One-pot alkanolamines-assisted synthesis of magnetic mesoporous silica for synthetic dye adsorption.

Magnetic mesoporous silica (MMS) was synthesized in a one-pot system using various alkanolamines (triethanolamine, diethanolamine, tris (hydroxymethyl)aminomethane) as a basic catalyst. The characterization of the composites was conducted using scanning electron microscope, transmission electron microscope, X-ray diffractometer, surface area analyzer, and X-ray photoelectros spectroscopy. The MMS synthesized with tris(hydroxymethyl)aminomethane (MMS) showed the highest specific surface area, pore volume, and average pore diameter.

Bottom-up synthesis of titanophosphate nanosheets by the aqueous solution process.

The synthesis of titanophosphate nanosheets in aqueous sols was examined by the bottom-up process. The nanosheets were formed by mixing titanium iso-propoxide, phosphoric acid, and tetraalkylammonium hydroxide (NROH) aqueous solutions, followed by diluting with water and heating at 80 °C, forming translucent aqueous sols of titanophosphate nanosheets with the same crystal structure as layered titanium phosphate TiO(HPO)·2HO. Whether the nanosheets were crystallized depended on the reactions during the mixing of reagents before the water dilution.

Highly magnetic nanoporous carbon/iron-oxide hybrid materials.

The preparation of size-controllable Fe2O3 nanoparticles grown in nanoporous carbon with tuneable pore diameters is reported. These hybrid materials exhibit strong non-linear magnetic properties and a magnetic moment of approximately 229 emu g(-1), which is the highest value ever reported for nanoporous hybrids, and can be attributed to the nanosieve effect and the strong interaction between the nanoparticles and the carbon walls.

Phase transition between layered tungstates and polyoxotungstates in aqueous solutions.

Aqueous sols of colloidal layered tetramethylammonium (TMA) tungstate nanocrystals were obtained by diluting an aqueous suspension of TMA polyoxotungstate precipitates. The slow evaporation of the colloidal-layered tungstate sols led to the deposition of TMA polyoxotungstate and significantly decreased the amount of layered tungstate nanocrystals. Moreover, the increase in the amount of TMA(+) in the sols also facilitated precipitation of the polyoxotungstates because of a common ion effect.

Diversity in the matrix structure of eggshells in the Testudines (Reptilia).

The eggshells of 56 chelonians were examined by electron microscopy and X-ray diffractometry. They were classified into six types in terms of the matrix structure of their calcareous layer; type I was composed of a thin calcareous layer with minerals in an amorphous structure; type II with shell units composed of mammillary cores calcified with aragonite crystals; type III with shell units composed of mammillary cores, plus a single palisade layer also calcified with aragonite crystals, and with each shell unit separated; type IV with shell units the same as type III, but tightly packed together; type V with shell units composed of mammillary cores plus two palisade layers; and type VI with a cuticle layer calcified with calcite crystals over the same structure as that of type V. X-ray diffraction analyses at the outer surface of eggshells showed a gradual change in crystal disposition from the random disposition of type II to the single direction-oriented disposition of type V.

Synthesis of transparent aqueous sols of colloidal layered niobate nanocrystals at room temperature.

Transparent aqueous sols of colloidal tetramethylammonium niobate nanocrystals were synthesized by mixing tetramethylammonium hydroxide (TMAOH), niobium ethoxide, and water at TMAOH/Nb≥0.7 at room temperature. The X-ray diffraction patterns of the thin films prepared by evaporating the colloidal solutions on a glass substrate indicated that the colloidal niobate had a layered crystalline structure.