The aggregation and colloidal stability of three, commercially-available, gamma-aluminum oxide nanoparticles (γ-Al₂O₃ NPs) (nominally 5, 10, and 20-30 nm) were systematically examined as a function of pH, ionic strength, humic acid (HA) or clay minerals (e.g., montmorillonite) concentration using dynamic light scattering and transmission electron microscopy techniques. NPs possess pH-dependent ...

Molecular dynamics simulations, conventional and metadynamics, were performed to determine the interaction of model protein Gb1 over kaolinite (001), Na(+)-montmorillonite (001), Ca(2+)-montmorillonite (001), goethite (100), and Na(+)-birnessite (001) mineral surfaces. Gb1, a small (56 residue) protein with a well-characterized solution-state nuclear magnetic resonance (NMR) structure and havin...

Biohybrid materials based on the intercalation of zein, the major storage protein in corn, into sodium-exchanged montmorillonite were prepared following two synthesis strategies. The first one made use of zein dissolved in 80% (v/v) ethanol/water solution, the usual solvent for this protein, while the second method is new and uses a sequential process that implies the previous separation of zei...

The preparation and characterisation of synthetic enzyme complexes simulating those usually encountered in soil were investigated. Complexes were prepared at 308C by the interaction of acid phosphatase and tannic acid in the presence and absence of Fe and Mn ions (as chlorides) and oxides, with and without montmorillonite. In comparison with phosphatase–tannic acid complexes, the enzymatic comp...

Intercalation of naphthalene and anthracene into alkyltrimethylammonium (C, H2. + ~ (CH3)3N+; n = 8, 12, 14, 16, and 18)-montmorillonites was carried out by novel solid-solid reactions at room temperature. Octyltrimethylammoniurn(C8)-montmorillonite did not form an intercalation compound with either naphthalene or anthracene. Naphthalene was intercalated into both dodecyltrimethylammonium(C12)a...

Monoalkyland dialkyl-imidazolium surfactants were used to prepare organically modified montmorillonites with markedly improved thermal stability in comparison with their alkyl-ammonium equivalents (the decomposition temperatures increased by ca. 100 °C). Such an increase in the thermal stability affords the opportunity to form syndiotactic polystyrene (s-PS)/imidazolium-montmorillonite nanocomp...

The effect of temperature in the range of 0–150 8C was studied for homoionic montmorillonite clays with Na and Csqq compensating ions in low hydration states. Both static and dynamic information concerning the interlayer ions and water moleculeswas obtained by Monte Carlo and molecular dynamics. Principal structural changes were limited to the water phase, markeddifference was o...

-The sorption properties of Co, Cu, Ni, and Ca were studied in a mixed mineral suspension of synthetic MnO2 and Wyoming montmofillonite. The distribution of the sorbed cations between the two solid phases was measured by indirect chemical fractionation with acidified NH2OH-HC1 and by direct X-ray spectroscopic analysis of mineral particles using electron microscopy. Electron microscope and NH2O...

The role of catalysis in prebiotic synthesis is illustrated using the montmorillonite clay catalyzed synthesis of RNA oligomers. Reaction of activated monomers of nucleotides in pH 8 aqueous solution containing Mg2þ in the presence of montmorillonite yields 6–14 mers. The reaction takes place at the clay interlayer. The catalyst controls the synthesis of RNA oligomers in that a limited number o...

Two-dimensional (2D) nanosheets obtained by exfoliating inorganic layered crystals have emerged as a new class of materials with unique attributes. One of the critical challenges is to develop robust and versatile methods for creating new nanostructures from these 2D-nanosheets. Here we report the delamination of layered materials that belonging to two different classes--the cationic clay, mont...