Chrysotile Structure Research Articles

INFLUENCE OF STRUCTURAL FEATURES OF CHRYSOTYLE CRYSTALS ON THE ACTION OF THE SYSTEM OF CHRYSOTYLE AND SULFURIC ACID

The nature of the interactions between chrysotile and stoichiometrically necessary amounts (SNA) of sulfuric acid calculated in relation to the amount (molar) of magnesium contained in chrysotile – Mg6[Si4O10](OH) has been studied. It has been shown that when using solutions containing sulfuric acid HCl (0-0.3), the amount of magnesium found in the solution corresponds to a proportional amount of the acid used. It was found that the output of magnesium into the solution slows down in the range of SNA (0.3-0.5). Proportionally, the dissolution of magnesium is restored in the range of SNA (0.5-0.7). However, the yield of magnesium in solution does not exceed 76% of its content in chrysotile due to the formation of polysilicon acid (SiO2·nN2O) in an acidic medium. The layer formed on the surface consisting of polysilicon acids is the main factor inhibiting the transition of magnesium into solution.It was revealed that the amount of magnesium passing into solution depends not only on the concentration of acid, but also on the density of the layered structure of chrysotile. The conclusions are based on the results of chemical and X-ray phase studies of reaction products occurring during the dissolution of chrysotile asbestos in solutions of sulfuric acid H2SO4.Based on results of the study, it was shown that the dissolution of magnesium silicates, the composition of which of minerals (chrysotile, lizardite, antigorite) of the serpentinite group with the general formula Mg6[Si4O10](OH)8 in acids depends not only on the patterns of acid-base interactions occurring under these conditions, but also on the structural features of the serpentinite crystal lattice.

Thermoacid Behavior of Serpentinite of the Zhitikarinsky Deposit (Kazakhstan).

Thermoacid behavior of serpentinite from the Zhitikarinsky field (g. Zhitikara, Kazakhstan). The character of dissolution of heat-treated serpentinite in a narrow temperature range of 600-750 °C is investigated, where the crystal lattice of the structural structure of chrysotile in sulfuric acid is destroyed. The X-ray and chemical analysis of the products of dissolution of heat-treated serpentinite at 600 °C, 725 °C and 750 °C in sulfuric acid solution show that the reason for the increase in the reactivity of heat-treated serpentinite at 725 °C and 750 °C with respect to the acidic medium and the degree of magnesium extraction into sulfate solution is the formation of periclase (MgO) in the serpentinite composition after heat treatment of them within a temperature range of 600-750 °C. The results were discussed using data obtained by conducting a thermodynamic evaluation of probable reactions during the thermoacid treatment of serpentinite, phase compressions of heat-treated serpentinite at 600-750 °C, and after its acid treatment at 1.0 M H2SO4.

Transformation of Silicate Ions into Silica under the Influence of Acid on the Structure of Serpentinite.

The process of transformation of the silicate components of the crystal lattice structure of chrysotile during its quantitative interaction with aqueous solutions containing various stoichiometrically required amounts of sulfuric acid (SRA H2SO4) calculated with respect to the magnesium content in the composition of chrysotile is investigated. It has been shown by IR spectroscopic, X-ray phase, thermal and chemical methods of investigation and analysis that, with quantitative interactions of chrysotile and sulfuric acid, first of all, the "brucite layer" of the molecular structural structure of chrysotile is exposed to acid at SRA H2SO4 = 0.1-0.3. As a result of ion exchange processes, acidic silanol (≡Si-O-H) or disilanol (=Si=(O-H)2) bonds are formed. These acid groups form one-dimensional silicate chains with transverse bridges (≡Si-O-Si≡), where the angles (Si-O-Si = 180 °C) straighten, which are recorded in the IR spectra in the region of characteristic absorption of 1220-1250 cm-1 silica. The association of the resulting acid groups into silicate chains, dimers, and trimers with transverse bridges, leads to the appearance of colloidal silica particles in the system, which cause some inhibition of the dissolution of layered magnesium hydrosilicate in sulfuric acid solutions containing H2SO4 ˃ 0.3 SRA.

Application of Organosilicon Modifier Based on Tetraethoxysilane for the Production of Heat-Resistant Chrysotile Fibers and Reinforced Cement Composites

This research is aimed at obtaining boron-containing nanotubular chrysotile fibers with increased neutron absorption capacity. The possibility of using an organosilicon modifier based on tetraethoxysilane to increase the hydrothermal stability of chrysotile, as well as the strength of nanoreinforced composites based on a cement binder is considered. The mechanisms for the synthesis of heat-resistant nanotubular fibers of the composition Mg6(OH)8SiB4O10, which have a chrysotile structure, have been established. To increase the hydrothermal stability of chrysotile, crystalline hydrate phases were localized inside nanotubes using amorphous silica formed as a result of hydrolysis of silicon alkoxide under hydrothermal conditions in an alkaline environment. The modification of chrysotile via amorphous silica increases its hydrothermal stability by 97 °C. It is shown that the introduction of an organosilicon modifier based on tetraethoxysilane into the composition of Portland cement composite material leads to an increase in the structural strength and density of the composite due to the activation of silicate formation processes in the cement matrix, especially under hydrothermal conditions. The experiments showed that the strength of silicon alkoxide-modified samples of composite material increased by 34%.

Mechanical and magnetic properties of Mg-Ni hydrosilicate nanoscrolls as study objects for atomic force microscopy

In hydrosilicates with the structure of chrysotile, pecoraite, and halloysite, elastic strains in the composite hydrosilicate layer are compensated by folding into nanoscrolls. A wide range of such particles with different compositions can be produced by hydrothermal synthesis, which, together with the structural and morphological characteristics, makes them promising adsorbents, capsules, catalysts, and reinforcing components of composite materials. For such potential applications as magnetically controlled adsorbents and catalysts, ferromagnetic chemical elements are included in the composition of the nanoscrolls. Studies of the individual nanoscrolls require special approaches. This article discusses the use of atomic force microscopy for such studies.

Polygonal Serpentine and Chrysotile in the Kurosegawa Belt, Kyushu, Japan

AbstractThe basic crystallographic properties of polygonal serpentine (PS) have been revealed in previous studies, while their variation, occurrence, and formation conditions are poorly understood. This study defines four categories of chrysotile and PS: clinochrysotile (chrysotile 2Mc1), orthochrysotile (chrysotile 2Orc1), clino-type PS, and ortho-type PS. When chrysotile and PS coexist or are indistinguishable, we will call them fibrous serpentine (FS), regardless of their ratios. By researching the occurrence, distribution, microtexture, crystal structure, and chemical composition of PS and chrysotile based on these categories, we reveal the features of each type and discuss their relationships and formation processes. The chrysotile and PS of the Kurosegawa belt in Kyushu are enriched in ortho-type FS (O-FS) compared with other localities. O-FS-enriched samples (group-O) show a linear, wide vein occurrence and splintery texture or irregular veins with space-filling textures, while clino-type FS (C-FS)-enriched samples occur as thin veins in serpentinites or as massive-foliated aggregates. Polygonal serpentine is more frequently seen in group-O compared with group-C. In our observation, the crystal structure of chrysotile and PS is continuous, making it difficult to define a clear border between them. Ortho-type PS is frequently seen, whereas clino-type PS is absent in most localities. Orthochrysotile tends to grow into 15-sectored ortho-type PS, whereas clinochrysotile grows into 30-sectored clino-type PS. These features of the crystal structure and coexistence and proportion of the fibrous serpentines in each group were mostly common in all studied localities in the Kurosegawa belt in Kyushu, indicating similar formation conditions within group-O or -C. Based on the textures and occurrences, group-O formed by crystallization from the fluid in the fracture made by brittle deformation, while group-C formed in the last stage of alteration mainly by replacement by alteration. The serpentines in the Kurosegawa belt in Kyushu seem to have followed a similar process, at least at the late stage of serpentinization where FS forms and the difference in the ratio of C-FS to O-FS may have been derived from the difference in the timing of formation during the emplacement process. A formation model for chrysotile and PS is proposed based on these observations. In this model, C-FS and O-FS form under different conditions, such as differences in pressure. This model still needs verification by further observations at different localities and by synthetic experiments.

Formation of Magnesium Hydrosilicate Nanoscrolls with the Chrysotile Structure from Nanocrystalline Magnesium Hydroxide and Their Thermally Stimulated Transformation

Formation of Magnesium Hydrosilicate Nanoscrolls with the Chrysotile Structure from Nanocrystalline Magnesium Hydroxide and Their Thermally Stimulated Transformation

Biological treatment of asbestos cement wastes by Aspergillus niger and Acidithiobacillus thiooxidans

Asbestos cement materials used in the past by the building construction sector still poses environmental problems, requiring proper treatment and storage. Here we investigated an alternative microbiological-induced treatment of raw chrysotile and asbestos cement materials. Based on the knowledge that some microorganisms , such as Aspergillus niger (fungus) and Acidithiobacillus thiooxidans (bacteria) are potential organic or inorganic acid producers, we evaluated the dissolution of the chrysotile structure, which is the toxic component in these materials, under submerged and solid-state cultivation conditions. The Mg, and Ca release percentage evaluated and SEM/EDX, XRD, and FTIR characterization data have shown a high potential of both microorganisms studied to total chrysotile degradation (up to 100%, based on Mg content), using either the microbial filtrate, submerged and solid-state cultivation. The present study is a potential biological treatment of asbestos cement materials that can also be applied in situ in areas contaminated with asbestos, which is an alternative not applied to energy-intensive methods such as mechanochemical or thermal treatment. • Asbestos cement wastes bioremediation; • Biological routes to detoxify asbestos cement wastes; • Mg 2+ and Ca 2+ bioleaching ; • Chrysotile biological mineralization; • Environmentally-friendly strategy to detoxify asbestos cement wastes.

Effect of Grinding on Chrysotile, Amosite and Crocidolite and Implications for Thermal Treatment

Nowadays, due to the adverse health effects associated with exposure to asbestos, its inertization is one of the most important issues of waste risk management. Based on the research line of mechano-chemical and thermal treatment of asbestos containing materials, the aim of this study was to examine the effects of dry grinding on the structure, temperature stability and fibre size of chrysotile from Balangero (Italy), as well as standard UICC (Union for International Cancer Control) amosite and standard UICC (Union for International Cancer Control) crocidolite. Dry grinding was accomplished in an eccentric vibration mill by varying the grinding time (30 s, 5 and 10 min). Results show a decrease in crystallinity, the formation of lattice defects and size reduction with progressive formation of agglomerates in the samples after the mechanical treatment. Transmission electron microscopy (TEM) results show that the final product obtained after 10 min of grinding is composed of non-crystalline particles and a minor residue of crystalline fibres that are not regulated because they do not meet the size criteria for a regulated fibre. Grinding results in a decrease of temperature and enthalpy of dehydroxylation (ΔHdehy) of chrysotile, amosite and crocidolite. This permits us to completely destroy these fibres in thermal inertization processes using a lower net thermal energy than that used for the raw samples.

Influence of high-energy milling on structure and microstructure of asbestos-cement materials

Abstract Asbestos-Containing Waste (ACW) in the form of a fragment from an asbestos-cement board was subjected to high-energy milling in a planetary mill at a constant rotational speed of 650 rpm and for variable milling times: 1, 2, and 3 h. The initial and the milled materials were subjected to infrared spectroscopic examination to identify the asbestos variety and to evaluate changes in the structure caused by high-energy milling. FT-IR (Fourier Transform Infrared Spectroscopy) examinations followed optical microscopy and SEM (Scanning Electron Microscopy) studies as well as X-ray analysis of the phase composition. It was found that the asbestos fibres present in the asbestos-cement board were respirable fibres with pathogenic properties. Identifying asbestos using the spectroscopic method showed that chrysotile asbestos was present in the as-received ACW while no characteristics of absorption bands from crocidolite or amosite were found. The results of the spectroscopic examinations were confirmed by the X-ray phase analysis. During SEM investigations of the milled ACW, complete loss of the fibrous structure of chrysotile was observed. The FT-IR examinations of the milled material showed that with an increased milling time, the characteristic absorption bands characteristic for chrysotile diminished and already after 2 h of milling their almost complete decay was observed. Thereby, it was confirmed that high-energy milling results in destruction of the crystalline structure of the asbestos phase. The conducted studies have shown that the treatment of asbestos-cement materials using high-energy milling is an effective method for asbestos disposal, capable of competing with other technologies and solutions. Moreover, FT-IR spectroscopy was found to be useful to identify asbestos phases and to assess changes caused by high-energy milling.

Redistribution of Mg and Ni cations in crystal lattice of conical nanotube with chrysotile structure

Redistribution of Mg and Ni cations in crystal lattice of conical nanotube with chrysotile structure

Dissolution-reprecipitation and self-assembly of serpentine nanoparticles preceding chrysotile formation: Insights into the structure of proto-serpentine

Any poorly crystalline serpentine-type mineral with a lack of recognizable textural or diffraction features for typical serpentine varieties (i.e., chryotile, lizardite, and antigorite) is usually referred to as proto-serpentine. The formation of the so-called proto-serpentine seems ubiquitous in serpentinization reactions. It is related to dissolution-precipitation of strongly reactive particles prior to true serpentine formation (e.g., in veins where both chrysotile and proto-serpentine are described). However, the structural characteristics of proto-serpentine and its relation with serpentine crystalline varieties remain unclear. In this study a model describing the transformation from proto-serpentine to chrysotile is presented based on experimental chrysotile synthesis using thermogravimetric analyses, transmission electron microscopy, and high-energy X-ray diffraction with pair distribution function analyses. The combination of the high-resolution TEM and high-energy X-ray diffraction enables to resolve the local order of neo-formed particles and their structuration processes occurring during pure chrysotile formation (i.e., during the first three hours of reaction). The formation of individual nanotubes is preceded by the formation of small nanocrystals that already show a chrysotile short-range order, forming porous anastomosing features of hydrophilic crystallites mixed with brucite. This is followed by a hierarchical aggregation of particles into a fiber-like structure. These flake-like particles subsequently stack forming concentric layers with the chrysotile structure. Finally, the individualization of chrysotile nanotubes with a homogeneous distribution of diameter and lengths (several hundreds of nanometer in length) is observed. The competitive precipitation of brucite and transient serpentine during incipient serpentinization reaction indicates that both dissolution-precipitation and serpentine-particle aggregation processes operate to form individual chrysotile. This study sheds light into mineralization processes and sets a first milestone toward the identification of the factors controlling polymorph selection mechanisms in this fascinating system.

Dissolution of the chrysotile structure in nitric-acid solutions at different pH

AbstractThe nitric-acid dissolution of chrysotile was investigated with the aim of revealing the effect of pH on its structure. Chrysotile becomes more soluble at lower pH, with the octahedral, brucite sheet more readily dissolved than the tetrahedral sheet. The dissolution of the brucite sheet increases the pH of the solvent, because of the release of OH− groups along with the Mg2+ ions. At pH 2.00, the characteristic cylindrical fibre bundle structure of chrysotile is retained after dissolution, although the outside surface of each fibre becomes rough. Chrysotile remains fibrous upon dissolution at pH 1.08, but the fibres are no longer crystalline and their cylindrical structure collapses. The nitric-acid treatments result in an increase in both the specific surface area and the pore volume of chrysotile.

Effect of temperature on the synthesis of nanoparticles with different morphology in the system MgO–SiO2–TiO2–H2O under hydrothermal conditions

Nanoparticles with different morphology have been obtained by hydrothermal method in the system MgO–SiO2–TiO2–H2O. It has been found that in the investigated temperature–time interval the formation of nanotubes of hydrosilicate with the structure of chrysotile with a small amount of impurity phases predominantly takes place.

Relaxation processes in an aromatic polyamide-imide and composites on its basis with hydrosilicate nanoparticles

Features of the relaxation behavior of an aromatic polyamide-imide and a composite with nanotubes of magnesium silicate with the structure of chrysotile have been studied by dynamic mechanical analysis, dielectric spectroscopy, and differential scanning calorimetry. Two secondary relaxation (β1 and β2) transitions have been found, the activation energies of these processes have been determined, and the solvent effect on the cooperativeness degree has been studied. Changes in the value of the apparent activation energy of the β1-process caused by the subsequent heating of polymeric and composite samples have been analyzed according to the Starkweather procedure. It has been shown that, as the solvent is released from the polyamide-imide film, the polymer exhibits increasing local mobility, which are predetermined by the structure of the molecular unit. Using the GAMESS software, we have assumed the most probable dimer conformations that correspond to two repeating units of the polyamide-imide molecule.

Нанотрубчатые хризотиловые наполнители для радиационно-защитных конструкционных композитов

ExtEndEd AbstrAct: Strengthening of manifestation of quantum-dimensional effect in nanoparticles will make considerable impact on absorption of photon radiation. Therefore, application of ultradisperse systems will promote high-quality strengthening of radiation protective properties of material and will allow creation of more compact material with improved protective characteristics. The unique combination of properties of chrysotile allows creation of the materials on its basis which possess high mechanical and thermal strength, radiation resistance. The presence of the combined water in its structure favours appearance of radiation protective properties by neutron radiation in such materials. In this connection the authors offered to fill chrysotile nanotubes with nanodispersed compounds that make it possible to raise its radiation protective characteristics. As a result, these compounds have to possess higher extinction coefficient of γ-radiation, and respectively possess high density and content of heavy elements. Nanocrystal plumbous tungstate of PbWO 4 is offered to use as compound for intercalation. The authors developed a method to produce nanotubular filler of radiation protective composite materials by filling hydrosilicate nanotubes of chrysotile structure with refractory slightly soluble compound on the basis of PbWO4 and serial processing of material with solutions of reagents. The best result has been achieved when chrysotile was treated consistently in K 2 WO 4 and Pb(СН 3 СОО) 2 solutions, at the same time mass content of PbWO 4 in an end product reaches 30%. The introduced K 2 WO 4 filled nanotubes not only in the internal channel, but also

열처리에 따른 백석면의 광물학적 특성 변화와 열분해 과정 연구

백석면[Chrysotile, <TEX>$Mg_3Si_2O_5(OH)_4$</TEX>]은 사문석군 광물에 속하는 1:1 층상규산염광물로 섬유상의 형태와 구조적 특성으로 인해 다양한 이용과 연구가 진행되었으나, 근래에는 1급 발암물질로 선정되면서 백석면의 분해에 따른 본질적인 무해화를 위한 연구의 관심도가 높아졌다. 따라서 이 연구는 열처리에 따른 백석면의 광물학적 특성 변화를 관찰하여 열분해에 따른 무해화 과정을 알아보고자 하였다. 실험은 캐나다 LAB Chrysotile 광상에서 산출되는 백석면을 이용하여 <TEX>$600-1,300^{\circ}C$</TEX> 범위에서 2시간 동안 열처리를 하였으며, TG-DTA, XRD, FT-IR, SEM-EDS, TEM-EDS 분석을 통해 백석면의 결정구조, 형태 및 화학성분의 변화를 확인하여 광물학적 특성변화를 관찰하였다. 열분해 실험 결과, 섬유상의 hollow tube 구조를 가지는 백석면은 약 <TEX>$600-650^{\circ}C$</TEX>에서 흡열반응이 일어남에 따라 팔면체판(MgOH)에서 수산기(OH)가 제거되면서 백석면은 비정질 광물의 형태로 변화하였다(탈수화 1단계). 약 <TEX>$820^{\circ}C$</TEX>에서는 발열반응이 관찰되었으며 이는 Mg, Si, O의 재배열 결과 주상의 고토감람석(forsterite, <TEX>$Mg_2SiO_4$</TEX>)으로 상전이에 영향을 준 것으로 사료된다(탈수화 2단계). 또한 <TEX>$800^{\circ}C$</TEX> 이상으로 열처리한 일부 시료에서 고토감람석 내 결정구조의 변화가 시작되었고, <TEX>$1,000^{\circ}C$</TEX> 이상에서는 온도 상승에 따라 점진적인 재결정 작용 결과 3차원적으로 성장하여 구형광물로 형태 변화가 나타나며 완화휘석(enstatite, <TEX>$MgSiO_3$</TEX>)을 형성하였다. 따라서 이 연구는 다양한 분석법의 적용과 2시간 동안의 열처리를 통하여 백석면의 탈수화 반응에 따른 결정구조의 붕괴와 섬유상 형태의 변형을 확인하였으며, 백석면은 무해 광물인 고토감람석과 완화휘석으로 상전이 됨을 통해 백석면의 무해화 과정을 제시 할 수 있었다. Chrysotile is a 1:1 sheet silicate mineral belonging to serpentine group. It has been highlighted studies because of uses, shapes and structural characteristics of the fibrous chrysotile. However, it was designated as Class 1 carcinogen, so high attentions were being placed on detoxification studies of chrysotile. The objectives of this study were to investigate changes of mineralogical characteristics of chrysotile and to suggest detoxification mechanism of chrysotile by thermal decomposition. Samples for this study were obtained from LAB Chrysotile mine in Canada. The samples were heated in air in the range of 600 to <TEX>$1,300^{\circ}C$</TEX>. Changes of mineralogical characteristics such as crystal structure, shape, and chemical composition of the chrysotile fibers were examined by TG-DTA, XRD, FT-IR, TEM-EDS and SEM-EDS analyses. As a result of thermal decomposition, the fibrous chrysotile having hollow tube structure was dehydroxylated at <TEX>$600-650^{\circ}C$</TEX> and transformed to disordered chrysotile by removal of OH at the octahedral sheet (MgOH) (Dehydroxylation 1). Upon increasing temperature, it was transformed to forsterite (<TEX>$Mg_2SiO_4$</TEX>) at <TEX>$820^{\circ}C$</TEX> by rearrangement of Mg, Si and O (Dehydroxylation 2). In addition, crystal structure of forsterite had begun to transform at <TEX>$800^{\circ}C$</TEX>, and gradually grown 3-dimensionally to enstatite (<TEX>$MgSiO_3$</TEX>) by recrystallization after the heating above <TEX>$1,100^{\circ}C$</TEX>. And then finally transformed to spherical minerals. This study showed chrysotile structure was collapsed about <TEX>$600-700^{\circ}C$</TEX> by dehydroxylation. And then the fibrous chrysotile was transformed to forsterite and enstatite, as non-hazardous minerals. Therefore, this study indicates heat treatment can be used to detoxification of chrysotile.

Energy model of bilayer nanoplate scrolling: Formation of chrysotile nanoscroll

Energy model of formation of multiwall nanoscrolls from thin layers has been proposed. The three major factors favoring the scrolling are dimensional mismatch of the crystal lattices forming the bilayer, difference of the surface energy at the bilayer sides, and the interaction between the bilayers. Optimal cross-section geometry of the finite-length nanoscrolls with chrysotile structure has been simulated. Effects of the Young’s modulus, specific surface energy, and adhesion energy on the nanoscroll morphology have been considered.

Adsorption of bovine serum albumin onto synthetic Fe-doped geomimetic chrysotile.

Synthetic stoichiometric and Fe-doped geomimetic chrysotile nanocrystals represent a reference standard to investigate the health hazard associated with mineral asbestos fibres. Experimental evidence suggests that the generation of reactive oxygen species and other radicals, catalysed by iron ions at the fibre surface, plays an important role in asbestos-induced cytotoxicity and genotoxicity. In this study, structural modification of bovine serum albumin (BSA) adsorbed onto synthetic chrysotile doped with different amounts of Fe has been investigated by Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA) and analytical pyrolysis coupled with gas chromatography-mass spectrometry. FT-IR data evidenced a marked increase in disordered structures like random coil and β-turn of BSA-nanocrystal adduct with 0.52 wt% of Fe doped. The TGA profile of the BSA revealed that its interaction with the synthetic chrysotile surface was strongly affected by the substitution of Fe into the chrysotile structure. The 2,5-diketopiperazine yields, formed upon thermal degradation of the polypeptide chain (pyrolysis-gas chromatography), changed when the BSA was adsorbed on the nanofibres. In general, results suggested that minute amount (less than 1 wt%) of Fe doping in chrysotile affected the protein-nanofibre interactions, supporting the role that this element may play in asbestos toxicity. The catalytic role of iron and the consequent unfolding of protein due to the structural surface modification of nanofibres were also evaluated.

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, ζ-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.