title: Release of Si from silicon, a ferrosilicon (FeSi) alloy and a synthetic silicate mineral in simulated biological media.
abstract: Unique quantitative bioaccessibility data has been generated, and the influence of surface/material and test media characteristics on the elemental release process were assessed for silicon containing materials in specific synthetic body fluids at certain time periods at a fixed loading. The metal release test protocol, elaborated by the KTH team, has previously been used for classification, ranking, and screening of different alloys and metals. Time resolved elemental release of Si, Fe and Al from particles, sized less than 50 µm, of two grades of metallurgical silicon (high purity silicon, SiHG, low purity silicon, SiLG), an alloy (ferrosilicon, FeSi) and a mineral (aluminium silicate, AlSi) has been investigated in synthetic body fluids of varying pH, composition and complexation capacity, simple models of for example dermal contact and digestion scenarios. Individual methods for analysis of released Si (as silicic acid, Si(OH)4) in synthetic body fluids using GF-AAS were developed for each fluid including optimisation of solution pH and graphite furnace parameters. The release of Si from the two metallurgical silicon grades was strongly dependent on both pH and media composition with the highest release in pH neutral media. No similar effect was observed for the FeSi alloy or the aluminium silicate mineral. Surface adsorption of phosphate and lactic acid were believed to hinder the release of Si whereas the presence of citric acid enhanced the release as a result of surface complexation. An increased presence of Al and Fe in the material (low purity metalloid, alloy or mineral) resulted in a reduced release of Si in pH neutral media. The release of Si was enhanced for all materials with Al at their outermost surface in acetic media.
authors.affiliation: KTH Royal Institute of Technology, Division of Surface and Corrosion Science, School of Chemical Science and Engineering, Stockholm, Sweden.
authors.forename: Gunilla
authors.initials: G
authors.lastname: Herting
authors.affiliation: KTH Royal Institute of Technology, Division of Surface and Corrosion Science, School of Chemical Science and Engineering, Stockholm, Sweden.
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
authors.affiliation: KTH Royal Institute of Technology, Division of Surface and Corrosion Science, School of Chemical Science and Engineering, Stockholm, Sweden.
authors.forename: Carin
authors.initials: C
authors.lastname: Sjöstedt
authors.affiliation: KTH Royal Institute of Technology, Division of Surface and Corrosion Science, School of Chemical Science and Engineering, Stockholm, Sweden.
authors.forename: Inger
authors.initials: I
authors.lastname: Odnevall Wallinder
mesh_terms: D000497:Alloys / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008903:Minerals / Q000737:chemistry*; D008956:Models, Chemical; D010316:Particle Size; D011522:Protons; D017640:Silicates / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*
chemical_list: D000497:Alloys; D008903:Minerals; D011522:Protons; D017640:Silicates; D017655:Silicon Compounds; C027394:ferrosilicon; D012825:Silicon