Determination of layer charge density in expandable phyllosilicates with alkylammonium ions: A combined experimental and theoretical assessment of the method

Experimental investigations of the preservation/degradation of microbial signatures in the presence of clay minerals under Martian subsurface conditions

“…Of note, the interlayer space of the saponite in the residues produced at 150°C in the presence of E. coli cells decreases as the experimental duration increases (from 1 to 100 days -Fig. 5), suggesting a reduction of the amount and/or the size of the organic compounds trapped within interlayer spaces (Lanson et al, 2022). This trend is consistent with EA-irMS results, indicating a decreasing TOC and TN content with increasing experimental duration (Table 1, Fig.…”

Interaction between clay minerals and organics in asteroid Ryugu

“…N heterocyclic compounds, which can form positively charged ions, were found in Ryugu (E. and N-bearing organic compounds were detected in a fluid inclusion in a Ryugu pyrrhotite crystal (T. . Note that, similar d-spacing can be obtained for different types of organic molecules and smectite structures (Lanson et al, 2022), which does not allow us to investigate further the nature of organics within the interlayer space of Ryugu's smectite. Achieving a better understanding of the link between the nature of NH organics and smectite structure related to FTIR and XRD behaviours will require many additional experimental studies.…”

“…In order to provide an explanation for this puzzling spectroscopic feature of Ryugu, we measured a ∼500 μm-sized sub-part of the grain C-0061 of Ryugu, and grains several hundred μm in size of the Orgueil CI chondrite meteorite (fell in 1864) by X-Ray diffraction (XRD) under different relative humidities. Such XRD experiments allow investigation of the presence of water molecules or organics within the interlayer space of smectite layers (Viennet et al, 2019(Viennet et al, , 2020(Viennet et al, , 2022Lanson et al, 2022).…”

Molecular dynamics simulation of dodecyl dimethyl benzyl ammonium cation-intercalated montmorillonite

“…The calculated cleavage energies and their Coulomb and van der Waals contributions were found to be in good agreement with experimental results (Giese & Van Oss, 2002;Yariv & Cross, 2002). Lanson et al (2022) simulated the behaviour of alkylammonium in the Mnt interlayer using Amber-ClayFF force fields (Cornell et al, 1995;Pearlman et al, 1995;Cygan et al, 2004) and obtained stable configurations; the calculated basal spacing were close to experimental values (Lagaly & Weiss, 1971;Lagaly, 1994). Liu et al (2007) investigated the swelling behaviour of alkylammonium-intercalated smectites as a function of carbon chain length by using the combined ClayFF-CVFF force field (Dauber-Osguthorpe et al, 1988;Cygan et al, 2004).…”