title: Bioaccessibility of micron-sized powder particles of molybdenum metal, iron metal, molybdenum oxides and ferromolybdenum--Importance of surface oxides.
abstract: The European chemical framework REACH requires that hazards and risks posed by chemicals, including alloys and metals, that are manufactured, imported or used in different products (substances or articles) are identified and proven safe for humans and the environment. Metals and alloys need hence to be investigated on their extent of released metals (bioaccessibility) in biologically relevant environments. Read-across from available studies may be used for similar materials. This study investigates the release of molybdenum and iron from powder particles of molybdenum metal (Mo), a ferromolybdenum alloy (FeMo), an iron metal powder (Fe), MoO2, and MoO3 in different synthetic body fluids of pH ranging from 1.5 to 7.4 and of different composition. Spectroscopic tools and cyclic voltammetry have been employed to characterize surface oxides, microscopy, light scattering and nitrogen absorption for particle characterization, and atomic absorption spectroscopy to quantify released amounts of metals. The release of molybdenum from the Mo powder generally increased with pH and was influenced by the fluid composition. The mixed iron and molybdenum surface oxide of the FeMo powder acted as a barrier both at acidic and weakly alkaline conditions. These findings underline the importance of the surface oxide characteristics for the bioaccessibility of metal alloys.
authors.affiliation: KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, SE-10044 Stockholm, Sweden.
authors.forename: Alexander
authors.initials: A
authors.lastname: Mörsdorf
authors.affiliation: KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, SE-10044 Stockholm, Sweden.
authors.forename: Inger
authors.initials: I
authors.lastname: Odnevall Wallinder
authors.affiliation: KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, SE-10044 Stockholm, Sweden. Electronic address: yolanda@kth.se.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Hedberg
mesh_terms: D000497:Alloys / Q000737:chemistry*; D001682:Biological Availability; D001826:Body Fluids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D008982:Molybdenum / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010316:Particle Size; D011208:Powders
chemical_list: D000497:Alloys; D010087:Oxides; D011208:Powders; C539565:molybdenum dioxide; C082290:molybdenum trioxide; D008982:Molybdenum; D007501:Iron
keywords: Alloy; Bioaccessibility; Ferromolybdenum; Molybdenum; Surface oxide