The formation of water-in-water emulsions from the aqueous two phase system containing polyethylene oxide and pullulan, stabilised by montmorillonite platelets, was investigated. A novel approach of preparing the emulsions at non-equilibrium polymer concentrations was successfully utilised to control viscosity during mixing and allow the use of low energy emulsification methods. Polyethylene ox...

Novel, low density structures which combine biologically-based fibers with clay aerogels are produced in an environmentally benign manner using water as solvent, and no additional processing chemicals. Three different reinforcing fibers, silk, soy silk, and hemp, are evaluated in combination with poly(vinyl alcohol) matrix polymer combined with montmorillonite clay. The mechanical properties of...

In this work we investigate some aspects of the rheological behavior of sodium montmorillonite (NaMt) suspensions in the pH range 3 to 9, of NaCl concentrations between 10(-3) and 10(-1) M, and of solid concentrations between 5 and 11% w/v. Three kinds of experiments were performed: steady-state viscometry, oscillatory test, and creep recovery. The physical quantities of interest were the yield...

Plutonium (Pu) adsorption to and desorption from mineral phases plays a key role in controlling the environmental mobility of Pu. Here we assess whether the adsorption behavior of Pu at concentrations used in typical laboratory studies (≥10(-10) [Pu] ≤ 10(-6) M) are representative of adsorption behavior at concentrations measured in natural subsurface waters (generally <10(-12) M). Pu(V) sorpti...

The clay montmorillonite is known to catalyze the polymerization of RNA from activated ribonucleotides. Here we report that montmorillonite accelerates the spontaneous conversion of fatty acid micelles into vesicles. Clay particles often become encapsulated in these vesicles, thus providing a pathway for the prebiotic encapsulation of catalytically active surfaces within membrane vesicles. In a...

An array of pioneering research, dealing with various aspects of soil chemistry, has appeared in Soil Science for the past 90 years. In this review, two papers that have shaped the field forever are featured and discussed. The paper by Mattson (1931) and the many others that he published in Soil Science established the importance of variable or pHdependent surface charge on colloids and soils a...

Adsorption of quinoline (pKa 5 4.92) and background electrolyte (CaCl2) onto specimen kaolinite and montmorillonite were measured as a function of pH (3–7.5) and ionic strength (1–10 mM), and as a function of quinoline concentration (0.2–1.55 mM) at fixed pH values of maximum adsorption. Maximum sorption of quinoline occurred at pH 3.5–4.0 for kaolinite, and pH 3.0–5.0 for montmorillonite. At t...

Measuring and modeling the surface charge of clays, and more especially smectites, has become an important issue in the use of bentonites as a waste confinement material aimed at retarding migration of water and solutes. Therefore, many studies of the acid-base properties of montmorillonite have appeared recently in the literature, following older studies principally devoted to cation exchange....

Dolomite or calcite, quartz and kaolinite in various proportions were reacted at 250-300~ temperatures and pressures up to 90 bars in a hydrous environment. Reactions which approached completion produced talc, calcite, montmorillonite, anorthite (both metastable hexagonal and stable triclinic polymorphs) and the rare Ca-zeolite, garronite. These reactions are applicable to diagenesis, low-grade...

The ice nucleation characteristics of montmorillonite mineral dust aerosols with and without exposure to ammonia gas were measured at different atmospheric temperatures and relative humidities with a continuous flow diffusion chamber. The montmorillonite particles were exposed to pure (100%) and diluted ammonia gas (25 ppm) at room temperature in a stainless steel chamber. There was no signific...