Chemical stability and dehydration behavior of a sepiolite/indigo Maya Blue pigment

Giustetto, Roberto; Wahyudi, Olivia; Corazzari, Ingrid; Turci, Francesco

doi:10.1016/j.clay.2011.01.027

Cited by 91 publications

(76 citation statements)

References 63 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The overall recorded weight loss ( 16.5 %) is slightly lower than that of other sepiolites (i.e. 18.5-19.5 %: Frost et al, 2009;Giustetto et al, 2011c), possibly as the result of the ascertained deficiencies in the hygroscopic H2O content.…”

Section: Thermogravimetric Analysis (Insert Figure 6)mentioning

confidence: 73%

See 1 more Smart Citation

Asbestiform sepiolite coated by aliphatic hydrocarbons from Perletoa, Aosta Valley Region (Western Alps, Italy): characterization, genesis and possible hazards

Giustetto

Seenivasan²,

Belluso

2014

Mineral. mag.

Self Cite

View full text Add to dashboard Cite

An atypical asbestiform sepiolite occurrence with exceptionally long fibres wrapped by a sheath of aliphatic hydrocarbons was found in the Gressoney Valley (Italian Western Alps) while monitoring asbestos presence in outcrops of serpentinite rocks. Microscopic and Fourier transform infrared analyses proved that these fibres, apparently up to several cm long, are formed by bundles of thinner fibrils (average length: 150 μm) potentially dispersible in the environment. When observed using transmission electron microscopy these fibrils show a rhomboidal to parallelogram cross section (<1 μm), of which surfaces are covered mostly by an aliphatic hydrocarbon film – an association not reported in the literature. The sepiolite fibrils and their organic coating probably originated in sequential steps from precipitation of Si/Mg rich hydrothermal fluids, resulting from serpentinization of olivine and clinopyroxene and a Fischer-Tropsch-type reaction. The presence of hydrocarbons has serious implications for the sepiolite habit, as the organic wrap interacts with the fibril’s surface reducing the amount of adsorbed water and favouring the fragmentation of thicker units into thinner ones, due to an ‘opening’ process implying separation along z and cleavage on (110). This defibrillation mechanism, coupled with the extraordinary length, further increases the aspect ratio of these fibrils (length/width ≫3) thus amplifying their potential danger for human health when dispersed in air and inhaled.

show abstract

Section: Thermogravimetric Analysis (Insert Figure 6)mentioning

confidence: 73%

“…Loss of the 2 nd half of structural OH2, extending from 320 to 620 °C, is marked by no apparent signal in the derivative weight nor heat flow profiles (contrarily to Martin Vivaldi and Fenoll Hach-Ali, 1970 and Giustetto et al, 2011c) thus certifying the slow progression of such an event.…”

Section: Thermogravimetric Analysis (Insert Figure 6)mentioning

confidence: 97%

Asbestiform sepiolite coated by aliphatic hydrocarbons from Perletoa, Aosta Valley Region (Western Alps, Italy): characterization, genesis and possible hazards

Giustetto

Seenivasan²,

Belluso

2014

Mineral. mag.

Self Cite

View full text Add to dashboard Cite

show abstract

“…That same year Shepard (1962) and Shepard and Gottlieb (1962) suggested that the pigment was a clayeorganic complex, and indeed, five years later, the remaining component was identified as the organic colorant, indigo (Kleber et al, 1967). Since then, research on Maya Blue has focused on several interrelated themes, and at least two authors have provided lengthy summaries of the Maya Blue research from a chemical and molecular perspective (Doménech et al, 2011;Giustetto et al, 2011).…”

Section: Brief History Of Maya Blue Researchmentioning

confidence: 99%

“…Palygorskite is a fibrous mineral that is structured with long parallel channels rather than sheets like most clay minerals, and this characteristic, along with that of sepiolite, appears to be critical for the chemical bonding of the indigo to produce Maya Blue's striking color, its unusual chemical stability, and it persistence through time without fading (Chiari et al, 2008;Doménech et al, 2011;Fois et al, 2003;Giustetto et al, 2011).…”

Section: Brief History Of Maya Blue Researchmentioning

confidence: 99%

The first direct evidence of pre-columbian sources of palygorskite for Maya Blue

Arnold

Bohor

Neff

et al. 2012

Journal of Archaeological Science

View full text Add to dashboard Cite

“…Sepiolite is mainly composed of silice (58-59 wt% as oxide) and magnesium (24-25 wt% as oxide) [15]. Spain is the largest producer of sepiolite and accounted for about 95% of the world's annual production in the last decade [16].…”

mentioning

confidence: 99%

Defluidization and agglomeration of a fluidized bed reactor during Cynara cardunculus L. gasification using sepiolite as a bed material

Serrano

Sánchez-Delgado

Sobrino

et al. 2015

Fuel Processing Technology

View full text Add to dashboard Cite

This work studies the defluidization time and the agglomerates generation in a Bubbling Fluidized Bed (BFB) reactor during Cynara Cardunculus L. gasification using, separately, two different bed materials, silica sand and sepiolite (Mg 8 Si 12 O 30 (OH) 4 (OH 2 ) 4 8H 2 ). The high adsorption capacity and the elemental composition of the sepiolite make it suitable as an alternative bed material in order to reduce agglomeration. Experiments were performed on a stainless steel lab-scale BFB reactor operating with air as gasifying agent at different air excess ratios (u/u mf ). A quartz reactor was alternatively used for the visualization of bed material and biomass during gasification, allowing to observe the agglomerate formation process. Pressure signals were analyzed both in time and frequency domain to determine the defluidization time.Furthermore, the shape and size of the bed material after the experiments were evaluated.Higher defluidization times in the case of sepiolite were measured. Particle sizes were affected by the type of bed material and the air excess and agglomerates of different shapes were formed for sepiolite and silica sand.

show abstract

Chemical stability and dehydration behavior of a sepiolite/indigo Maya Blue pigment

Cited by 91 publications

References 63 publications

Asbestiform sepiolite coated by aliphatic hydrocarbons from Perletoa, Aosta Valley Region (Western Alps, Italy): characterization, genesis and possible hazards

Asbestiform sepiolite coated by aliphatic hydrocarbons from Perletoa, Aosta Valley Region (Western Alps, Italy): characterization, genesis and possible hazards

The first direct evidence of pre-columbian sources of palygorskite for Maya Blue

Defluidization and agglomeration of a fluidized bed reactor during Cynara cardunculus L. gasification using sepiolite as a bed material

Contact Info

Product

Resources

About