396, s. 278-286Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Interactions between and wetting behavior of structured hydrophobic surfaces using different concentrations of water/ethanol mixtures have been investigated. Silica surfaces consisting of pore arrays with different pore spacings and pore depths were made hydrophobic by silanization. Their static and dynamic contact angles were found to be independent of the pore depth while fewer pores on the surface, i.e. a closer resemblance to a flat surface, gave a lower contact angle. As expected, a higher amount of ethanol facilitated wetting on all the surfaces tested. Confocal Raman microscopy measurements proved both water and ethanol to penetrate into the pores. AFM colloidal probe force measurements clearly showed that formation of air cavitation was hindered between the hydrophobic surfaces in presence of ethanol, and an increase in ethanol concentration was followed by a smaller jump-in distance and a weaker adhesion force. On separation, an immediate jump-out of contact occurred. The measured forces were interpreted as being due to capillary condensation of ethanol between the surfaces giving rise to very unstable cavities immediately rupturing on surface separation.

  • 212. Hansson, Petra M.
    et al.
    Skedung, Lisa
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Swerin, Agne
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Schoelkopf, Joachim
    Gane, Patrick A. C.
    Rutland, Mark W.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Robust Hydrophobic Surfaces Displaying Different Surface Roughness Scales While Maintaining the Same Wettability2011Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 27, nr 13, s. 8153-8159Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A range of surfaces coated with spherical silica particles, covering the size range from nanometer to micrometer, have been produced using Langmuir-Blodgett (LB) deposition. The particles were characterized both in suspension and in the Langmuir trough to optimize the surface preparation procedure. By limiting the particle aggregation and surface layer failures during the preparation steps, well-defined monolayers with a close-packed structure have been obtained for all particle sizes. Thus, this procedure led to structured surfaces with a characteristic variation in the amplitude and spatial roughness parameters. In order to obtain robust surfaces, a sintering protocol and an AFM-based wear test to determine the stability of the deposited surface layer were employed. Hydrophobization of the LB films followed by water contact angle measurements showed, for all tested particle sizes, the same increase in contact angle compared to the contact angle of a flat hydrophobic surface. This indicates nearly hexagonal packing and gives evidence for nearly, complete surface wetting of the surface features.

  • 213. Hansson, Petra M.
    et al.
    Swerin, Agne
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Schoelkopf, Joachim
    Gane, Patrick A. C.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Influence of Surface Topography on the Interactions between Nanostructured Hydrophobic Surfaces2012Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 28, nr 21, s. 8026-8034Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nanostructured particle coated surfaces, with hydrophobized particles arranged in close to hexagonal order and of specific diameters ranging from 30 nm up to 800 nm, were prepared by Langmuir-Blodgett deposition followed by silanization. These surfaces have been used to study interactions between hydrophobic surfaces and a hydrophobic probe using the AFM colloidal probe technique. The different particle coated surfaces exhibit similar water contact angles, independent of particle size, which facilitates studies of how the roughness length scale affects capillary forces (previously often referred to as "hydrophobic interactions") in aqueous solutions. For surfaces with smaller particles (diameter < 200 nm), an increase in roughness length scale is accompanied by a decrease in adhesion force and bubble rupture distance. It is suggested that this is caused by energy barriers that prevent the motion of the three-phase (vapor/liquid/solid) line over the surface features, which counteracts capillary growth. Some of the measured force curves display extremely long-range interaction behavior with rupture distances of several micrometers and capillary growth with an increase in volume during retraction. This is thought to be a consequence of nanobubbles resting on top of the surface features and an influx of air from the crevices between the particles on the surface.

  • 214.
    Hedberg, Jonas
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    A Molecular view of inital Atmospheric Corrosion: In situ surface studies of zinc based on vibrational spectroscopy2009Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Atmospheric corrosion takes place on most metals as they interact with thesurrounding environment. A degradation of the metal is the common result,which often leads to a shortened lifespan of the material. Hence, knowledge onthe fundamental interaction between a gas containing corrosive constituentsand a metal surface, which is the starting point of atmospheric corrosion, isimportant in many contexts. As the nature of atmospheric corrosion is inherentlycomplex, it imposes demands on the analytical studies that are neededin order to understand the fundamentals on a molecular level. Consequently,in-situ vibrational techniques, providing molecular information, have beenutilized in this work to study atmospheric corrosion by targeting the initialstages of the interaction between corrosive air and a metal surface. The initialstages (from minutes until days of exposure) were studied as these havea large influence on the atmospheric corrosion for prolonged exposure times.

    More specifically, the interaction between humidified air to which organicacids were added, and zinc was targeted in order to address a situation inindoor atmospheric corrosion, where organic acids are of importance. Zinc isa constituent in e.g. brass, which is an alloy used in many indoor applications.

    A systematic investigation utilizing complementary acting vibrational techniquesthus enabled detailed information on the mechanisms of the onsetof atmospheric corrosion of zinc induced by acetic and formic acid. Corrosionproducts of both two dimensional and three dimensional character couldbe separately studied by combining VSFS (interface sensitive), IRAS (nearsurfacesensitive), and CRM (bulk sensitive).

    The Zn surface was found to be heterogeneous with different hydroxylgroups present on the surface. As this surface was exposed to formic or aceticacid, the OH groups on the surface were rapidly displaced in a ligand exchangewith formate or acetate. These ligands, organised in two dimensionalstructures, promoted corrosion by weakening the bonds of the Zn atoms totheir surrounding matrix.

    The subsequent growth of three dimensional corrosion products, Zn hydroxyacetate and formate, observed within short exposure times of Zn exposedto acetic and formic acid, was found to be electrochemical in nature.Cathodic areas consisting of more crystalline ZnO were observed. The potentialdifference between these more noble areas on the surface and those of lessnoble character created an electrochemical cell, initiating release of Zn ionsinto the aqueous adlayer in the anodic reactions. These Zn ions precipitatedas localised corrosion products. The cathodic areas increased the local pHon the surface, thereby promoting precipitation in their vicinity. The resultson initial stages of this type of corrosion were found to have similarities withprevious field studies of Zn exposed to real indoor environments.

    One way to decrease the corrosion rate of zinc is by adsorbing a corrosioninhibitor to the metal surface in order to protect it. As a model for sucha corrosion inhibitor, octadecanethiol (CH3(CH2)17SH) was seen to provideincreased corrosion protection of both reduced and oxidised Zn substrates byforming an adsorbed surface layer with an ordered structure.

  • 215.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Baldelli, Steven
    Univ Houston, Dept Chem, Houston, TX 77204 USA.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära (stängd 20081231).
    Initial Atmospheric Corrosion of Zn: Influence of Humidity on the Adsorption of Formic Acid Studied by Vibrational Sum Frequency Spectroscopy2009Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, s. 6169-6173Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The ZnO/Zn surface exposed to formic acid undergoes a partial, reversible dissociation to formate ion, and a protonated surface oxide and is seen to have different hydration states depending on the relative humidity. Under high relative humidity conditions it exists as a formate coordinated to the surface with the oxygen atoms toward the surface and the C-H directed away into the vapor. In a dry environment a formic acid/formate intermediate is formed, although a substantial amount of dissociated species still are present, in both hydrated and nonhydrated form. The results may have implications on the initial atmospheric corrosion of Zn and emphasize that the ZnO/Zn surface is heterogeneous with a range of acid and basic sites for the adsorption of formate and the proton.

  • 216.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Baldelli, Steven
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Molecular Structural Information of the Atmospheric Corrosion of Zinc Studied by Vibrational Spectroscopy Techniques II. Two and Three-Dimensional Growth of Reaction Products Induced by Formic and Acetic Acid2010Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 157, nr 10, s. C363-C373Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In an effort to obtain a more molecular view of atmospheric corrosion, we present experimental data from three complementary acting vibrational spectroscopy techniques that have been used in parallel exposures to follow the initial atmospheric corrosion of zinc during exposure in dry or humid air to which formic acid or acetic acid was added, with the primary aim to simulate indoor exposure conditions. The techniques used were vibrational sum frequency spectroscopy (interface sensitive), IR reflection absorption spectroscopy (near-surface sensitive), and confocal Raman microspectroscopy (bulk sensitive with submicrometer surface lateral resolution). The growth of two-dimensional interface species of zinc formate or zinc acetate could be monitored in situ and distinguished from three-dimensional growth of ZnO and zinc hydroxy formate or acetate. These interface species are believed to act as precursors of the dissolution of aqueous zinc carboxylate species that subsequently deposit at the surface and result in local growth of crystalline or amorphous ZnO and local zinc hydroxy carboxylate. Differences in the growth of corrosion products induced by acetic or formic acid were mainly attributed to differences in pH of the aqueous adlayer and in different deposition velocities of the acids into the aqueous adlayer. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3479255] All rights reserved.

  • 217.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Baldelli, Steven
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Molecular Structural Information of the Atmospheric Corrosion of Zinc Studied by Vibrational Spectroscopy Techniques I. Experimental Approach2010Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 157, nr 10, s. C357-C362Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As the nature of the interactions taking place on a metal surface during atmospheric corrosion is inherently complex, it imposes demands on the analytical studies that are needed to understand the fundamentals on a molecular level. Corrosion products may spread on the metal surface forming two-and three-dimensional structures. Thus, it is imperative to use different techniques to resolve the different types of growth. In this first part of a series of two papers, a systematic investigation is made to obtain detailed information on the mechanisms of the onset of atmospheric corrosion of zinc exposed to 115 ppb acetic acid in either dry or humidified air. The vibrational spectroscopy techniques used were vibrational sum frequency spectroscopy (VSFS, interface sensitive), infrared reflection absorption spectroscopy (IRAS, near-surface sensitive), and confocal Raman microspectroscopy (CRM, bulk sensitive). The VSFS selectively targeted the two-dimensional structures, IRAS followed the growth of three-dimensional corrosion products, and CRM could provide a laterally resolved chemical map on localized aggregates of zinc hydroxy acetate and ZnO with bulk character. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3479207] All rights reserved.

  • 218.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. IVL Swedish Environmental Research Institute, Sweden .
    Baresel, Christian
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Transport and fate of silver as polymer-stabilised nanoparticles and ions in a pilot wastewater treatment plant, followed by sludge digestion and disposal of sludge/soil mixtures: A case study2014Ingår i: Journal of Environmental Science and Health. Part A: Toxic/Hazardous Substances and Environmental Engineering, ISSN 1093-4529, E-ISSN 1532-4117, Vol. 49, nr 12, s. 1416-1424Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A case study of transport and changes in properties of polymer-stabilised Ag NPs is presented in this paper investigating their interaction in different treatment steps within a fully realistic pilot wastewater treatment plant (WWTP), in anaerobic digested sludge, and in soil/sludge mixtures. The fate of the same Ag NPs was tracked in these environments, hence taking the history of the Ag NPs into account. The results show that most of the Ag NPs end up in the sludge (80-100%), also after anaerobically digestion. Furthermore, the fraction of silver in the supernatant was very low after 48h incubation with silver-containing digested sludge mixed with different soil types. However, when Ag NPs were added directly to the sludge/soil mixture, soluble silver was present in the supernatant with sandy soil, but not with clayey soil. In all, generated findings show that risk assessments and toxicological studies of Ag NPs suspensions must take into account possible chemical and particle transformations upon environmental entry, as silver in general become less soluble when transported to WWTPs and interacting with sludge, and soil.

  • 219.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Ekvall, M. T.
    Hansson, L. -A
    Cedervall, T.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tungsten carbide nanoparticles in simulated surface water with natural organic matter: dissolution, agglomeration, sedimentation and interaction with Daphnia magna2017Ingår i: Environmental Science: Nano, ISSN 2051-8153, Vol. 4, nr 4, s. 886-894Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Even though anthropogenic nano-sized tungsten carbide nanoparticles (WC NPs) have been found in the environment, there are currently no investigations on their environmental fate. This work studies the interaction between natural organic matter (NOM) and WC NPs, as well as the potential uptake by the aquatic model organism Daphnia magna. We here show that the affinity between WC NPs and humic acid or dihydroxybenzoic acid (DHBA), which are model molecules of NOM, is very low with no observed surface adsorption. The lack of a stabilizing effect of these organic molecules, in combination with a relatively high effective density of WC NP agglomerates in humic acid, resulted in the substantial agglomeration and sedimentation of the WC NPs. A higher stability of the smaller sized WC NP agglomerates (&lt;150 nm) means that this fraction is mobile and can be transported to other settings, suggesting that this particle fraction should be considered in further studies. The dissolution of tungsten from WC NPs was continuous and the relatively slow dissolution rate (on the order of 0.03 mg m-2 h-1) implies that particle transport will not be severely limited from a dissolution perspective. Uptake of tungsten (dissolved tungsten and WC particles) by D. magna was observed although this did not induce any acute toxic effects.

  • 220.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Karlsson, Hanna L.
    Hedberg, Yolanda
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Blomberg, Eva
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. SP Technical Research Institute of Sweden, Sweden.
    Wallinder, Inger Odnevall
    The importance of extracellular speciation and corrosion of copper nanoparticles on lung cell membrane integrity2016Ingår i: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 141, s. 291-300Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Copper nanoparticles (Cu NPs) are increasingly used in various biologically relevant applications and products, e.g., due to their antimicrobial and catalytic properties. This inevitably demands for an improved understanding on their interactions and potential toxic effects on humans. The aim of this study was to investigate the corrosion of copper nanoparticles in various biological media and to elucidate the speciation of released copper in solution. Furthermore, reactive oxygen species (ROS) generation and lung cell (A549 type II) membrane damage induced by Cu NPs in the various media were studied. The used biological media of different complexity are of relevance for nanotoxicological studies: Dulbecco's modified eagle medium (DMEM), DMEM+ (includes fetal bovine serum), phosphate buffered saline (PBS), and PBS + histidine. The results show that both copper release and corrosion are enhanced in DMEM+, DMEM, and PBS + histidine compared with PBS alone. Speciation results show that essentially no free copper ions are present in the released fraction of Cu NPs in neither DMEM+, DMEM nor histidine, while labile Cu complexes form in PBS. The Cu NPs were substantially more membrane reactive in PBS compared to the other media and the NPs caused larger effects compared to the same mass of Cu ions. Similarly, the Cu NPs caused much more ROS generation compared to the released fraction only. Taken together, the results suggest that membrane damage and ROS formation are stronger induced by Cu NPs and by free or labile Cu ions/complexes compared with Cu bound to biomolecules.

  • 221.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Le Bozec, N.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Spatial distribution and formation of corrosion products in relation to zinc release for zinc sheet and coated pre-weathered zinc at an urban and a marine atmospheric condition2013Ingår i: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 64, nr 4, s. 300-308Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zinc release data from 5 years of unsheltered exposures in a marine and an urban site is compiled for different zinc material types. The thin surface treatment on zinc materials is gradually detached after approximately 2 years at both sites, revealing the pre-weathered zinc surface unprotected. This consequently increased the release rates of zinc from this surface, whereas the zinc runoff rate from the bare zinc sheet remained relatively stable. Raman studies on bare zinc sheet exposed for 5 years at the marine site revealed zinc oxide of varying crystalline nature and hydrozincite to appear localized and separated from each other.

  • 222.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Initial Atmospheric Corrosion of Zinc Exposed to Formic Acid, Investigated by in Situ Vibrational Sum Frequency Spectroscopy and Density Functional Theory Calculations2008Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, s. 2088-2095Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Vibrational sum frequency spectroscopy (VSFS) and ab initio density functional theory (DFT) calculations of formic acid on ZnO/Zn have been performed in order to understand the first step of atmospheric corrosion on zinc initiated by formic acid. In addition, infrared reflection absorption spectroscopy (IRAS) has been employed to complement the surface sensitive VSFS results to identify the corrosion products. Oxidized polycrystalline zinc samples were exposed to 120 ppb formic acid in either humid or dry Air where, the formic acid adsorption on ZnO/Zn is observed to have a low dependence on the humidity, as deduced by VSFS. Formate is formed on the surface in both dry and humid air and stabilized in configuration after about 90 min exposure in 120 ppb formic acid as seen in the VSFS results. This is evidenced by the occurrence of the CH and symmetric COO- vibrations of the formate ion. The DFT calculations support the VSFS results, showing a coordination of the formate to zinc ions without participation from water molecules.

  • 223.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Molecular in-situ observations of hydroxyl groups and ligand exchange during initial atmospheric corrosionManuskript (preprint) (Övrigt vetenskapligt)
  • 224.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Molecular structural information of the atmospheric corrosion of zinc studied by vibrational spectroscopy techniques: Part I. Experimental approachManuskript (preprint) (Övrigt vetenskapligt)
  • 225.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Molecular structural information of the atmospheric corrosion of zinc studied by vibrational spectroscopy techniques: Part II. Two and three dimensional growth of reaction products induced by formic and acetic acidManuskript (preprint) (Övrigt vetenskapligt)
  • 226.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära (stängd 20081231).
    Cimatu, Katherine
    Baldelli, Steven
    Adsorption and Structure of Octadecanethiol on Zinc Surfaces As Probed by SumFrequency Generation Spectroscopy, Imaging, and Electrochemical Techniques2007Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 111, nr 47, s. 17587-17596Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Octadecanethiol (ODT) adsorbed onto zinc has been studied with sum frequency generation (SFG), sum frequency generation imaging microscopy (SFG-IM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and electrical impedance spectroscopy (EIS) in order to investigate its corrosion protective ability and conformational ordering. SFG shows that ODT forms an ordered adsorbate on both reduced and oxidized zinc within short times after immersion in 1 mM ODT/ethanol solution. The corrosion protection, deduced by EIS, is also improved after immersion in the ODT solution. After longer immersion times, the corrosion protection decreases as well as the conformational order of the adsorbed ODT. Increasing the ODT concentration avoids this degradation with prolonged immersion time. The ODT is seen in the XPS spectra to adsorb to the reduced as well as the oxidized zinc by forming a Zn-S bond for both short and long immersion times. The SFG-IM completes the picture, showing a heterogeneous surface with areas corresponding to ordered ODT as well as disordered or uncovered regions. The density of adsorbed ODT after 24 h immersion time for both reduced and oxidized zinc was deduced from CV and was found to be approximately 6.7 x 10(-9) mol/cm(2).

  • 227.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Lowe, Troy A.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Wold, Susanna
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Ion selective electrodes are not suitable for measurements of silver ion concentrations in alkaline carbonate media2013Ingår i: Analytical Methods, ISSN 1759-9660, E-ISSN 1759-9679, Vol. 5, nr 4, s. 1068-1070Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An ion selective electrode (ISE) for determination of the labile silver ion concentration in carbonate containing solutions of pH 10 was seen to give incorrect results due to shifts in the Ag vertical bar Ag+ equilibrium. This drawback was not the case for the differential pulse anodic stripping voltammetry (DPASV) method.

  • 228.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Lundin, Maria
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Lowe, Troy
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Blomberg, Eva
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Wold, Susanna
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Interactions between surfactants and silver nanoparticles of varying charge2012Ingår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 369, nr 1, s. 193-201Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The interaction between silvernanoparticles (Ag NPs) of different surface charge and surfactants relevant to the laundry cycle has been investigated to understand changes in speciation, both in and during transport from the washing machine. Ag NPs were synthesized to exhibit either a positive or a negative surface charge in solution conditions relevant for the laundry cycle (pH 10 and pH 7). These particles were characterized in terms of size and surface charge and compared to commercially laser ablated Ag NPs. The surfactants included anionic sodium dodecylbenzenesulfonate (LAS), cationic dodecyltrimethylammoniumchloride (DTAC) and nonionic Berol 266 (Berol). Surfactant–Ag NP interactions were studied by means of dynamic light scattering, Raman spectroscopy, zeta potential, and Quartz Crystal Microbalance. Mixed bilayers of CTAB and LAS were formed through a co-operative adsorption process on positively charged Ag NPs with pre-adsorbed CTAB, resulting in charge reversal from positive to negative zeta potentials. Adsorption of DTAC on negatively charged synthesized Ag NPs and negatively charged commercial Ag NPs resulted in bilayer formation and charge reversal. Weak interactions were observed for nonionic Berol with all Ag NPs via hydrophobic interactions, which resulted in decreased zeta potentials for Berol concentrations above its critical micelle concentration. Differences in particle size were essentially not affected by surfactant adsorption, as the surfactant layer thicknesses did not exceed more than a few nanometers. The surfactant interaction with the Ag NP surface was shown to be reversible, an observation of particular importance for hazard and environmental risk assessments.

  • 229.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. IVL Swedish Environmental Research Institute, Stockholm, Sweden .
    Oromieh, Aidin Geranmayeh
    Kleja, Dan Berggren
    Odenevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Sorption and dissolution of bare and coated silver nanoparticles in soil suspensions-Influence of soil and particle characteristics2015Ingår i: Journal of Environmental Science and Health. Part A: Toxic/Hazardous Substances and Environmental Engineering, ISSN 1093-4529, E-ISSN 1532-4117, Vol. 50, nr 9, s. 891-900Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increasing use of silver nanoparticles (AgNPs) in consumer products triggers the need for investigations that improve the understanding of their chemical transformations upon environmental entry. Such knowledge provides crucial information for toxicological studies and risk assessments. Interactions with the soil compartment need to be explored as there are evident risks of the dispersion of both AgNPs and of released Ag ions/complexes present in wastewater-treated sludge that is distributed onto agricultural land. The dissolution and fractionation in solution of bare (AgNP-bare, noncoated) and coated AgNPs (AgNP-coat, stabilized with two nonionic surfactants, polyoxyethylene glycerol trioleate and Tween 20) were investigated after 4 and 48h in suspensions of one sandy and one clayey soil of different pHs (3.3, 5.2). Parallel experiments were performed with soil suspensions spiked with easily soluble AgNO3. Silver in the water phase was separated in a dissolved fraction (mainly Ag ions/complexes) and a particle fraction (mainly AgNP/agglomerates/Ag adsorbed on organic matter) by means of ultracentrifugation. Bare AgNPs were nonstable and dissolved to a significantly larger extent in the sandy soil mixture compared to coated AgNPs. The concentration of dissolved Ag (ions/complexes) in the water phase was similar in the case of bare AgNPs and AgNO3 (at pH 3 and 5.2) after 24h in sandy soil, which implies a high degree of dissolution of bare AgNPs (50-100%). In contrast, approximately 50% of the coated AgNPs remained in the water phase after 48h of equilibration in the sandy soil at pH 5.2. The clayey soil had a significantly higher sorption capacity of Ag compared with the sandy soil, as Ag in the case of coated AgNPs was only detected in the water phase of pH 5.2 (<1 % of added Ag). Ultracentrifugation was proven more efficient compared with microfiltration to separate the dissolved Ag fraction (ions/complexes) and the particle fraction (AgNPs/agglomerates) of the water phase. This fractionation is not a measure of any potential toxicity.

  • 230.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Skoglund, Sara
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Karlsson, Maria-Elisa
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Wold, Susanna
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Hedberg, Yolanda
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Sequential Studies of Silver Released from Silver Nanoparticles in Aqueous Media Simulating Sweat, Laundry Detergent Solutions and Surface Water2014Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 48, nr 13, s. 7314-7322Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    From an increased use of silver nanoparticles (Ag NPs) as an antibacterial in consumer products follows a need to assess the environmental interaction and fate of their possible dispersion and release of silver. This study aims to elucidate an exposure scenario of the Ag NPs potentially released from, for example, impregnated clothing by assessing the release of silver and changes in particle properties in sequential contact with synthetic sweat, laundry detergent solutions, and freshwater, simulating a possible transport path through different aquatic media. The release of ionic silver is addressed from a water chemical perspective, compared with important particle and surface characteristics. Released amounts of silver in the sequential exposures were significantly lower, approximately a factor of 2, than the sum of each separate exposure. Particle characteristics such as speciation (both of Ag ionic species and at the Ag NP surface) influenced the release of soluble silver species present on the surface, thereby increasing the total silver release in the separate exposures compared with sequential immersions. The particle stability had no drastic impact on the silver release as most of the Ag NPs were unstable in solution. The silver release was also influenced by a lower pH (increased release of silver), and cotransported zeolites (reduced silver in solution).

  • 231.
    Hedberg, Yolanda
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Environmental and health aspects of corrosion– importance of chemical speciation2010Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    During the last decades, the interest in corrosion of metals and alloys from an environmental and health perspective has increased rapidly as a consequence of stricter environmental and human exposure legislations, their extensive use as implant materials and an increasing understanding related to occupational and/or daily exposure to airborne particles. Corrosion-induced metal release, however, needs to be understood in detail and to include knowledge related to chemical speciation, i.e. the oxidation state, complexation and chemical form of released metals, parameters of high importance when considering toxicity.

    In this licentiate work, corrosion-induced metal runoff from roofing materials (copper, zinc, and chromium(III)-, and chromium(VI) surface treated galvanized steel) has been investigated from an environmental perspective with focus on chemical speciation of released metals (Papers I-II). From these papers it was evident that the total concentration measured in the runoff water is not sufficient for any environmental risk assessment. The environmental fate including changes in chemical speciation and hence metal precipitation has to be considered. For example, it was shown that the copper concentration decreased by three orders of magnitude already in the internal drainage system of a shopping centre with a copper roof, to a concentration lower than storm water collected from a nearby parking space (Paper I). Also, speciation measurements can explain corrosion, metal release and surface processes of chromium surface treated galvanized steel at different sites (urban and marine). Any environmental risk assessment has to be done by considering all metal species released, and compared with ecotoxic values. For example, when most chromium(VI) (the most toxic species) was released, significantly less zinc was released at the same time which decreased the overall ecotoxicity of the runoff water significantly (Paper II).

    When assessing environmental risks by standard laboratory tests, it is important to understand all mechanisms which are possibly influenced by individual experimental parameters and which often are different for different test substances. Some metals released, as seen in the case of iron, may precipitate with time and be pH-, solution- and buffering dependent. This behavior can lead to strongly underestimated measured metal concentrations (Paper III).

    When particles of metals or alloys are to be investigated (Papers III-VI), it is essential to conduct a thorough particle characterization, since the surface properties cannot be defined. In addition, the surface properties (oxide layer properties) change with varying particle size (Paper VI) and with other experimental parameters such as dispersion (Paper VI).

    All iron-, and chromium-based particles investigated (Papers III-VI) revealed large differences between alloy particles and pure metals. Particles of pure iron and nickel released significantly more metals compared with particles of the investigated alloys, whereas particles of pure chromium released less metals compared with the alloys. Particles of stainless steel (AISI 316L), ferro-chromium and ferro-silicon-chromium released very low amounts of metals (Papers III-VI). The released quantity increased with increased acidity (Papers III-VI) and also in the presence of complexing agents (ongoing research). The manufacturing process is of high importance, as observed for stainless steel particles when compared with a side product from stainless steel production with similar composition that released significantly more metals (Paper III). Particles of metal oxides, i.e. chromium(III)oxide and iron(II,III)oxide, released very low amounts of metals due to their thermodynamic stability.

    Ongoing research activities focus on the specific influence of complexing agents and proteins on the metal release process from massive sheet and particles of metals and alloys. The applicability and the possibility to use different analytical tools are investigated and elaborated for small-sized particles. A detailed understanding of the correlation between material and particle characteristics, the metal release process, the chemical speciation in interaction with proteins and/or cells, and the particle/cell interaction is essential to enable any correlation between material/particle characteristics and toxicity.

    The aim of this licentiate summary is – in contrast to the six included scientific papers – to explain the importance of chemical speciation for corrosion processes from a health and environmental perspective in a popular way to reach a broad non-academic audience. The summary is hence written as a guidance document for stakeholders and the regulatory community working with environmental and health risk assessment.

  • 232.
    Hedberg, Yolanda
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Stainless Steel in Biological Environments – Relation between Material Characteristics, Surface Chemistry and Toxicity2012Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Triggered by the regulatory need of the industry to demonstrate safe use of their alloy products from an environmental and health perspective, and by the significant lack of metal release data and its correlation to material and surface characteristics for iron- and chromium-based alloys, a highly interdisciplinary in-depth research effort was undertaken to assess the relation between material/surface characteristics and toxicity with main emphasis on stainless steel alloys. This thesis focuses predominantly on studies made on AISI 316L both as massive sheet and as powder particles, but includes also results for other stainless steel grades and reference metals and metal oxides.

     

    The work comprises multi-analytical bulk and surface characterizations combined with particle characterizations and corrosion investigations, all correlated with in-depth kinetic metal release (bioaccessibility) studies as a function of route of manufacture, powder particle characteristics, surface finish, stainless steel grade, solution composition, pH, acidity and complexation capacity, as well as the presence of proteins. Speciation (chemical form) measurements were in addition conducted of released chromium, and of metal species in the surface oxide. Protein interactions were investigated in terms of adsorption, protein-metal complexation both at the surface and in solution, and the relative strength of protein-stainless steel surface interaction was addressed. In vitro and in vivo toxicological studies were conducted for the same inert-gas-atomized 316L powder sized < 4µm.

     

    Bulk and surface oxide properties, such as phase, structure, morphology, chemical and electrochemical stability, protein-surface interactions, bioavailability of released metals, were all clearly evident to largely influence the metal release process and any induced toxicity. The route of manufacture was shown to strongly influence the bulk and surface oxide characteristics of stainless steel powders, hence also their electrochemical and catalytic properties, as well as the release/dissolution of metals from the powders (Papers VIII, XIII, XIV-XVII). The release of metals from both stainless steel sheets and powders was in general low compared to pure iron or nickel metal, and highly dependent on bulk and surface characteristics, the composition, complexation capacity and buffering capacity (and pH) of the solution, as well as on many experimental factors including time and sonication (Papers VI, VIII, XI, and XVII).

     

    Surface-protein interactions strongly enhanced the release of alloy constituents (Papers IX, XI, and XVII). Iron was preferentially released (manganese in the case of inert-gas-atomized stainless steel powders) (Papers VIII, XI, and XVII). Protein-stainless steel surface interactions were most probably governed by chemisorption at given experimental conditions (Papers XI-XII). A strong protein-adsorption was evident for all stainless steel surfaces investigated, independent of protein charge, size or structure (Paper IX). Protein-metal complexes were formed both at the surface and in solution (Papers X-XII). Differences in protein charge and type resulted in varying degrees of interaction with differences in the extent of enhanced metal release as a consequence (Papers XI-XII). The inert-gas-atomized stainless steel powder sized <4 µm induced neither any significant increase of lysis of erythrocytes (rupture of red blood cells) nor any cytotoxicity, but resulted in a slight DNA damage in in vitro toxicity measurements (Paper VI). No adverse effects were however observed in an in vivo 28-day repeated-dose inhalation study on rats using the same powder (Paper VII).

     

    The most important bulk, surface, particle, and experimental factors governing the bioaccessibility properties of stainless steel were identified and mechanistically elucidated. Detailed knowledge of all factors is essential for accurate hazard or risk assessment of metal alloys and enables read-across possibilities with materials of the same or similar characteristics. However, in cases where data is different from known systems for one factor or more, bioaccessibility data should be generated before any risk assessment is made.

  • 233.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Gustafsson, Johanna
    Unit for Analytical Toxicology, Department of Biosciences and Nutrition, Novum, Karolinska Insitutet, SE-141 86 Huddinge, Stockholm, Sweden.
    Karlsson, Hanna L.
    Unit for Analytical Toxicology, Department of Biosciences and Nutrition, Novum, Karolinska Insitutet, SE-141 86 Huddinge, Stockholm, Sweden.
    Möller, Lennart
    Unit for Analytical Toxicology, Department of Biosciences and Nutrition, Novum, Karolinska Insitutet, SE-141 86 Huddinge, Stockholm, Sweden.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Bioaccessibility, bioavailability and toxicity of commercially relevant iron- and chromium-based particles: in vitro studies with an inhalation perspective2010Ingår i: Particle and Fibre Toxicology, ISSN 1743-8977, E-ISSN 1743-8977, Vol. 7, nr 23Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background

    Production of ferrochromium alloys (FeCr), master alloys for stainless steel manufacture, involves casting and crushing processes where particles inevitably become airborne and potentially inhaled. The aim of this study was to assess potential health hazards induced by inhalation of different well-characterized iron- and chromium-based particles, i.e. ferrochromium (FeCr), ferrosiliconchromium (FeSiCr), stainless steel (316L), iron (Fe), chromium (Cr), and chromium(III)oxide (Cr2O3), in different size fractions using in vitro methods. This was done by assessing the extent and speciation of released metals in synthetic biological medium and by analyzing particle reactivity and toxicity towards cultured human lung cells (A549).

    Results

    The amount of released metals normalized to the particle surface area increased with decreasing particle size for all alloy particles, whereas the opposite situation was valid for particles of the pure metals. These effects were evident in artificial lysosomal fluid (ALF) of pH 4.5 containing complexing agents, but not in neutral or weakly alkaline biological media. Chromium, iron and nickel were released to very low extent from all alloy particles, and from particles of Cr due to the presence of a Cr(III)-rich protective surface oxide. Released elements were neither proportional to the bulk nor to the surface composition after the investigated 168 hours of exposure. Due to a surface oxide with less protective properties, significantly more iron was released from pure iron particles compared with the alloys. Cr was predominantly released as Cr(III) from all particles investigated and was strongly complexed by organic species of ALF. Cr2O3 particles showed hemolytic activity, but none of the alloy particles did. Fine-sized particles of stainless steel caused however DNA damage, measured with the comet assay after 4 h exposure. None of the particles revealed any significant cytotoxicity in terms of cell death after 24 h exposure.

    Conclusion

    It is evident that particle and alloy characteristics such as particle size and surface composition are important aspects to consider when assessing particle toxicity and metal release from alloy particles compared to pure metal particles. Generated results clearly elucidate that neither the low released concentrations of metals primarily as a result of protective and poorly soluble surface oxides, nor non-bioavailable chromium complexes, nor the particles themselves of occupational relevance induced significant acute toxic response, with exception of DNA damage from stainless steel.

  • 234.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Hedberg, Jonas
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Isaksson, Sara
    KTH, Skolan för kemivetenskap (CHE).
    Mei, Nanxuan
    KTH, Skolan för kemivetenskap (CHE).
    Blomberg, Eva
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Wold, S.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Nanoparticles of WC-Co, WC, Co and Cu of relevance for traffic wear particles – Particle stability and reactivity in synthetic surface water and influence of humic matter2017Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 224, s. 275-288Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Studded tyres made of tungsten carbide cobalt (WC-Co) are in the Northern countries commonly used during the winter time. Tungsten (W)-containing nano- and micron-sized particles have been detected close to busy roads in several European countries. Other typical traffic wear particles consist of copper (Cu). The aims of this study were to investigate particle stability and transformation/dissolution properties of nanoparticles (NPs) of WC-Co compared with NPs of tungsten carbide (WC), cobalt (Co), and Cu. Their physicochemical characteristics (primarily surface oxide and charge) are compared with their extent of sedimentation and metal release in synthetic surface water (SW) with and without two different model organic molecules, 2,3- and 3,4-dihydroxybenzoic acid (DHBA) mimicking certain sorption sites of humic substances, for time periods up to 22 days. The WC-Co NPs possessed a higher electrochemical and chemical reactivity in SW with and without DHBA molecules as compared with NPs of WC, Co, and Cu. Co was completely released from the WC-Co NPs within a few hours of exposure, although it remained adsorbed/bonded to the particle surface and enabled the adsorption of negatively charged DHBA molecules, in contrast with the WC NPs (no adsorption of DHBA). The DHBA molecules were found to rapidly adsorb on the Co and Cu NPs. The sedimentation of the WC and WC-Co NPs was not influenced by the presence of the 2,3- or 3,4-DHBA molecules. A slight influence (slower sedimentation) was observed for the Co NPs, and a strong influence (slower sedimentation) was observed for the Cu NPs in SW with 2,3-DHBA compared with SW alone. The extent of metal release increased in the order: WC < Cu < Co < WC-Co NPs. All NPs released more than 1 wt-% of their metal total mass. The release from the Cu NPs was most influenced by the presence of DHBA molecules.

  • 235.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Hedberg, Jonas
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Liu, Yi
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Complexation- and ligand-induced metal release from 316L particles: importance of particle size and crystallographic structure2011Ingår i: Biometals, ISSN 0966-0844, E-ISSN 1572-8773, Vol. 24, nr 6, s. 1099-1114Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Iron, chromium, nickel, and manganese released from gas-atomized AISI 316L stainless steel powders (sized < 45 and < 4 mu m) were investigated in artificial lysosomal fluid (ALF, pH 4.5) and in solutions of its individual inorganic and organic components to determine its most aggressive component, elucidate synergistic effects, and assess release mechanisms, in dependence of surface changes using atomic absorption spectroscopy, Raman, XPS, and voltammetry. Complexation is the main reason for metal release from 316L particles immersed in ALF. Iron was mainly released, while manganese was preferentially released as a consequence of the reduction of manganese oxide on the surface. These processes resulted in highly complexing media in a partial oxidation of trivalent chromium to hexavalent chromium on the surface. The extent of metal release was partially controlled by surface properties (e.g., availability of elements on the surface and structure of the outermost surface) and partially by the complexation capacity of the different metals with the complexing agents of the different media. In general, compared to the coarse powder (< 45 mu m), the fine (< 4 mu m) powder displayed significantly higher released amounts of metals per surface area, increased with increased solution complexation capacity, while less amounts of metals were released into non-complexing solutions. Due to the ferritic structure of lower solubility for nickel of the fine powder, more nickel was released into all solutions compared with the coarser powder.

  • 236.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Hedberg, Jonas
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Particle characteristics and metal release from natural rutile (TiO2) and zircon particles in synthetic body fluids2012Ingår i: Journal of Biomaterials and Nanobiotechnology, ISSN 2158-7027, E-ISSN 2158-7043, Vol. 3, nr 1, s. 37-49Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Titanium oxide (rutile, TiO2) and zircon (ZrSiO4), known insoluble ceramic materials, are commonly used for coatings of implant materials. We investigate the release of zirconium, titanium, aluminum, iron, and silicon from different micron-sized powders of 6 powders of natural rutile (TiO2) and zircon (ZrSiO4) from a surface perspective. The investiga- tion includes five different synthetic body fluids and two time periods of exposure, 2 and 24 hours. The solution chemi- cals rather than pH are important for the release of zirconium. When exceeding a critical amount of aluminum and sili- con in the surface oxide, the particles seem to be protected from selective pH-specific release at neutral or weakly alka- line pH. The importance of bulk and surface composition and individual changes between different kinds of the same material is elucidated. Changes in material properties and metal release characteristics with particle size are presented for zircon.

  • 237.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. Karolinska Institutet, Sweden.
    Herting, Gunilla
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Latvala, S.
    Elihn, K.
    Karlsson, H. L.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Surface passivity largely governs the bioaccessibility of nickel-based powder particles at human exposure conditions2016Ingår i: Regulatory toxicology and pharmacology, ISSN 0273-2300, E-ISSN 1096-0295, Vol. 81, s. 162-170Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The European chemical framework REACH requires that hazards and risks posed by chemicals, including alloys and metals, are identified and proven safe for humans and the environment. Therefore, differences in bioaccessibility in terms of released metals in synthetic biological fluids (different pH (1.5–7.4) and composition) that are relevant for different human exposure routes (inhalation, ingestion, and dermal contact) have been assessed for powder particles of an alloy containing high levels of nickel (Inconel 718, 57 wt% nickel). This powder is compared with the bioaccessibility of two nickel-containing stainless steel powders (AISI 316L, 10–12% nickel) and with powders representing their main pure alloy constituents: two nickel metal powders (100% nickel), two iron metal powders and two chromium metal powders. X-ray photoelectron spectroscopy, microscopy, light scattering, and nitrogen absorption were employed for the particle and surface oxide characterization. Atomic absorption spectroscopy was used to quantify released amounts of metals in solution. Cytotoxicity (Alamar blue assay) and DNA damage (comet assay) of the Inconel powder were assessed following exposure of the human lung cell line A549, as well as its ability to generate reactive oxygen species (DCFH-DA assay). Despite its high nickel content, the Inconel alloy powder did not release any significant amounts of metals and did not induce any toxic response. It is concluded, that this is related to the high surface passivity of the Inconel powder governed by its chromium-rich surface oxide. Read-across from the pure metal constituents is hence not recommended either for this or any other passive alloy.

  • 238.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Karlsson, M. -E
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Wei, Z.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Znidarsic, M.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Hedberg, Jonas
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Interaction of Albumin and Fibrinogen with Stainless Steel: Influence of Sequential Exposure and Protein Aggregation on Metal Release and Corrosion Resistance2017Ingår i: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 73, nr 12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Corrosion and metal release mechanisms of the biomedical stainless steel grade Type 316L are at human-relevant biological conditions not fully understood. This study focuses on its corrosion properties and release of iron (Fe), chromium (Cr), manganese (Mn), and nickel (Ni) into simulated physiological solutions at pH 7.4 in the presence of proteins. Parallel studies were performed on stainless steel Type 303 containing a substantial amount of MnS inclusions. Metal release studies were performed in phosphate buffered saline (PBS) for 4 h and 24 h at 37 degrees C with or without different concentrations of bovine serum albumin (BSA), fibrinogen from bovine plasma (Fbn), or mixtures of the same. Studies were in addition performed after 1, 4, 6, and 24 h in solutions that were partially replenished after 5 h in order to investigate whether any Vroman effect (exchange of adsorbed proteins by proteins of higher binding affinity) could influence the extent of released metals in solution. This was performed at physiological concentrations of BSA (40 g/L) and Fbn (2.67 g/L) in PBS, and for reference solutions of PBS, PBS with 40 g/L BSA, and PBS with 2.67 g/L Fbn. Changes in open-circuit potential and linear polarization resistance were investigated for the same conditions. After exposure, the exposed surfaces were rinsed and investigated ex situ by means of x-ray photoelectron spectroscopy and infrared reflection absorption spectroscopy. Metal-protein complexation-induced metal release mechanisms were found to be most pronounced for Type 316L and the release of Fe, Cr, and Ni. Fibrinogen adsorbed differently onto Type 303 (thicker conformation of adsorbed proteins) as compared with Type 316L and occasionally induced corrosion events for Type 303. Mn was mostly released from inclusions present in the Type 303 alloy, most probably via non-electrochemical mechanisms. A Vroman effect was observed for both grades. A significant extent of precipitation of metal-rich protein aggregates influenced the metal release measurements in solution and resulted in an underestimation of the total amount of released metals from the stainless steel grades.

  • 239.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Karlsson, Maria-Elisa
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Blomberg, Eva
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. SP Technical Research Institute of Sweden, Sweden.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Hedberg, Jonas
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Correlation between surface physicochemical properties and the release of iron from stainless steel AISI 304 in biological media2014Ingår i: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 122, s. 216-222Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Stainless steel is widely used in biological environments, for example as implant material or in food applications, where adsorption-controlled ligand-induced metal release is of importance from a corrosion, health, and food safety perspective. The objective of this study was to elucidate potential correlations between surface energy and wettability of stainless steel surfaces and the release of iron in complexing biological media. This was accomplished by studying changes in surface energies calculated from contact angle measurements, surface oxide composition (X-ray photoelectron spectroscopy), and released iron (graphite furnace atomic absorption spectroscopy) for stainless steel grade AISI 304 immersed in fluids containing bovine serum albumin or citric acid, and non-complexing fluids such as NaCl, NaOH, and HNO3. It was shown that the surface wettability and polar surface energy components were all influenced by adventitious atmospheric carbon (surface contamination of low molecular weight), rather than differences in surface oxide composition in non-complexing solutions. Adsorption of both BSA and citrate, which resulted in ligand-induced metal release, strongly influenced the wettability and the surface energy, and correlated well with the measured released amount of iron.

  • 240.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Karlsson, Oskar
    Szakalos, Peter
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Wallinder, Inger Odnevall
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Ultrafine 316 L stainless steel particles with frozen-in magnetic structures characterized by means of electron backscattered diffraction2011Ingår i: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 65, nr 14, s. 2089-2092Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electron Backscatter Diffraction (EBSD) studies clearly revealed a different crystallographic structure of the smallest particle size fraction of gas-atomized AISI 316 L stainless steel powder (<4 mu m) compared with larger sized fractions of the same powder (<45 mu m). Despite similar chemical compositions, the predominating structure of the smallest particle size fraction was ferritic (i.e., has ferromagnetic properties) whereas the larger sized particle fractions and massive 316 L revealed an expected austenitic and non-magnetic structure. From these findings, it follows that direct magnetic separation can be applied to separate very fine sized particles. These structural differences explain previously observed dissimilarities from corrosion and metal release perspectives.

  • 241.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Killian, Manuela S.
    Department of Materials Science and Engineering 4, Chair for Surface Science and Corrosion, Friedrich-Alexander-University of Erlangen-Nuremberg, Martensstr.7, 91058 Erlangen, Germany.
    Blomberg, Eva
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Virtanen, Sannakaisa
    Department of Materials Science and Engineering 4, Chair for Surface Science and Corrosion, Friedrich-Alexander-University of Erlangen-Nuremberg, Martensstr.7, 91058 Erlangen, Germany.
    Schmuki, Patrik
    Department of Materials Science and Engineering 4, Chair for Surface Science and Corrosion, Friedrich-Alexander-University of Erlangen-Nuremberg, Martensstr.7, 91058 Erlangen, Germany.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Interaction of bovine serum albumin and lysozyme with stainless steel studied by time of flight secondary ion mass spectrometry and x-ray photoelectron spectroscopy2012Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 28, nr 47, s. 16306-16317Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An in-depth mechanistic understanding of the interaction between stainless steel surfaces and proteins is essential from a corrosion and protein-induced metal release perspective when stainless steel is used in surgical implants and in food applications. The interaction between lysozyme (LSZ) from chicken egg white and bovine serum albumin (BSA) and AISI 316L stainless steel surfaces was studied ex situ by means of X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) after different adsorption time periods (0.5, 24, and 168 h). The effect of XPS measurements, storage (aging), sodium dodecyl sulfate (SDS), and elevated temperature (up to 200 °C) on the protein layers, as well as changes in surface oxide composition, were investigated. Both BSA and LSZ adsorption induced an enrichment of chromium in the oxide layer. BSA induced significant changes to the entire oxide, while LSZ only induced a depletion of iron at the utmost layer. SDS was not able to remove preadsorbed proteins completely, despite its high concentration and relatively long treatment time (up to 36.5 h), but induced partial denaturation of the protein coatings. High-temperature treatment (200 °C) and XPS exposure (X-ray irradiation and/or photoelectron emission) induced significant denaturation of both proteins. The heating treatment up to 200 °C removed some proteins, far from all. Amino acid fragment intensities determined from ToF-SIMS are discussed in terms of significant differences with adsorption time, between the proteins, and between freshly adsorbed and aged samples. Stainless steel–protein interactions were shown to be strong and protein-dependent. The findings assist in the understanding of previous studies of metal release and surface changes upon exposure to similar protein solutions.

  • 242.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Liden, Carola
    Wallinder, Inger Odnevall
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Corrigendum to "Correlation between bulk- and surface chemistry of Cr-tanned leather and the release of Cr(III) and Cr(VI)" [J. Hazard. Mater. 280, (2014), 654-661], doi :10.1016/j.jhazmat.2014.08.0612015Ingår i: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 285, s. 542-542Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    [No abstract available]

  • 243.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Linhardt, P.
    Wallinder, Inger Odnevall
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Electrochemical testing of sub-micron sized stainless steel particles2011Ingår i: Eur. Corros. Congr., EUROCORR, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Electrochemical testing of corrosion properties such as passivity is well established for massive stainless steels but difficult to conduct for sub-micron particles. These particles need to be attached at an inert electrode surface without changing their corrosion properties. In order to electrochemically investigate passivity properties for AISI 316L stainless steel particles sized less than 45 and 4 μm, respectively, several experimental set-ups have been explored. A paraffin impregnated graphite electrode was found to be the most suitable, reliable and reproducible set-up. Differently produced particles (gas- and water-atomized) of varying size were investigated. In addition, the effect of artificial passivation was explored. Chloride-containing media and media of relevance for human exposure, such as artificial body fluids, were used as electrolytes. For comparison, measurements were also carried out with massive 316L stainless steel. The passive properties of stainless steel particles were shown to be significantly different compared to massive 316L. All particles revealed a significantly higher open circuit potential compared with massive 316L and no passivity breakdown up to 1.2 V vs. Ag/AgCl reference electrode in neutral chloride-rich solutions was observed. No or few transient current peaks related to corrosion processes were observed in neutral solutions, but such events were numerous in aggressive acidic solutions such as 0.7% HCl. Particle dissolution effects were dependent on the particle manufacturing process, on artificial passivation, and on particle size. The relatively high open circuit potential determined for these particles (up to 0.6 V vs. Ag/AgCl in neutral saline solution) is assumed to be the consequence of manganese oxides identified on the surface of the 316L particles, which are not present on the surface of massive 316L. The electrochemical results are compared with data from parallel studies assessing metal release and surface compositional properties of the 316L particles.

  • 244.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Lundin, Maria
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Jacksén, Johan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Analytisk kemi.
    Emmer, Åsa
    KTH, Skolan för kemivetenskap (CHE), Kemi, Analytisk kemi.
    Blomberg, Eva
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Wallinder, Inger Odnevall
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Chromium-protein complexation studies by adsorptive cathodic stripping voltammetry and MALDI-TOF-MS2012Ingår i: Journal of Applied Electrochemistry, ISSN 0021-891X, E-ISSN 1572-8838, Vol. 42, nr 5, s. 349-358Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A methodology using stripping voltammetry has been elaborated to enable sensitive and reliable protein-chromium complexation measurements. Disturbing effects caused by adsorption of proteins on the mercury electrode were addressed. At low concentrations of proteins (< 60-85 nM), chromium-protein complexation measurements were possible. Chromium(VI) complexation was quantitatively determined using differently sized, charged, and structured proteins: serum albumin (human and bovine), lysozyme, and mucin. Generated results showed a strong relation between complexation and protein size, concentration, and the number of amino acids per protein mass. Complexation increased nonlinearly with increasing protein concentrations. The nature of this complexation was based on weak interactions judged from combined results with MALDI-TOF-MS and adsorptive cathodic stripping voltammetry.

  • 245.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Mazinanian, Neda
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Metal release from stainless steel powders and massive sheets - comparison and implication for risk assessment of alloys2013Ingår i: Environmental Sciences: Processes and Impacts, ISSN 2050-7887, Vol. 15, nr 2, s. 381-392Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Industries that place metal and alloy products on the market are required to demonstrate them being safe for all intended uses, and that any risks to humans, animals or the environment are adequately controlled. This requires reliable and robust in-vitro test procedures. The aim of this study is to compare the release of alloy constituents from stainless steel powders of different grades (focus on AISI 316L) and production routes into synthetic body fluids with the release of the same metals from massive sheet in relation to material and surface characteristics. The comparison is justified by the fact that the difference between massive surfaces and powders from a metal release/dissolution and surface perspective is not clearly elucidated within current legislations. Powders and abraded and aged (24 h) massive sheets were exposed to synthetic solutions of relevance for biological settings and human exposure routes, for periods up to one week. Concentrations of released iron, chromium, nickel, and manganese in solution were measured, and the effect of solution pH, acidity, complexation capacity, and proteins elucidated in relation to surface oxide composition and its properties. Implications for risk assessments based on in-vitro metal release data from alloys are elucidated.

  • 246.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Midander, Klara
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Size matters: Mechanism of metal release from 316L stainless steel particles is governed by size-dependent properties of the surface oxide2014Ingår i: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 122, s. 223-226Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Size-dependent health aspects due to exposure to micro- or nano-sized particles can only be fully understood if their physicochemical properties are well characterized. The aim of this study was to explain the process of metal release from well-characterized inert gas atomized stainless steel 316L particles, sized < 4 gm (fine) and < 45 gm (coarse), in aggressive environments of relevance for inhalation and cellular uptake. This was accomplished by correlating new results from real-time metal release measurements with particle- and surface oxide characteristics. In simulated biological media with complexing properties, a complexation (ligand)-induced dissolution mechanism is dominating the metal release from fine 316L particles (having a homogeneous and amorphous Mn-rich surface oxide due to rapid cooling). At similar conditions, the coarse 316L particles show a metal release mechanism dominated by fast dissolution of surface oxide nanoparticles (rich in Mn, Fe, and some S), acting as initiation sites for metastable pitting corrosion.

  • 247.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Midander, Klara
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Particles, sweat, and tears: A comparative study on bioaccessibility of ferrochromium alloy and stainless steel particles, the pure metals and their metal oxides, in simulated skin and eye contact2010Ingår i: Integrated Environmental Assessment and Management, ISSN 1551-3777, E-ISSN 1551-3793, ISSN 1551-3793, Vol. 6, nr 3, s. 456-468Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ferrochromium alloys are manufactured in large quantities and placed on the global market for use as master alloys (secondary raw materials), primarily for stainless steel production. Any potential human exposure to ferrochromium alloy particles is related to occupational activities during production and use, with 2 main exposure routes, dermal contact and inhalation and subsequent digestion. Alloy and reference particles exposed in vitro in synthetic biological fluids relevant for these main exposure routes have been investigated in a large research effort combining bioaccessibility; chemical speciation; and material, surface, and particle characteristics. In this paper, data for the dermal exposure route, including skin and eye contact, will be presented and discussed. Bioaccessibility data have been generated for particles of a ferrochromium alloy, stainless steel grade AISI 316L, pure Fe, pure Cr, iron(II,III)oxide, and chromium(III)oxide, upon immersion in artificial sweat (pH 6.5) and artificial tear (pH 8.0) fluids for various time periods. Measured released amounts of Fe, Cr, and Ni are presented in terms of average Fe and Cr release rates and amounts released per amount of particles loaded. The results are discussed in relation to bulk and surface composition of the particles. Additional information, essential to assess the bioavailability of Cr released, was generated by determining its chemical speciation and by providing information on its complexation and oxidation states in both media investigated. The effect of differences in experimental temperature, 30 °C and 37 °C, on the extent of metal release in artificial sweat is demonstrated. Iron was the preferentially released element in all test media and for all time periods and ironcontaining particles investigated. The extent of metal release was highly pH dependent and was also dependent on the medium composition. Released amounts of Cr and Fe were very low (close to the limit of detection, <0.008% of particles released or dissolved as iron or chromium) for the alloy particles (ferrochromium alloy and stainless steel), the pure Cr particles, and the metal oxide particles. The released fraction of Cr (Cr/[Cr + Fe]) varied with the material investigated, the test medium, and the exposure time and cannot be predicted from either the bulk or the surface composition. Chromium was released as noncomplexed Cr(III) and in addition in very low concentrations (<3 mg/L). Nickel released was under the limit of detection (0.5 mg/L), except for ultrafine stainless steel particles (<10 mg/L). It is evident that media chemistry and material properties from a bulk and surface perspective, as well as other particle characteristics, and the chemical speciation of released metals have to be considered when assessing any potential hazard or risk induced by sparingly soluble metal or alloy particles.

  • 248.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Norell, Mats
    Materials and Manufacturing Technology, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Hedberg, Jonas
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Szakálos, Peter
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Linhardt, Paul
    Institute for Chemical Technologies and Analytics (CTA), Vienna University of Technology, Getreidemarkt 9/164, A-1060 Vienna, Austria.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Surface characterisation of fine inert-gas- and water-atomised stainless steel 316L powders - formation of thermodynamically unstable surface oxide phases2013Ingår i: Powder Metallurgy, ISSN 0032-5899, E-ISSN 1743-2901, Vol. 56, nr 2, s. 158-163Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New insights are presented on the speciation of surface oxide phases on fine inert gas atomised (GA, <45 and <4 mu m) and water atomised (WA, <45 mu m) stainless steel AISI 316L powders. X-ray photoelectron and Auger electron spectroscopy, scanning electron microscopy, Raman spectroscopy, and cyclic voltammetry were applied for the characterisation. Oxidised manganese was strongly enriched in the outermost surface oxide of the GA powders (13 and 47 wt-%), an effect increasing with reduced particle size. Manganese and sulphur were enriched in oxide nanoparticles on the surface. Oxidised silicon (59 wt-%) was enriched on the WA powder surface. Tri-or tetravalent manganese oxides were observed on the GA particles in addition to alpha-Fe2O3, and Cr2O3. The oxide of the WA powder revealed in addition the likely presence of a silicate rich phase, mainly consisting of tetravalent Si, di- and/or trivalent Fe, and hexavalent Cr, which was confirmed not present as chromate.

  • 249.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Norell, Mats
    Materials and Manufacturing Technology, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Linhardt, Paul
    Institute for Chemical Technologies and Analytics (CTA), Vienna University of Technology, Getreidemarkt 9/164, A-1060 Vienna, Austria.
    Bergqvist, Hans
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik (Stängd 20120101), Funktionella material, FNM (Stängd 20120101).
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Influence of Surface Oxide Characteristics and Speciation on Corrosion, Electrochemical Properties and Metal Release of Atomized 316L Stainless Steel Powders2012Ingår i: International Journal of Electrochemical Science, ISSN 1452-3981, E-ISSN 1452-3981, Vol. 7, nr 12, s. 11655-11677Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Surface oxide characteristics of powder particles are important to consider for any toxicological risk assessment based on in-vitro or in-vivo tests. This study focuses on a multi-analytical approach (X-ray photoelectron spectroscopy, Auger electron spectroscopy, scanning- and transmission electron microscopy, and different electrochemical techniques) for in-depth characterization of surface oxides of inert-gas-atomized (GA) AISI 316L stainless steel powder, compared with massive sheet and a water-atomized (WA) 316L powder. Implications of differences in surface oxide phases and their surface distribution on corrosion, electrochemical properties and metal release are systematically discussed. Cr was enriched in an inner surface layer for both GA powders, with Mn and S enriched in the outermost surface oxide. The surface oxide was 2-5 nm thick for both GA powder size fractions, amorphous for the GA powder sized <4 μm and partially crystalline for the powder sized <45 μm. A strong ennoblement, i.e. positive shift in open circuit potential, of up to 800 mV, depending on solution, was observed for the GA powders. This ennoblement was induced by catalytic oxygen reduction properties of tri- or tetravalent Mn-oxides, not present on the massive sheet or WA powder. In contrast to the predominant presence of a trivalent Cr-oxide in the surface oxide of the GA powder particles, the WA<45μm powder revealed oxidized Cr, most probably present in its hexavalent state (not chromate), within a silicate-rich surface oxide. This study clearly shows that the surface oxide composition and speciation of differently sized GA and WA powders are unique (strongly connected to the atomization process) and of large importance for their pitting corrosion and metal release properties. For the GA<45μm powder, Mn-rich oxide nanoparticles were proposed to account for its higher pitting corrosion susceptibility, a more stable surface ennoblement, and a shift of the MnO2 oxidation/reduction peaks in the cyclic voltammogram, compared with the GA particles sized <4μm. The thermodynamically unstable ferritic structure of the small sized particle fraction (GA <4μm), despite an austenitic composition, revealed a higher pitting corrosion susceptibility and higher nickel release compared with the austenitic particle fraction of the GA <45 μm powder.

  • 250.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Metal release and speciation of released chromium from a biomedical CoCrMo alloy into simulated physiologically relevant solutions2014Ingår i: Journal of Biomedical Materials Research. Part B - Applied biomaterials, ISSN 1552-4973, E-ISSN 1552-4981, Vol. 102, nr 4, s. 693-699Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The objective of this study was to investigate the extent of released Co, Cr(III), Cr(VI), and Mo from a biomedical high-carbon CoCrMo alloy exposed in phosphate-buffered saline (PBS), without and with the addition of 10 mu M H2O2 (PBS + H2O2), and 10 g L-1 bovine serum albumin (PBS + BSA) for time periods up to 28 days. Comparative studies were made on AISI 316L for the longest time period. No Cr(VI) release was observed for any of the alloys in either PBS or PBS + H2O2 at open-circuit potential (no applied potential). However, at applied potentials (0.7 V vs. Ag/AgCl), Cr was primarily released as Cr(VI). Co was preferentially released from the CoCrMo alloy at no applied potential. As a consequence, Cr was enriched in the utmost surface oxide reducing the extent of metal release over time. This passivation effect was accelerated in PBS + H2O2. As previously reported for 316L, BSA may also enhance metal release from CoCrMo. However, this was not possible to verify due to the precipitation of metal-protein complexes with reduced metal concentrations in solution as a consequence. This was particularly important for Co-BSA complexes after sufficient time and resulted in an underestimation of metals in solution.

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