3
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Identifying the reactive sites of hydrogen peroxide decomposition and hydroxyl radical formation on chrysotile asbestos surfaces

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Background

          Fibrous chrysotile has been the most commonly applied asbestos mineral in a range of technical applications. However, it is toxic and carcinogenic upon inhalation. The chemical reactivity of chrysotile fiber surfaces contributes to its adverse health effects by catalyzing the formation of highly reactive hydroxyl radicals (HO ) from H 2O 2. In this Haber-Weiss cycle, Fe on the fiber surface acts as a catalyst: Fe 3+ decomposes H 2O 2 to reductants that reduce surface Fe 3+ to Fe 2+, which is back-oxidized by H 2O 2 (Fenton-oxidation) to yield HO . Chrysotile contains three structural Fe species: ferrous and ferric octahedral Fe and ferric tetrahedral Fe (Fe 3+ tet). Also, external Fe may adsorb or precipitate onto fiber surfaces. The goal of this study was to identify the Fe species on chrysotile surfaces that catalyze H 2O 2 decomposition and HO generation.

          Results

          We demonstrate that at the physiological pH 7.4 Fe 3+ tet on chrysotile surfaces substantially contributes to H 2O 2 decomposition and is the key structural Fe species catalyzing HO generation. After depleting Fe from fiber surfaces, a remnant fiber-related H 2O 2 decomposition mode was identified, which may involve magnetite impurities, remnant Fe or substituted redox-active transition metals other than Fe. Fe (hydr)oxide precipitates on chrysotile surfaces also contributed to H 2O 2 decomposition, but were per mole Fe substantially less efficient than surface Fe 3+ tet. Fe added to chrysotile fibers increased HO generation only when it became incorporated and tetrahedrally coordinated into vacancy sites in the Si layer.

          Conclusions

          Our results suggest that at the physiological pH 7.4, oxidative stress caused by chrysotile fibers largely results from radicals produced in the Haber-Weiss cycle that is catalyzed by Fe 3+ tet. The catalytic role of Fe 3+ tet in radical generation may also apply to other pathogenic silicates in which Fe 3+ tet is substituted, e.g. quartz, amphiboles and zeolites. However, even if these pathogenic minerals do not contain Fe, our results suggest that the mere presence of vacancy sites may pose a risk, as incorporation of external Fe into a tetrahedral coordination environment can lead to HO generation.

          Related collections

          Most cited references55

          • Record: found
          • Abstract: not found
          • Article: not found

          Ferrozine---a new spectrophotometric reagent for iron

            Bookmark
            • Record: found
            • Abstract: not found
            • Article: not found

            Mechanisms in the pathogenesis of asbestosis and silicosis.

              Bookmark
              • Record: found
              • Abstract: not found
              • Article: not found

              Colorimetric Determination of Hydrogen Peroxide

                Bookmark

                Author and article information

                Contributors
                walter.schenkeveld@univie.ac.at
                Journal
                Part Fibre Toxicol
                Part Fibre Toxicol
                Particle and Fibre Toxicology
                BioMed Central (London )
                1743-8977
                20 January 2020
                20 January 2020
                2020
                : 17
                : 3
                Affiliations
                [1 ]ISNI 0000 0001 2286 1424, GRID grid.10420.37, Department of Environmental Geosciences, , University of Vienna, ; Althanstraße 14 (UZA II), 1090 Vienna, Austria
                [2 ]ISNI 0000000120346234, GRID grid.5477.1, Copernicus Institute of Sustainable Development, Faculty of Geosciences, , Utrecht University, ; Princetonlaan 8A, 3584 CB Utrecht, the Netherlands
                [3 ]ISNI 0000 0000 9686 6466, GRID grid.6583.8, Institute of Pharmacology and Toxicology, University of Veterinary Medicine, ; Veterinärplatz 1, 1210 Vienna, Austria
                [4 ]ISNI 0000 0001 2348 4034, GRID grid.5329.d, Institute of Solid State Physics, TU Wien, ; Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
                Article
                333
                10.1186/s12989-019-0333-1
                6971994
                31959185
                304d24a7-937b-428e-82ca-e90e2e219f97
                © The Author(s). 2020

                Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

                History
                : 4 September 2019
                : 23 December 2019
                Funding
                Funded by: Universitat Wien
                Award ID: uni:docs program
                Categories
                Research
                Custom metadata
                © The Author(s) 2020

                Toxicology
                asbestos,chrysotile,haber-weiss,hydroxyl radical,fenton,tetrahedral iron,mössbauer,epr
                Toxicology
                asbestos, chrysotile, haber-weiss, hydroxyl radical, fenton, tetrahedral iron, mössbauer, epr

                Comments

                Comment on this article