Infrared reflection absorption spectroscopy (IRRAS), also called infrared external reflection spectroscopy, is used for studying ultrathin hybrid clay films prepared by the Langmuir–Blodgett (LB) method. Infrared spectra of the hybrid films have been obtained at the air–water and air–solid (gold) interface. The presence of a smectite monolayer is observed when cationic surfactants are spread ov...

Smectite-rich clay is a major engineered barrier (buffer) in repositories for heat-producing highly radioactive waste. It has the form of densely compacted blocks of clay granules and is only partly water saturated from start. The initial porewater is redistributed by the thermal gradient acting in the buffer and additional water is taken up to give ultimately complete saturation. The compactio...

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...

Complexes of 1,4-diazabicyclo [2.2.2] octane (triethylene diamine) with smectite and vermiculite were made for the purpose of exposing the internal surfaces of the clays for adsorption of gases and possible catalytic activity. When the diprotonated form of the amine saturated the exchange sites, internal surfaces of the clays were found to be available to nitrogen, ethane, and 2,4-dimethyl pent...

The development of lowand hightemperature alteration products in a 23 m section of ocean-floor basalts is described. Analcime, calcite and dioctahedral smectite are ubiquitous. Trioctahedral smectite, smectite-chlorite mixed layers, chabazite and scolecite occur in the deeper sections with Fe 3+ oxides/ hydroxides progressively becoming more abundant in the upper regions. The upper layers of th...

Myanmar has a drier sub-tropical climate than countries that typically contain Ni laterite deposits, but hosts deposit at Tagaung Taung. Given enrichment processes in the Taung are poorly understood, we investigated geochemical and mineralogical evolution of two weathering profiles developed on different bedrocks central part Myanmar: partly serpentinized harzburgite an almost completely perido...

Effects of radiation-induced amorphization of smectite were investigated using artificial irradiation. Beams of 925 MeV Xenon ions with radiation dose reaching 73 MGy were used to simulate the effects generated by alpha recoil nuclei or fission products in the context of high level nuclear waste repository. Amorphization was controlled by X-ray diffraction, transmission electron microscopy, and...

– Microscopy observations show that suspensions of synthetic and natural nanolayered smectite clay particles submitted to a strong external electric field undergo a fast and extended structuring. This structuring results from the interaction between induced electric dipoles, and is only possible for particles with suitable polarization properties. Smectite clay colloids are observed to be parti...