Interaction between glycine and Na-, Caand Cu-rich smectites

Benincasa, Emanuele; Brigatti, Maria Franca; Lugli, Cristina; Medici, Luca; Poppi, Luciano

doi:10.1180/000985500547098

Cited by 12 publications

(5 citation statements)

References 20 publications

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“…ALA is an amino acid analog that carries a carboxyl and an amino functional group, which should be zwitterionic (Lilley, 1985). Protonated ALA may enter the NAu-2 interlayer via two mechanisms (Benincasa et al, 2000). First, protonated ALA can substitute for water molecules in the nontronite interlayer such that NAu-2 becomes hydrophobic (Goebel et al, 2004;Jandl et al, 2004;Chou et al, 2005).…”

Section: Effects Of Ala Intercalation On Bioreduction and Methanogenesismentioning

confidence: 99%

The role of Fe(III) bioreduction by methanogens in the preservation of organic matter in smectite

et al. 2014

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Organic matter in sediments is largely associated with clay minerals and can be preserved over geological time. However, microbial activity can possibly influence this association and release organic matter from clay minerals via reductive or oxidative dissolution of clay minerals. In this study, the relationship between bioreduction of structural Fe(III) in smectite and organic matter release from smectite structure was investigated. A model organic compound, 12-aminolauric acid (ALA) was intercalated into the interlayer region of an iron-rich smectite (nontronite, NAu-2). Two methanogens: mesophilic Methanosarcina mazei and thermophilic Methanothermobacter thermautotrophicus were selected to reduce structural Fe(III) in ALA-intercalated nontronite. As a comparison, sodium dithionite was used to chemically reduce structural Fe(III) in the same mineral. The results showed that the intercalation of ALA into the nontronite interlayer decreased both the rate and the extent of Fe(III) bioreduction. Furthermore, methanogenesis was more inhibited by the presence of intercalated ALA in the nontronite structure relative to pure nontronite. After the bioreduction, the intercalated ALA was partially released, and the extent of release was positively correlated with the extent of Fe(III) reduction. A low reduction extent of bioreduction (b 30%) resulted in little ALA release, whereas a nearly complete chemical reduction by sodium dithionite released all intercalated ALA. SEM observations and aqueous chemistry data suggested that reductive dissolution was a main mechanism for the observed ALA release. Because naturally prevalent biological reduction is a slow process with a low reduction extent relative to chemical reduction, the results of this study demonstrated that organic matter preserved within smectite structure should not be released by the mechanism of iron reduction.

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Section: Effects Of Ala Intercalation On Bioreduction and Methanogenesismentioning

confidence: 99%

The role of Fe(III) bioreduction by methanogens in the preservation of organic matter in smectite

et al. 2014

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“…We hypothesize that organics could impact the growth and properties of these structures, specifically through interactions on the surface of the chemical garden interior and/or exterior. Amino acids have been known to interact with a variety of surfaces, including metals and minerals. − Iron minerals are particularly prone to binding organic compounds, and specifically amino acids, − so we hypothesized that the functional groups on the amino acids and the concentration of the amino acids could significantly impact the structure of the iron-silicate chemical gardens.…”

Section: Introductionmentioning

confidence: 99%

Effects of Amino Acids on Iron-Silicate Chemical Garden Precipitation

et al. 2020

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Understanding the structure and behavior of chemical gardens is of interest for materials science, for understanding organic−mineral interactions, and for simulating geological mineral structures in hydrothermal systems on Earth and other worlds. Herein, we explored the effects of amino acids on inorganic chemical garden precipitate systems of iron chloride and sodium silicate to determine if/how the addition of organics can affect self-assembling morphologies or crystal growth. Amino acids affect chemical garden growth and morphology at the macro-scale and at the nanoscale. In this reaction system, the concentration of amino acid had a greater impact than the amino acid side chain, and increasing concentrations of organics caused structures to have smoother exteriors as amino acids accumulated on the outside surface. These results provide an example of how organic compounds can become incorporated into and influence the growth of inorganic self-organizing precipitates in far-from-equilibrium systems. Additionally, sample handing methods were developed to successfully image these delicate structures.

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“…Many studies on the adsorption of amino acids on montmorillonite were published lately (Naidja and Huang, 1994;Brigatti et al, 1999;Benincasa et al, 2000;Kollár et al, 2003;Benetoli et al, 2007;Han et al, 2007;Parbhakar et al, 2007;Mallakpour and Dinari, 2011;Ramos and Huertas, 2013). The results suggest that the structure and properties of prepared organoclays are influenced also by the charge of the amino acid side-chain (R) and the structure of the used montmorillonite.…”

Section: Introductionmentioning

confidence: 84%