Montmorillonite Surface Research Articles

Coupled effects of iron (hydr)oxides and clay minerals on the heterogeneous oxidation of aqueous Mn(II) and crystallization of manganese (hydr)oxides

The formation of nanominerals and mineral nanoparticles (NMMNs) has drawn broad attention due to their high reactivity and omnipresence in the environment. While the heterogeneous formation of NMMNs on surfaces of various minerals has been extensively studied, there is limited understanding of how mineral heteroaggregates influence this process. In this study, we investigated how heteroaggregates of iron (hydr)oxides and clay minerals affect the heterogeneous oxidation of aqueous Mn(II) and crystallization of manganese (hydr)oxides (MnOx). Our results revealed that iron (hydr)oxides (ferrihydrite) and clay minerals (kaolinite or montmorillonite) in heteroaggregates exerted coupled effects on these processes, dictating the distribution of Mn and the morphology of MnOx. Specifically, ferrihydrite catalyzed gradual oxidative removal of Mn(II) and triggered MnOx nucleation; in contrast, kaolinite/montmorillonite rapidly adsorbed Mn(II) but hardly catalyzed its oxidation. These reactions collectively resulted in fast adsorption and gradual oxidation of Mn(II) on the heteroaggregates. Further, MnOx nanoparticles formed on ferrihydrite surfaces migrated to kaolinite/montmorillonite surfaces, leading to interactions between MnOx and various component minerals within the heteroaggregates. This significantly altered the subsequent growth pathways and the eventual morphology of MnOx. Consequently, while MnOx nanoparticles in the ferrihydrite-only system aggregated freely and formed well-extended nanowires, those in the ferrihydrite-kaolinite system predominantly became short nanorods due to the immobilization by kaolinite surfaces; in the ferrihydrite-montmorillonite system, considerable MnOx nanoparticles attached to montmorillonite surfaces due to strong electrostatic attraction, and subsequently grew into blocky particles via particle attachment. These findings illustrate that surface reactivities of heteroaggregated ferrihydrite and kaolinite/montmorillonite are coupled when they interact with aqueous Mn(II) or MnOx. Our work exemplifies, for the first time, the cooperation between surfaces of various minerals during the heterogeneous formation of NMMNs. Findings from this study also enhance our understanding of MnOx formation on surfaces with diverse atomic structures, and contribute to the knowledge of Mn cycling in the environment.

Molecular insights into the formation of carbon dioxide hydrates on the external surface of sodium montmorillonite in the presence of various types of organic matters

To address the urgent challenge of global climate change due to the greenhouse effect resulting from increasing carbon dioxide (CO2) emissions, viable technologies for geological CO2 storage must be developed. Of such technologies, CO2 hydrates holds significant promise for CO2 storage in seabed sediments, which typically contain clay minerals and organic matter (OM). Thus, investigating the structure of clay mineral interfaces and their interactions with OM is crucial for understanding the nucleation and growth of CO2 hydrate in seabed sediments. In this study, molecular dynamics simulations were used to investigate CO2 hydrate formation on the external surface of sodium montmorillonite (Na-Mnt) in the presence of various types of OM. The results show that the Na-Mnt surface adsorbed certain numbers of sodium ions (Na+) and OM molecules. The hydration of Na + disrupted of the hydrogen bond structure of CO2 hydrates, while hydrogen bonds that formed between OM and H2O molecules hindered CO2 hydrate formation. Consequently, CO2 hydrates predominantly formed in the bulk-like solution away from the Na-Mnt. However, the electrostatic interaction between the carboxyl groups of OM and Na+ mitigated the inhibitory effect of Na+ on CO2 hydrate formation. Over all, these findings can serve as a fundamental theoretical basis for understanding the formation and occurrence characteristics of CO2 hydrates in seabed sediments with a rich Mnt content. Such understanding will help to advance the development of CO2 storage technologies utilizing CO2 hydrates in seabed sediments.

Properties of EPDM Nanocomposites Reinforced with Modified Montmorillonite.

Considering the dilemma of obtaining economic and high-performance composites based on non-polar and main-chain-saturated ethylene propylene diene monomer rubber (EPDM), we proposed an effective and universal filler modification and nanocomposite preparation method. Specifically, the montmorillonite (MMT) surface was coated with polydopamine (PDA) to obtain DMMT, which was confirmed by XRD, XPS, FTIR, and TGA. After compounding DMMT gel with the solid EPDM via the gel compounding method, a silane coupling agent, vinyltrimethoxysilane, was introduced to construct covalent interactions between rubber and filler. Compared with the unmodified MMT filler EPDM, the EPDM/DMMT nanocomposite showed much fewer filler aggregates in the matrix. The highest tensile strength of the composites reached 6.5 MPa with 10 phr DMMT, almost 200% higher than that of pure EPDM.

Catalytic pyrolysis of biomass waste using montmorillonite-supported ultrafine iron nanoparticles for enhanced bio-oil yield and quality

The catalytic fast pyrolysis process is a promising method for converting biomass waste into bio-oil, where the catalyst plays a crucial role in determining the yield and quality of the products. In this study, ultrafine iron nanoparticles were incorporated onto a montmorillonite substrate through the pyrolyzing coordinated polymer method to enhance liquid fuel production via catalytic pyrolysis of biomass waste. The catalyst showed a uniform distribution of iron on the montmorillonite surface, indicating that the incorporation was successful. Catalytic pyrolysis led to an increase in liquid yields and a decrease in gas product yields compared to direct pyrolysis. The highest bio-oil yield obtained was 56.9% during the catalytic pyrolysis of corncob, which was found to be particularly well-suited for the production of bio-oil. Furthermore, the proposed reaction pathway was based on identifying the composition of the bio-oil, which was further supported by quantum chemical calculations of chemical bond strength and the likelihood of free radical attacks. These findings demonstrate the potential of using montmorillonite-supported ultrafine iron nanoparticles to enhance bio-oil yield and quality in biomass pyrolysis processes.

Adsorption of 2-4-6.trichlorophenol on montmorillonite surface: ONIOM study

The wastewater contains several chemicals, organic and inorganic molecules, among themolecules, 2.4.6-trichlorophenol, which is a source of contamination. The main aim of this work is to distinguish the process of 2.4.6-trichlorophenol retention with montmorillonite using QM: MM-ONIOM approach and applying local and global reactivity parametersthatare an excellent key for identifying adsorption sites. A weak hydrogen bond between the hydroxyl proton of 2,4,6-trichlorophenol molecule and oxygen atom on the montmorillonite surface, with a specific distance, Hb = 2.66 Å using M06-2X functional) has proved the physical adsorption. Thermochemical analysis reveals the exothermic nature of adsorption process. Negative ΔH values signify heat release and negative ΔG values indicating spontaneity under standard conditions.Theobtained results have proved an agreement with other experimental and theoretical data.

The effects of clays on bacterial community composition during arthropod decay

Fossilization, or the transition of an organism from the biosphere to the geosphere, is a complex mechanism involving numerous biological and geological variables. Bacteria are one of the most significant biotic players to decompose organic matter in natural environments, early on during fossilization. However, bacterial processes are difficult to characterize as many different abiotic conditions can influence bacterial efficiency in degrading tissues. One potentially important variable is the composition and nature of the sediment on which a carcass is deposited after death. We experimentally examined this by decaying the marine shrimp Palaemon varians underwater on three different clay sediments. Samples were then analyzed using 16S ribosomal RNA sequencing to identify the bacterial communities associated with each clay system. Results show that samples decaying on the surface of kaolinite have a lower bacterial diversity than those decaying on the surface of bentonite and montmorillonite, which could explain the limited decay of carcasses deposited on this clay. However, this is not the only role played by kaolinite, as a greater proportion of gram-negative over gram-positive bacteria is observed in this system. Gram-positive bacteria are generally thought to be more efficient at recycling complex polysaccharides such as those forming the body walls of arthropods. This is the first experimental evidence of sediments shaping an entire bacterial community. Such interaction between sediments and bacteria might have contributed to arthropods’ exquisite preservation and prevalence in kaolinite-rich Lagerstätten of the Cambrian Explosion.

Agricultural light-converting anti-icing superhydrophobic coating for plant growth promotion

Agricultural coatings play a crucial role in addressing the global food crisis by significantly improving the plant growth environment, accelerating plant development, and enhancing the biological quality of plants. Nevertheless, there exist constraints in the form of limited sunlight utilization, decreased light transmission caused by surface icing leading to diminished plant photosynthesis, and high cost. In this study, a cost-effective and readily scalable superhydrophobic photothermal light-conversion coating is suggested as a means to improve the light conditions necessary for optimal plant growth. By employing in situ growth of carbon dots (CDs) on the surface and interlayers of montmorillonite (MMT) and hydrolytic polymerization of fluorinated alkyl silane (FAS) on the surface of MMT, light-converting superhydrophobic materials (CDs/MMT) with a micro-nano structure were synthesized. These materials demonstrated broad-spectrum fluorescence emission suitable for utilization by plant photosynthesis. They were dispersed into an epoxy resin (ER) matrix to obtain an agricultural superhydrophobic coating (ER-CDs/MMT). The “light absorption-capture-conversion” effect confers exceptional passive anti-icing and active de-icing properties upon the coating. Furthermore, outdoor planting experiments have demonstrated its capacity to substantially enhance the light environment and enhance the biological quality of soybean and morning glory by leveraging light scattering and conversion characteristics. This underscores its considerable potential for application in the next generation of facility agriculture.

Ice-Unfrozen Water on Montmorillonite Surface: a Molecular Dynamics Study

The ice-water phase transformation process and its composition distribution in frozen soil at the microscale remains unclear. The molecular dynamic (MD) simulation method was employed to study the phase transformation mechanism of water-ice on montmorillonite (Mt) surface at supercooled temperature (230 ∼ 270 K). The interfacial, structural, and dynamic properties of Mt-ice-water system were discussed. The evolution of unfrozen water content with temperature in MD simulation was compared with previous results from NMR experiments for validation. The simulation results showed that 1) the transformation degree of ice into unfrozen water was almost unchanged in 230 ∼ 260 K, while significantly increased when the temperature rose from 260 to 270 K. 2) The surface effect of montmorillonite played an essential role in the existence of unfrozen water in frozen soil, where coulomb electrostatic interaction was the main influencing factor. 3) Total hydrogen bonds in Mt-water-ice system could be broken due to thermal fluctuations of atoms when the temperature gradually rose. 4) The order of liquidity for the three zones was zone ⅲ (quasi-liquid water) > zone ⅰ (bound water) > zone ⅱ (ice).

Mn loading on montmorillonite surfaces for Cd stabilization: Insights from density functional theory calculations and surface complexation modeling

The latest works have been devoted to the stabilization mensuration for heavy metals and indicate that clay minerals can promote Cd(II) precipitation by favoring the retention of Mn(II). The assessment however has been tempered due to lacking the information about the molecular-level surface complexation structure and Cd nucleation process on clay surfaces. In this study, microscopic mechanisms for adsorption and stabilization of Cd at montmorillonite interfaces with or without Mn loading were leveraged by combining surface complexation model (SCM) evaluations and density functional theory (DFT) calculations. Mn(II) substitution resulted in increases in surface acidity equilibrium constant (pKa) by about 1 unit and complexation constant (lgK(SOCd+)) of Cd(II) by about 0.15 units at clay surface, and Mn(II) adion can provide extra active sites (i.e., OH− groups) for complexing Cd(II) via hydrolysis. DFT calculations revealed Mn(II) and Cd(II) adions bind on base surfaces by isomorphic substitutions through weak long-range interactions, whereas on edge surfaces by surface complexation with strong but short-range connections. Adsorption energy calculations and electrostatic distribution showed heterogenous nucleation with subsequent cations on clay surfaces was thermodynamically favored, the stabilization process underwent the steps of the adsorption-hydrolysis-precipitation. The derived results provide a quantitative basis for understanding the precipitation and heterogenous nucleation of cations on clay surfaces in surficial environments.

Influence of cations and low molecular weight organic acids on Cs(I) adsorption on montmorillonite and vermiculite

To predict the mobility of radiocesium (RCs) in the environment, it is essential to understand the adsorption and desorption processes. In this study, we focused on the effects of certain environmental factors, including typical cations (K+, Na+, and NH4+) and low molecular weight organic acids (LMWOAs) such as acetic acid, malic acid, and citric acid on the behavior of RCs on montmorillonite and vermiculite. The results showed that montmorillonite possesses the strongest adsorption capacity for Cs+ than that of vermiculite. Since K+ and NH4+ exhibit similar physicochemical properties to Cs+, there is a significant inhibition of Cs+ adsorption on montmorillonite and vermiculite during the competitive interaction with K+ and NH4+. Compared to NH4Cl, the desorption ratios of Cs+ on montmorillonite and vermiculite are higher in the presence of KCl as the background solution. Low molecular weight organic acids can cover the surfaces of montmorillonite and vermiculite to different extents, which effectively blocks the adsorption sites for Cs+, and leads to an obvious decrease in the adsorption and desorption of Cs+. Due to the high expandable performance, Cs+ is primarily reversibly adsorbed by montmorillonite. Nevertheless, the adsorption of Cs+ on vermiculite exhibits typical irreversible characteristics due to the interlayer collapse. After the adsorption of LMWOAs on montmorillonite and vermiculite, the irreversible adsorption of Cs+ is increased obviously, mainly due to the blocking effect of organic matters on the adsorption sites with high affinity to Cs+.

Cadmium pollution exacerbated by drought: Insights from the nanoscale interaction at the clay mineral surface

Drought is a global environmental problem, while the effect of drought-induced unsaturation on the fate of heavy metal ions is still poorly understood, particularly the lack of mechanistic information at the molecular level. This study used molecular dynamics simulations to investigate nanoscale interactions at the montmorillonite surface under different moisture conditions. Compared to the saturated condition, drought increased the amounts and strength of Cd2+ ions adsorbed on the montmorillonite (MMT) surface while decreased the diffusivity, which was especially obvious in extreme drought conditions (θv=21%−7%). This is closely related to the compressed electric double layer, overcompensation of surface charge, and increased ion pair interactions, resulting from the confinement of water films under drought stress. Further analysis showed that the decrease of hydration effect was responsible for the exacerbated cadmium pollution. Therefore, this study may break the stereotypes about the interactions between heavy metal ions and soil minerals. The results suggest that water management (e.g., irrigation) may be prioritized before beginning heavy metal remediation.

Intercalation of organosilane in clay mineral for the removal of Procion red MX-5B: Investigational and theoretical studies

Finding new materials with specific characteristics such as eco-friendly, low-cost, sustainable, and efficient in wastewater treatment is still challenging. Thus, the present work combines the surface modification and intercalation of [3-(2-aminoethylamino)propyl]trimethoxysilane (TMSPEDA) of natural montmorillonite (Mmt) and its adsorption performance in the removal of Procion red MX-5B from aqueous solution. The modified clay (Mmt@SPEDA; the hybrid of montmorillonite-[3-(2-aminoethylamino)propyl] silane) was also characterised using XRD, FESEM, EDS, pHpzc, FTIR, N2-adsorption/desorption analyses, elemental analysis, TGA/DTG, hydrophobicity-hydrophilicity balance (HI). In order to improve the comprehension of the process intercalation and adsorption mechanism between Procion red MX-5B and Mmt@SPEDA adsorbent, a theoretical analysis of the adsorption phenomenon was performed based on DFT calculation. As a result, the interlamellar spacing of natural clay increased more than 1.50 times after the intercalation process, corresponding to a 50.33 % expansion. The final geometry of the intercalation process reveals that SPEDA molecules are perpendicular to the surface of montmorillonite with a specific orientation interaction between the oxygen atoms of the silanol group of the intercalating molecules and the atoms on the surface of montmorillonite. These interactions are likely electrostatic or correspond to van der Waals forces and hydrogen bonds. The characterisation data confirms the grafting of SPEDA groups on the clay. The positive adsorption energies indicate the endothermic nature of the adsorption process, suggesting that the system absorbs energy during the adsorption of PRMX-5B dye. The Liu's Qmax values for PRMX-5B dye varied from 171.4 and 318.6 mg g−1 for temperatures ranging from 10°–45 °C, demonstrating the excellent properties of the Mmt@SPEDA hybrid adsorbent.

Study on the Effect of Clay Minerals on CO<sub>2</sub> Hydrate Formation

With the massive emission of greenhouse gases, global warming has become an important challenge for human beings at present. Storing carbon dioxide in the form of solid hydrates in the ocean is an effective strategy to mitigate climate warming. Clay in the ocean may have an effect on hydrate formation and CO<sub>2</sub> storage. In this study, montmorillonite and kaolinite were selected as clay minerals, and the effects of clay particles on CO<sub>2</sub> hydrate formation in suspensions with different mass fractions were experimentally analyzed. The results showed that the clay particles were able to promote hydrate nucleation and shorten the induction time, but the final amount of hydrate was reduced, which was related to the bound water. CO<sub>2</sub> hydrate storage in clay minerals with different water contents was investigated. The amount of CO<sub>2</sub> storage in montmorillonite minerals first decreased and then increased with the increase of water content, while the amount of storage in kaolinite minerals increased. The reason was that the amount of bound water on the surfaces of montmorillonite and kaolinite was different, and the stronger bound water was difficult to form hydrates. The results revealed the effect of clay particles on CO<sub>2</sub> hydrate formation and provided some experimental support for the CO<sub>2</sub> storage by hydrate method in the ocean.

The surface and interlayer modification of montmorillonite and its potential application for thermal energy storage

Phase change materials (PCMs) could take full advantage of clean and renewable energy, because of their ability to convert and store various energy. However, due to the leakage and low heat storage capacity, the large-scale commercial application of PCMs is seriously limited. In this work, natural montmorillonite (MMT) was modified by organic amine coupling agent that was assembled into the interlayer of MMT. The energy storage performance and the stability of composite PCMs were significantly improved by using a novel frame of MMT encapsulated Paraffin (PA). The MMT-KH550-HAc/PA composite PCMs prepared by organic intercalation provides suitable pore structure and hydrophilicity to encapsulate more PA, resulting in the highest latent heat capacity (150 J/g) that is significantly increased by 144.1% from 60 J/g. Meanwhile, the energy storage stability of MMT-KH550-HAc/PA is also improved, and the latent heat of phase change is reduced by 3.2% after 100 cycles. The present MMT-KH550-HAc/PA has remarkable latent heat capacity and energy storage stability, which can be potentially applied to the solar water heaters.

First-principles study on the effect of pressure on the adsorption of H2O on the Mg-montmorillonite (010) surface

The effect of pressure on H2O adsorption on the montmorillonite surface is a crucial issue in geomechanics and high-pressure physics. In this paper, the effect of pressure on adsorption capability were calculated based on density-functional theory (DFT) for pressures ranging from 0 to 18 GPa, and the adsorption energies and structures of the H2O molecules were analyzed with different surface coverages (0 < Θ ≤ 1.0 ML). Firstly, the clean (010) surface of Mg-montmorillonite was modelled at different pressures from an atomic perspective, then the calculations demonstrated that single H2O molecules were stably adsorbed on the top, bridge, hollow and interlayer bridge sites, independent of pressure. However, the adsorption energies at different sites were significantly influenced by the pressure and showed different trends. For the hollow and bridge sites, the adsorption energy increased within the pressure range 0–2 GPa but decreased within the pressure range 2–18 GPa. Conversely, for the top sites, the adsorption energy decreased with increasing pressure within the range 0–2 GPa but increased with increasing pressure within the range 2–18 GPa. For increasing coverage with H2O molecules, the adsorption energy was almost constant at 0 GPa but decreased within the range 0 < Θ ≤ 1.0 ML at 2, 10, and 18 GPa. Furthermore, the adsorption energies for the bridge sites all increased with increasing coverage but decreased with increasing coverage for the interlayer bridge sites at the four pressures. In addition, other characteristics of the H2O and Mg-montmorillonite (010) surface were discussed, including bonding, changes in the electronic density of states, the charge distribution, and the structure of the atomic interlayer at different pressures.

Shrinkage Reduction in Nanopore-Rich Cement Paste Based on Facile Organic Modification of Montmorillonite.

The organic modification of montmorillonite was successfully achieved using cetyltrimethyl ammonium bromide under facile conditions. The modified montmorillonite was subsequently used for the fabrication of montmorillonite-induced nanopore-rich cement paste (MNCP), and the shrinkage behavior and fundamental performance of MNCP were also investigated. The results indicate that alkali cations on a montmorillonite layer surface were exchanged by using CTAB under 80 °C, successfully achieving the organic modification of montmorillonite. As a pore-forming agent, the modified montmorillonite caused a reduction in shrinkage: the 28-day autogenous shrinkage at a design density of 400 kg/m3 and 800 kg/m3 was reduced to 2.05 mm/m and 0.24 mm/m, and the highest reduction percentages during the 28-day drying shrinkage were 68.1% and 62.2%, respectively. The enlarged interlamellar pores and hydrophobic effects caused by the organic modification of montmorillonite aided this process. Organic-modified montmorillonite had a minor influence on dry density and thermal conductivity and could contribute to an enhancement of strength in MNCP.

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

Abstract Dodecyl dimethyl benzyl ammonium (DDBA) is a novel cation surfactant used to modify clay minerals. DDBA-intercalated montmorillonite is formed by the ion exchange between DDBA cations in the solution and cations in the montmorillonite interlayers. By using molecular dynamics simulations, we investigated the basal spacings, interlayer structures and dynamics of DDBA-montmorillonites. The results showed that the calculated basal spacings agreed well with experimental values and that the layering behaviours of DDBA had been revealed. The ammonium groups of DDBA ions preferred staying close to the centre of Si–O six-member rings. The benzyl group and lauryl group were oriented in parallel in the monolayer state, whereas they were tilted in other states. DDBA ions have very low mobility in the interlayer region, indicating that the negatively charged montmorillonite surfaces can effectively fix this positively charged surfactant. The microscopic structures and dynamics obtained in the present study provide atomic-scale insights into the properties of DDBA-intercalated clay minerals.

H2S-Releasing Versatile Montmorillonite Nanoformulation Trilogically Renovates the Gut Microenvironment for Inflammatory Bowel Disease Modulation.

Abnormal activation of the intestinal mucosal immune system, resulting from damage to the intestinal mucosal barrier and extensive invasion by pathogens, contributes to the pathogenesis of inflammatory bowel disease (IBD). Current first-line treatments for IBD have limited efficacy and significant side effects. An innovative H2S-releasing montmorillonite nanoformulation (DPs@MMT) capable of remodeling intestinal mucosal immune homeostasis, repairing the mucosal barrier, and modulating gut microbiota is developed by electrostatically adsorbing diallyl trisulfide-loaded peptide dendrimer nanogels (DATS@PDNs, abbreviated as DPs) onto the montmorillonite (MMT) surface. Upon rectal administration, DPs@MMT specifically binds to and covers the damaged mucosa, promoting the accumulation and subsequent internalization of DPs by activated immune cells in the IBD site. DPs release H2S intracellularly in response to glutathione, initiating multiple therapeutic effects. In vitro and in vivo studies have shown that DPs@MMT effectively alleviates colitis by eliminating reactive oxygen species (ROS), inhibiting inflammation, repairing the mucosal barrier, and eradicating pathogens. RNA sequencing revealed that DPs@MMT exerts significant immunoregulatory and mucosal barrier repair effects, by activating pathways such as Nrf2/HO-1, PI3K-AKT, and RAS/MAPK/AP-1, and inhibiting the p38/ERK MAPK, p65 NF-κB, and JAK-STAT3 pathways, as well as glycolysis. 16S rRNA sequencing demonstrated that DPs@MMT remodels the gut microbiota by eliminating pathogens and increasing probiotics. This study develops a promising nanoformulation for IBD management.

Insight on the stability of methane hydrate in montmorillonite slits by molecular dynamics simulations

The extent of interactions between clay surfaces and water molecules and their impact on hydrate stability in clay reservoirs have been a source of debate. This study employs molecular dynamics simulations to investigate the stability of methane hydrates in montmorillonite slits at various temperatures, focusing on the surface influence scale, bound water molecule distribution characteristics, and binding strength. The results reveal that hydrates in close proximity to the clay surface exhibit lower stability and higher decomposition susceptibility due to the hydrophilic nature of the surface, which leads to water molecule aggregation, driving methane molecules away during decomposition. Furthermore, we compare the charged and neutral tetrahedral layer surfaces of montmorillonite and find that the quasi-liquid layer on the neutral tetrahedral layer surface is thinner, with persisting semicage structures within the vacancies of the Si-O rings. These variations in surface influence range and binding strength can be attributed to intermolecular Coulomb interactions and charge redistribution at the interface. These research findings provide valuable molecular insights into the microscopic characteristics and behavior of hydrates within clay slits.

Experimental and theoretical studies of the interactions of alanine onto surfaces of olivine and montmorillonite: relevance in astrobiology

Abstract Amino acids have been detected in some meteorites and are readily synthesized in prebiotic experiments. These molecules may have been precursors of oligomers and polymers in the early Earth. These reactions were likely to happen in the protected confined spaces on the porous surface of olivine and in the interlayer nanospace of montmorillonite. This study describes experimental and theoretical research on the sorption of l-alanine onto surfaces of silicate minerals, olivine and montmorillonite. Kinetics of the sorption of this amino acid at different pH media was performed. This sorption has been also studied at atomic scale by means of quantum mechanical calculations finding that this sorption is energetically favourable. These results strongly support the premise that minerals could have actively participated in prebiotic reactions.