Mössbauer effect study of the effect of gamma irradiation and heat treatment on montmorillonite

Eissa, N. A.; Sheta, N. H.; Meligy, W. M. El; Sallam, H. A.

doi:10.1007/bf02064607

Cited by 6 publications

(4 citation statements)

References 7 publications

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“…It has been previously demonstrated that at those irradiation doses montmorillonite does not suffer an alteration in its lattice [20]. In these experiments, the clay protects the organic molecule from the action of radiation, through a yet unidentified mechanism.…”

Section: Resultsmentioning

confidence: 86%

Heterogeneous radiolysis of urea. Implications in astrobiology and prebiotic chemistry

et al. 2014

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Abstract:Urea is an organic molecule present in most living organisms. Historically, it was the first organic molecule synthesized in the laboratory. In prebiotic chemistry, urea readily forms in different laboratory simulations using different energy sources. Furthermore, the role of solid surfaces, particularly minerals, might have been crucial to increase the complexity of the organic matter which may have led to the subsequent emergence of life on Earth.In this work, the radiolysis of urea in presence of a clay is studied to determine to what extent the mineral surfaces influence the decomposition of organics. The results indicate that urea is relatively stable to ionizing radiation in aqueous solutions and up to 20 kGy no decomposition is observed. Moreover, the presence of sodium montmorillonite, by a mechanism until now unknown, affects the radiolytic behavior and urea remains in the heterogeneous solution without a change in concentration even at very high doses (140 kGy). These results indicate that solids could have protected some organics, like urea, from degradation enabling them to remain in the environment on the primitive Earth.

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Section: Resultsmentioning

confidence: 86%

Heterogeneous radiolysis of urea. Implications in astrobiology and prebiotic chemistry

et al. 2014

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“…A new component that appeared at 900ºC was attributed to a spinel. Finally, Eissa et al (1994), in a study of a montmorillonite that was not further characterized, observed a major increase in quadrupole splitting between 500 and 600ºC, the development of magnetically ordered hematite in room-temperature Mössbauer spectra between 950 and 1100ºC, and the (re)appearance of Fe 2+ and disappearance of hematite at 1200ºC.…”

mentioning

confidence: 93%

The thermal reactions of montmorillonite: a Mössbauer study

Murad

Wagner

et al. 2002

Clay miner.

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A B S T R A C T : The physical properties of three montmorillonites before and after heating were studied by reflectance colorimetry, X-ray diffraction (XRD) and infrared (IR) and Mö ssbauer spectroscopies. Colorimetric data, though not directly relatable to sample mineralogy, provide cheap and rapid information on the temperatures of sample breakdown. X-ray diffraction provides information on sample mineralogy and the transformations that develop during firing and allows the major phases formed in the course of firing to be identified, whereas IR data provide information on water and hydroxyl loss and the final breakdown of the montmorillonite structure. Mö ssbauer spectroscopy gives information on Fe 2+ oxidation (where applicable) and reveals subtle variations in Fe site coordination and Fe mineralogy, including the formation of Fe oxides -that can be quantified in proportions as low as 0.1% -following structural breakdown of the montmorillonites.

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“…Particularly, the light brown of raw M changed to orange and green color for M-210-24 and Mac1-210-24 samples, respectively. These color differences could be attributed to changes in the structural iron oxidation state (Eissa et al, 1994). The M-HC compounds showed dark brown (MC10ac1-180-16 sample) or black color (MD25-180-16 and MAMac1-210-24, samples) which revealed the M surface coating by carbonaceous materials (Zhang et al, 2015).…”

Section: Characterization Of the Hydrothermal Carbonsmentioning

confidence: 98%

Montmorillonite- hydrothermal carbon nanocomposites: Synthesis, characterization and evaluation of pesticides retention for potential treatment of agricultural wastewater

Soulé

Fernández

Montes

et al. 2020

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Mössbauer effect study of the effect of gamma irradiation and heat treatment on montmorillonite

Cited by 6 publications

References 7 publications

Heterogeneous radiolysis of urea. Implications in astrobiology and prebiotic chemistry

Heterogeneous radiolysis of urea. Implications in astrobiology and prebiotic chemistry

The thermal reactions of montmorillonite: a Mössbauer study

Montmorillonite- hydrothermal carbon nanocomposites: Synthesis, characterization and evaluation of pesticides retention for potential treatment of agricultural wastewater

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