Synthesis of goethite in solutions of artificial seawater and amino acids: a prebiotic chemistry study

2013 ◽  
Vol 12 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Cristine E. A. Carneiro ◽  
Flávio F. Ivashita ◽  
Ivan Granemann de Souza ◽  
Cláudio M. D. de Souza ◽  
Andrea Paesano ◽  
...  
Keyword(s):  
Amino Acids ◽  
Mössbauer Spectra ◽  
Surface Enhanced Raman Spectroscopy ◽  
Artificial Seawater ◽  
The Other ◽  
Isomorphic Substitution ◽  
Distilled Water ◽  
Sem Images ◽  
Mossbauer Spectra ◽  
Prebiotic Earth

AbstractThis study investigated the synthesis of goethite under conditions resembling those of the prebiotic Earth. The artificial seawater used contains all the major elements as well as amino acids (α-Ala, β-Ala, Gly, Cys, AIB) that could be found on the prebiotic Earth. The spectroscopic methods (FT-IR, EPR, Raman), scanning electron microscopy (SEM) and X-ray diffraction showed that in any condition Gly and Cys favoured the formation of goethite, artificial seawater plus β-Ala and distilled water plus AIB favoured the formation of hematite and for the other synthesis a mixture of goethite and hematite were obtained. Thus in general no protein amino acids (β-Ala, AIB) favoured the formation of hematite. As shown by surface enhanced Raman spectroscopy (SERS) spectra the interaction between Cys and Fe3+ of goethite is very complex, involving decomposition of Cys producing sulphur, as well as interaction of carboxylic group with Fe3+. SERS spectra also showed that amino/CN and C-CH3 groups of α-Ala are interacting with Fe3+ of goethite. For the other samples the shifting of several bands was observed. However, it was not possible to say which amino acid groups are interacting with Fe3+. The pH at point of zero charge of goethites increased with artificial seawater and decreased with amino acids. SEM images showed when only goethite was synthesized the images of the samples were acicular and when only hematite was synthesized the images of the samples were spherical. SEM images for the synthesis of goethite with Cys were spherical crystal aggregates with radiating acicular crystals. The highest resonance line intensities were obtained for the samples where only hematite was obtained. Electron paramagnetic resonance (EPR) and Mössbauer spectra showed for the synthesis of goethite with artificial seawater an isomorphic substitution of iron by seawater cations. Mössbauer spectra also showed that for the synthesis goethite in distilled water plus Gly only goethite was synthesized and in artificial seawater plus Cys a doublet due to interaction of iron with artificial seawater/Cys was observed. It should be pointed out that EPR spectroscopy did not show the interaction of iron with artificial seawater/Cys.

Interaction of forsterite-91 with distilled water and artificial seawater: a prebiotic chemistry experiment

2013 ◽  
Vol 12 (2) ◽  
pp. 135-143 ◽  
Author(s):  
Cláudio M. D. de Souza ◽  
Cristine E. A. Carneiro ◽  
João Paulo T. Baú ◽  
Antonio C. S. da Costa ◽  
Flávio F. Ivashita ◽  
...  
Keyword(s):  
Epr Spectroscopy ◽  
Hydrothermal Vents ◽  
Artificial Seawater ◽  
Distilled Water ◽  
Etch Pits ◽  
Sem Images ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Low Concentrations ◽  
Almost All

AbstractIn the present work, the interactions between forsterite-91 with distilled water and forsterite-91 with artificial seawater were studied at two pHs (2.0 and 8.0) using different techniques. A large increase in pH was observed for samples incubated at an initially acidic pH (2.0) due to the dissolution of forsterite-91 in distilled water and artificial seawater. Thus, in acidic hydrothermal vents, an increase in the amount of hydrocarbons and magnetite should be expected due to the release of Fe(II). The pHPZC decreased and the pHIEP increased when forsterite-91 was treated with distilled water and artificial seawater. The ions from the artificial seawater had an effect on zeta potential. Scanning electron microscopy (SEM) images and X-ray diffractograms showed halite in the samples of forsterite-91 mixed with artificial seawater. The presence of halite or adsorption of ions on the surface of forsterite-91 could affect the synthesis of magnetite and hydrocarbons in hydrothermal vents, due to a decrease in the dissolution rates of forsterite-91. The dissolution of forsterite-91 yields low concentrations of Fe(III) and Mn(II) as detected by electron paramagnetic resonance (EPR) spectroscopy. Microanalysis of forsterite-91 showed a higher amount of Mn, with an oxidation that was likely not +II, as Mn in supernatant solutions was only detected by EPR spectroscopy after mixing with artificial seawater at pH 2.0. As Fe(III) and Mn(II) are catalyst constituents of magnetite and manganese oxide, respectively, their presence is important for synthesis in hydrothermal vents. Etch pits were observed only in the forsterite-91 sample mixed with distilled water at pH 8.0. Na, Cl, S, Ca and K were detected in the samples mixed with artificial seawater by SEM–EDS. Si, Mg, Fe and Al were detected in almost all supernatant samples due to forsterite-91 dissolution. Cr was not dissolved in the experiments, thus Cr in the mineral could serve as an effective catalyst for Fischer Tropsch Types (FTT) reactions in hydrothermal vent systems. X-ray diffractograms of the original forsterite-91 also showed peaks arising from zeolites and clinochlore. After the samples were treated with artificial seawater, X-ray diffractograms showed the dissolution of zeolite. Experiments should be performed in the natural environment to verify the potential for zeolites to act as a catalyst in hydrothermal vents.

The influence of aluminium substitution and crystallinity on the Mössbauer spectra of goethite

Clay Minerals ◽  
1983 ◽  
Vol 18 (3) ◽  
pp. 301-312 ◽  
Author(s):  
E. Murad ◽  
U. Schwertmann
Keyword(s):  
Hyperfine Field ◽  
Mössbauer Spectra ◽  
Magnetic Hyperfine Field ◽  
The Other ◽  
Magnetic Hyperfine ◽  
Multiple Correlation ◽  
Independent Variables ◽  
Mossbauer Spectra ◽  
Al Substitution ◽  
Aluminium Substitution

AbstractBoth aluminium substitution and poor crystallinity reduce the magnetic hyperfine field of goethite. Mössbauer spectra taken at 4·2 K show that the effect of poor crystallinity is similar to that of Al substitution, i.e. it reduces the saturation hyperfine field. A multiple correlation was found to exist between the magnetic hyperfine field at 4·2 K as a dependent variable vs Al substitution and crystallinity as independent variables. If a hyperfine field is to be interpreted with respect to either Al substitution or crystallinity, it is therefore necessary to have knowledge of the other variable.

Influence of Structure on the Magnetism of Fe1-xAlx Alloys

2008 ◽  
Vol 1128 ◽  
Author(s):  
Estibaliz Apiñaniz ◽  
Damian Martín-Rodriguez ◽  
Estibaliz Legarra ◽  
J. Javier Saiz Garitaonandia ◽  
Fernando Plazaola
Keyword(s):  
Mössbauer Spectra ◽  
Magnetic Behavior ◽  
Lattice Parameter ◽  
The Other ◽  
X Rays ◽  
Mossbauer Spectra ◽  
Other Hand ◽  
Nearest Neighborhood ◽  
The Relationship

AbstractWith the aim of studying the relationship between structure and magnetism of Fe1-xAlx alloys, annealed and as-crushed samples with 0.25x0.425 been studied. X-rays and Mössbauer spectra show that the nearest neighborhood of each Fe atom plays a major role when determining the magnetic behavior of each Fe atom. In fact, these techniques allow us to determine in which surroundings these Fe atoms will behave paramagnetically. On the other hand, the influence of the lattice parameter has also been studied.

A MODEL FOR EXPLAINING THE MÖSSBAUER SPECTRA OF FERRIMAGNETIC SPINELS WITH A HIGH DEGREE OF DIAMAGNETIC SUBSTITUTION

1979 ◽  
Vol 40 (C2) ◽  
pp. C2-669-C2-670 ◽  
Author(s):  
E. De Grave ◽  
A. Govaert ◽  
D. Chambaere ◽  
G. Robbrecht
Keyword(s):  
Mössbauer Spectra ◽  
Mossbauer Spectra ◽  
High Degree

Laser Modification of Mossbauer Spectra in Eu2+:CaS

2001 ◽  
Author(s):  
Olga Kocharovskaya ◽  
Zameer Hasan ◽  
James Carroll
Keyword(s):  
Mössbauer Spectra ◽  
Laser Modification ◽  
Mossbauer Spectra

scholarly journals Imaging and SERS Study of the Au Nanoparticles Interaction with HPV and Carcinogenic Cervical Tissues

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3758
Author(s):  
Andrea Ceja-Fdez ◽  
Ramon Carriles ◽  
Ana Lilia González-Yebra ◽  
Juan Vivero-Escoto ◽  
Elder de la Rosa ◽  
...  
Keyword(s):  
Multiphoton Microscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Rapid Screening ◽  
Emission Region ◽  
Sem Images ◽  
Spectral Signatures ◽  
Two Photon ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Gold Nps

In this work, gold NPs were prepared by the Turkevich method, and their interaction with HPV and cancerous cervical tissues were studied by scanning electron microscopy, energy-dispersive x-ray spectroscopy, confocal and multiphoton microscopy and SERS. The SEM images confirmed the presence and localization of the gold NPs inside of the two kinds of tissues. The light absorption of the gold NPs was at 520 nm. However, it was possible to obtain two-photon imaging (red emission region) of the gold NPs inside of the tissue, exciting the samples at 900 nm, observing the morphology of the tissues. The infrared absorption was probably due to the aggregation of gold NPs inside the tissues. Therefore, through the interaction of gold nanoparticles with the HPV and cancerous cervical tissues, a surface enhanced Raman spectroscopy (SERS) was obtained. As preliminary studies, having an average of 1000 Raman spectra per tissue, SERS signals showed changes between the HPV-infected and the carcinogenic tissues; these spectral signatures occurred mainly in the DNA bands, potentially offering a tool for the rapid screening of cancer.

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