-To eliminate mercury vapor from gas streams, three major methods are used: condensation, absorption, and adsorption. This work deals with adsorption, using elemental sulfur as an active phase supported on sepiolite and palygorskite fibrous clays. Sulfur loads of 5-30% were deposited by catalytic oxidation of hydrogen sulfide at temperatures of < 200~ the clays acting first as a catalyst of the...

The crystal structures and hydraulic activities of β and γform dicalcium silicates (β-C2S, γ-C2S) were analyzed by ab-initio calculation based on quantum mechanics. The mean distances less than 4 Å to the neighboring Ca atoms for all of independent Ca atoms were calculated within unit cell. Ca-Ca mean distances are 3.56 Å in β-C2S and 3.75 Å in γ-C2S. The shortening of Ca-Ca distance causes ins...

Ground and space born spectroscopic observations have shown that crystalline Mg-rich silicates are among the main components of cometary grains. We have produced amorphous Mg-rich pyroxene particles by laser evaporation of natural mineral. Thermal annealing of the material has been performed at 800 and 1000 ◦C for different time lags. Composition and morphological properties of the samples have...

This is a safety assessment of silica and the related cosmetic ingredients: alumina magnesium metasilicate, aluminum calcium sodium silicate, aluminum iron silicates, hydrated silica, and sodium potassium aluminum silicate. These ingredients are synthetic amorphous silicas and silicates; crystalline silica is not a cosmetic ingredient and is not used in cosmetics. These ingredients are used as ...

[1] Using first principles quasi-harmonic theory, we have investigated the vibrational and thermodynamic properties of P21/c and C2/c MgSiO3 clinoenstatites. Very good agreement between experimentally measured thermodynamic properties, such as equation of state, and those predicted by the local density approximation (LDA) functional has been found. The level of agreement found in these chain si...

We report on laboratory measurements of molecular hydrogen formation and recombination on an olivine slab as a function of surface temperature under conditions relevant to those encountered in the interstellar medium. On the basis of our experimental evidence, we recognize that there are two main regimes of H coverage that are of astrophysical importance; for each of them we provide an expressi...

We used thermochemical equilibrium calculations to predict Water vapor, present at 30–45 parts per million by volstabilities of pure rock-forming hydrous silicates on Venus’ ume (ppmv) in Venus’ subcloud atmosphere (Drossart surface as a function of elevation, atmospheric H2O and SO2 concentrations, and oxygen fugacity (fO2). About 50 different et al. 1993; Pollack et al. 1993; DeBergh et al. 1...

We study the hydrogen mobility in ringwoodite and wadsleyite considering multiple charge-balanced defects, including Mg < = > 2H, Si < = >Mg+ 2H, and the hydrogarnet defect, Si < = > 4H, using molecular dynamics simulations based on the density functional theory at transition zone pressures and temperatures between 1500 and 2500 K. We determine the diffusion coefficients and study in detail the...

CO2 sequestration may be an avenue to mitigate climate change. CO2 sequestration by mineral carbonation can be achieved by the reaction of CO2 with alkaline silicates. Here, we evaluate how alkaline silicate mineral-based CO2 sequestration can be achieved using environmental biotechnological processes. Several biotechnological processes rely on the sequence of (i) an acid-producing reaction suc...