Zeolite NaA nanocrystals with a narrow particle size distribution were prepared by template-free hydrothermal synthesis in thermo-reversible methylcellulose gels. The effects of the amount of methylcellulose, crystallization time and hydrothermal treatment temperature on the crystallinity and particle size distribution of the zeolite NaA nanocrystals were investigated. We found that the thermog...

The formation and growth of maghemite (γ-Fe2O3) nanoparticles from ammonium iron(III) citrate solutions (C(6)O(7)H(6) · xFe(3+) · yNH(4)) in hydrothermal synthesis conditions have been studied by in situ total scattering. The local structure of the precursor in solution is similar to that of the crystalline coordination polymer [Fe(H(2)cit(H2O)](n), where corner-sharing [FeO(6)] octahedra are l...

The synthesis protocols for encapsulation of metal clusters reported here expand the diversity in catalytic chemistries made possible by the ability of microporous solids to select reactants, transition states, and products on the basis of their molecular size. We report a synthesis strategy for the encapsulation of noble metals and their oxides within SOD (Sodalite, 0.28 nm × 0.28 nm), GIS (Gi...

In this research, zeolite Na-Y was synthesized from Kaolin without an organic template under the non-hydrothermal condition to adsorb sulfur compound. Model fuel desulfurization was optimized by employing the Box-Behnken experimental design with 2 center points, the three parameters, and one response value. The objective was to find how sorption capacity is related to alkali fusion temperat...

The origin of analcite-bearing lavas and potassic volcanic rocks is controversial in the geological record. Two main hypotheses are either primary analcite or replacement pseudomorphous of leucite. Spectacular large (5 cm) euhedral trapezohedra occur as single crystals of analcite in tephriphonolite lavas from Nadik area. Based on the following evidences the large analcite trapezohedra from Nad...

Nowadays, hydorxyapatite (HA) is widely used as bioceramics in reconstructive surgery, in dentistry and as drug delivery materials due to the good biocompatibility and osteoconductivity [Hench, 1998]. One of the limitations for the usage of these materials is their low mechanical strength. Thus, many researchers focuses on the development of new biomaterials, that combine the osteoconductive ch...

Agave sisalana (sisal) is known worldwide as a source of hard fibers, and Brazil is the largest producer of sisal. Nonetheless, the process of removing the fibers of the sisal leaf generates 95% waste. In this study, we applied chemical sequential steps (hydrothermal extraction, precipitation, liquid-liquid extraction, crystallization, SiO2 and Sephadex LH 20 column chromatography) to obtain pe...

Magnesium-substituted fluorapatite powders were synthesized by hydrothermal method, and their sintering behavior was investigated by dilatometry in the temperature range 25-1100°C. Analysis of the obtained powders by X-ray diffraction and (31)P NMR spectroscopy showed that the powders consisted of a single apatite phase and no amorphous phase has been formed. Compared to pure fluorapatite, the ...

A series of H-SAPO-34 zeolites were synthesized by a hydrothermal method in fluoride media. The as-synthesized H-SAPO-34 zeolites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 physisorption, temperature-programmed desorption of NH3 (NH3-TPD) and nuclear magnetic resonance (NMR) measurements. The results showed that a certain concentration of F(-) anions p...

The Xihuashan granitic complex (southern China) is mainly composed of coarse-grained porphyritic biotite granite (G–a), medium-grained porphyritic biotite granite (G–b), and mediumto fine-grained porphyritic biotite granite (G–c). The G–a granite is characterized by monazite-(Ce) and xenotime-(Y), in addition to commonly observed zircon and uranoan thorite. In the G–b and G–c intrusive units, m...