Correlation between fractal dimension and surface characterization by small angle X-ray scattering in marble.

Among several analysis techniques applied to the study of surface passivation using dicarboxylic acids, small angle X-ray scattering (SAXS) has proved to be relevant in the physicochemical interpretation of the surface association resulting between calcium carbonate and the molecular structure of malonic acid. It is possible to establish chemical affinity principles through bidimensional geometric analysis in terms of the fractal dimension obtained experimentally by SAXS. In this Article, we present results about the adsorption of malonic acid on calcite, using theoretical and mathematical principles of the fractal dimension.

Structural and textural evolution during folding of layers of layered double hydroxides.

Layers of a layered double hydroxide, containing aluminum 4-fold coordinated, were partially folded in order to obtain a fibrous hydrotalcite-like compound. The hydrotalcite layers, in the presence of an anionic surfactant (sodium dodecyl sulfate) after hydrothermal treatment for 2 weeks, acquire a mesoporous-like arrangement. The transformation was monitored by techniques sensitive to structural and textural properties.

Comparative study of regioselective synthesis of beta-aminoalcohols under solventless conditions catalyzed by sulfated zirconia and SZ/MCM-41.

Sulfated zirconia and SZ/MCM-41 were used as catalysts for the synthesis of beta-aminoalcohols via epoxide aminolysis. Sulfated zirconia was prepared by sol-gel and SZ/MCM-41 was obtained by impregnation. Solid catalysts were characterized by XRD, SEM-EDS, UV-Vis, FT-IR pyridine desorption and Nitrogen physisorption.

Passivation of the calcite surface with phenylmalonate and benzylmalonate ions.

We explored the affinity of calcite to adsorbed organic molecules as an approach to the conservation of cultural heritage built of marble and limestone. The utilization of phenylmalonic and benzylmalonic acids provided a hydrophobic adsorptive interface, adequate to prevent processes of aqueous weathering. Samples of marble powder (polycrystalline calcite) were impregnated with solutions of phenylmalonic and benzylmalonic acid at three concentrations (5 x 10(-2), 5 x 10(-3), and 5 x 10(-4) M) and different pH values (6.

Passivation of the calcite surface with malonate ion.

Samples of polycrystalline calcite were impregnated with solutions of malonic acid of three concentrations (5 x 10(-2), 5 x 10(-3) , and 5 x 10(-4) M) and different pH values (6.00, 7.00, and 8.