This paper presents research on the surface characteristics, specific surface area (SSA), cation exchange capacity (CEC) and the electrophoretic mobility (EPM) of kaolin clays obtained from different naturally occurring pegmatite and granite deposits worldwide. Particular emphasis was placed on studying the influence of ancillary minerals on these properties, as well as the diversity in morphol...

[1] Phyllosilicates have previously been detected in layered outcrops in and around the Martian outflow channel Mawrth Vallis. CRISM spectra of these outcrops exhibit features diagnostic of kaolinite, montmorillonite, and Fe/Mg-rich smectites, along with crystalline ferric oxide minerals such as hematite. These minerals occur in distinct stratigraphic horizons, implying changing environmental c...

The ultimate concern over pesticides in the environment is their toxic impact on nontarget organisms, including humans. Soil clays are known to interact with pesticides in ways that decrease the concentration of the parent compound in the soil solution (adsorption, sequestration, degradation). These phenomena are generally regarded as beneficial, but toxicological verification is lacking. In th...

Hydrolysis of chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate] to TCP (3,5,6-trichloro-2-pyridinol) is an important degradation process influencing the fate of chlorpyrifos in aquatic environments. The effects of water chemistry and suspended colloids (smectites, humic acid, and river sediment) on the hydrolysis of chlorpyrifos were investigated in this study. Chlorpyri...

We have established an extracorporeal bowel model system for the analysis of early events in inflammatory bowel disease (IBD) and therapeutic applications. This model consists of an intestinal segment that is cannulated and perfused in situ, allowing the investigation of cellular responses of apical mucosa cells on luminal applied substances. Short-term treatment with iodoacetamide mimicked exp...

[1] Nili Fossae is a region with fresh exposures of old material. OMEGA spectral data have revealed a strong diversity of minerals in the Nili Fossae region, including mafic minerals and phyllosilicates. Phyllosilicates are found to be primarily Fe-rich smectites (a type of clay minerals). These phyllosilicates are observed only on the Noachian crust, in four types of locations: Three are witho...

-The use of Derjaguin-Landau-Verwey-Overbeek (DLVO) theory in colloid science has continued to the present day in spite of the inability of this theory to explain, even qualitatively, numerous phenomena exhibited by clays and other colloidal materials. An alternative description of the fundamental forces involved in the formation of dispersions and gels was presented in 1938 by Langmuir, but wa...

-Ion-exchange experiments in expanding clay minerals conducted over a wide range of surface ionic compositions and ionic strength produce variable mass-action selectivity coefficients. When the exchanging ions are of unequal charge, tactoid structure appears to influence selectivity, although configurational entropy of adsorbed ions may also generate variable selectivity. The degree of deviatio...

The smectites represent a versatile class of clay minerals with broad usage in industrial applications, e.g., cosmetics, drug delivery, bioimaging, etc. Synthetic hectorite Na0.7(Mg5.5Li0.3)[Si8O20](OH)4 is a distinct material from this class due to its low-cost production method that allows to design its structure to match better the applications. In the current work, we have synthesized for t...

Cysteine and toluene as model organic molecules were intercalated into Fe-rich smectite (nontronile, NAu-2). The illitization of these intercalated smectites as induced by microbial reduction of structural Fe" was investigated. Iron-reducing bacterium Shewanellaputrefaciens CN32 was incubated with lactate as the sole electron donor and structural Fe* in cysteineand toluene-intercalated NAu-2 (r...