Surface features and thermal stability of mesoporous Fe doped geoinspired synthetic chrysotile nanotubes

Synthetic mesoporous Fe doped geoinspired nanotubes have been utilized to evaluate the modification of the surface composition, morphology charge distribution and thermal stability as functions of the Fe doping extent and Fe prevalent substitution into the octahedral or tetrahedral sites. FTIR-ATR spectroscopy analysis has allowed to highlight the chrysotile structure modification by the Fe substitution to Mg or Si and to underline clearly the crucial role of the Fe doping in the octahedral sheet in modifying chrysotile structure and morphology. XPS analysis, zeta-potentials and porosity characterization have allowed to define the propriety of the chrysotile surface structure when iron replaces Mg in octahedral or Si in tetrahedral sites. DTA analysis has allowed to relate the effect of Fe doping on the chemical-physical characteristics of both synthetic and mineral chrysotile. We have observed that the simultaneous decrease in dehydroxylation and recrystallization temperature occurs when the Fe increases on surface and this is due to the increased substitution of Fe in octahedron. The results highlight the relevance to estimate the health hazard of the natural asbestos fibres by valuating the role of Fe surface throughout the use of geoinspired chrysotile synthesised under controlled stoichiometry and structure utilizing it as a selected reference standard. (C) 2014 Elsevier Inc. All rights reserved.