scholarly journals Ionizing Radiation, an Instrument in Chemical Evolution Studies: Scope and Perspectives

2012 ◽  
Vol 6 (1) ◽  
pp. 99-101 ◽  
Author(s):  
E Y Aguilar-Ovando ◽  
◽  
A Negron-Mendoza ◽  
M L Ramirez-Vazquez ◽  
R C Acosta-Fernandez ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Chemical Evolution

scholarly journals Stability of Pyruvic Acid Adsorbed Onto Clays and Exposed to Ionizing Radiation: Relevance in Chemical Evolution

2020 ◽  
Vol 7 (2) ◽  
pp. 97-101
Author(s):  
R. C Acosta-Fernández ◽  
A. Heredia-Barbero ◽  
A. Negrón-Mendoza
Keyword(s):  
Ionizing Radiation ◽  
Chemical Evolution ◽  
Pyruvic Acid ◽  
Solid Phase ◽  
Main Reaction ◽  
Exchangeable Cation ◽  
Keto Acid ◽  
Sodium Montmorillonite ◽  
Cation Type ◽  
Insight Into

Chemical evolution studies focus on the synthesis and stability of organic molecules during various transformative physicochemical processes. Gaining insight into the possible mechanisms behind these processes requires the use of various energy sources and catalysts that can produce such transformations. In this work, ionizing radiation (60Co) was used as a source of energy, and two clays with different exchangeable cations-sodium and iron (III)-were combined with pyruvic acid, a key alpha keto acid in metabolism. The samples of pyruvic acid were prepared at a concentration of 0.01 M; then, adsorption experiments were carried out by combining sodium or iron montmorillonite at different times. The amount that adsorbed onto iron montmorillonite was greater than the amount that adsorbed onto sodium montmorillonite. Samples of alpha keto acid at the same concentration were irradiated-in the absence of clay-at 0 to 146.1 kGy and at two pHs (6.7 and 2.0). The suspended samples with sodium and iron clay were then irradiated at the same doses. The results show that keto acid decomposes more quickly at more acidic pHs. The main reaction to irradiation without clay involves the dimerization of pyruvic acid, and 2,3-dimethyltartaric acid is the majority product. When irradiated in the presence of clay, the main reaction is decarboxylation, and acetic acid is the majority product. The exchangeable cation type modifies the interactions between the organic molecule and the solid phase. The percentage of recovered pyruvic acid is higher for iron montmorillonite than for sodium montmorillonite.

Radiation-induced surface decomposition

1983 ◽  
Vol 41 ◽  
pp. 368-369
Author(s):  
M. L. Knotek
Keyword(s):  
Ionizing Radiation ◽  
Atomic Structure ◽  
Chemical Bonding ◽  
Neutral Species ◽  
Radiation Induced ◽  
Physical And Chemical ◽  
Surface Decomposition ◽  
The Relationship ◽  
Electron And Photon ◽  
Surface Bond

Modern surface analysis is based largely upon the use of ionizing radiation to probe the electronic and atomic structure of the surfaces physical and chemical makeup. In many of these studies the ionizing radiation used as the primary probe is found to induce changes in the structure and makeup of the surface, especially when electrons are employed. A number of techniques employ the phenomenon of radiation induced desorption as a means of probing the nature of the surface bond. These include Electron- and Photon-Stimulated Desorption (ESD and PSD) which measure desorbed ionic and neutral species as they leave the surface after the surface has been excited by some incident ionizing particle. There has recently been a great deal of activity in determining the relationship between the nature of chemical bonding and its susceptibility to radiation damage.

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