Asbestos health hazard: A spectroscopic study of synthetic geoinspired Fe-doped chrysotile

• Published in: Journal of hazardous materials Vol. 167; no. 1; pp. 1070 - 1079
• Main Authors: Foresti, Elisabetta, Fornero, Elisa, Lesci, Isidoro Giorgio, Rinaudo, Caterina, Zuccheri, Tommaso, Roveri, Norberto
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.08.2009; Elsevier
• Subjects: Applied sciences; Asbestos - chemistry; Asbestos - toxicity; Asbestos health hazard; Asbestos, Serpentine - chemistry; Asbestos, Serpentine - toxicity; Catalysis; Catalytic reactions; Chemical engineering; Chemistry; Environmental Health; Exact sciences and technology; Fe-substitution; General and physical chemistry; Hazardous Substances; Inorganic geoinspired nanotubes; IR-Raman spectroscopy; Iron - chemistry; Magnesium; Pollution; Reactors; Silicon; Spectrum Analysis; Synthetic chrysotile; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; IR-Raman spectroscopy; Asbestos health hazard; Inorganic geoinspired nanotubes; Synthetic chrysotile; Fe-substitution; Catalytic reaction; Asbestos; Toxicity; Doping; Free radical; Health and environment; Health hazards; Public health
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2009.01.103

The aim of this paper is to investigate by Infrared and Raman spectroscopic analysis the preferred Si and Mg ions replacement by Fe ions, as a function of Fe doping extent, in geoinspired synthetic chrysotile nanocrystals. Without this knowledge it is impossible to obtain a clear correlation between cytotoxicity and chemical–physical properties of chrysotile fibres with Fe-doped chrysotile structural modifications. Electrostatic interactions between T and O adjacent layers has been described as a substitution by trivalent cations for both tetrahedral silicon and octahedral magnesium, producing an excess of negative charge on the tetrahedral sheet and a positive charge on the octahedral one leading to stronger interlayer bonding. The observed iron substitution effect on chrysotile structure stability must be considered in the valuation of the Fe hazardous effect of asbestos fibres on living systems. The chrysotile fibres toxicity appears correlated to the redox activity of iron present in the chrysotile structure. In fact the generation of reactive oxygen species and other radicals appears catalyzed by iron ions and closely related to Fe ions organization in specific crystallographic sites having a capability to activate free radical generation. The Fe substitution to Mg and/or Si in the chrysotile structure appears important for asbestos health hazard investigation. Infrared and Raman spectroscopic analyses have been utilized to investigate Mg and/or Si ions replacement by Fe ions in chrysotile structure as a function of the Fe doping extent. Geoinspired synthetic chrysotile at different Fe doping extents has been obtained as unique phase by hydrothermal reaction in the presence or not of metallic Fe in the synthetic environment. The results highlight that Fe can replace both Mg and Si, differently modifying the chrysotile structure as a function of the Fe doping extent and the Fe doping process. The contemporary iron substitution into the octahedral and tetrahedral sheets reveals an appreciable increase of the dehydroxylation temperature which occurs at higher temperature than for iron-free sample. The results highlight the role of Fe substitution in the asbestos structure influencing the health hazard of biological systems.