We have examined the nature and origin of smectites in glaciomarine sediments of the AND-2A drill core (McMurdo Sound, Antarctica) by means of X-ray diffraction (XRD) analyses on the clay fraction, field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM) observations and SEM-EDS microanalyses on smectite particles. Relying on the smectite variation throughout the ...

Nitroaromatic compounds (NACs) are prominent soil and sediment contaminants that are strongly adsorbed by smectites at extents that depend on hydration properties of the exchangeable cation. Potassium smectites adsorb nitroaromatics much more strongly than calcium smectites, so that adjustment of K+ versus Ca2+ occupation on cation exchange sites in smectites can be used to modulate the retenti...

Clay minerals, which totally make up 4-5% of the earth’s crust, are generally classified into three different phyllosilicate: illites, smectites and kaolins. Of these, kaolin generally has the lowest Fe content and illite the highest; however, smectite also has appreciable Fe contents (<30 wt %). In this editorial, the focus is restricted to the Fe-bearing smectites, since smectites are ubiquit...

-A complete conversion series for mica/smectites was found in a hydrothermal alteration envelope around Kuroko-type ore deposits at the Shinzan area, Akita Prefecture, Northeast Japan. The minerals are an alteration product of volcanic glass of Miocene age and are commonly associated with zeolites and silica minerals. Degrees of ordering of interstratification of the minerals change discontinuo...

The unusual behaviour of smectites, their ability to change volume when wetted (swelling) or dried (shrinking), makes soil rich in smectites very unstable and dangerous for the building industry due to possible or likely movement of building foundations and poor slope stability. These macroscopic properties are dominated by the structural arrangement of smectites finest fraction. Here, we show ...

The purpose of this paper was to evaluate the possible use of three types of pharmaceutical grades of phyllosilicates as pharmaceutical excipients. Seven samples (two smectites, three palygorskites, and two sepiolites) were studied. A complete mineralogical and chemical characterization of each material was made and powder texture was established by image analysis of scanning electron micrograp...

An understanding of sorptive processes is key to describing the fate of chlorpyrifos [O,O-diethyl-O-(3, 5, 6-trichloro-2-pyridyl) phosphorothioate] in aquatic environments. The objectives of this study were to evaluate isotherms for adsorption and desorption of chlorpyrifos on colloidal materials and to advance understanding of interaction mechanisms between chlorpyrifos and colloidal materials...

-The acid-catalyzed reaction between methanol and isobutene to give methyl-t-butyl ether may be carried out using a cation-exchanged smectite as the catalyst. In 1,4-dioxan solvent at 60~ smectites exchanged with A13+, Fe 3+, or C# + give yields of -60% after 4 hr, whereas smectites exchanged with Cu 2+, Pb 2+, Ni 2+, Co 2+, Ca 2+, and Na + give less than -8% yield. The reaction is efficient on...

-Protein complexes of smectites in soils are difficult to detect if the usual smectite tests show no peculiarities. Andalusian black earths are typical examples. Investigation of the alkylammonium derivatives, however, allows detection of adhered macromolecules which might be protein-like although this cannot be proved cxactly. Investigation of artificial clay-protein complexes reveals differen...