[en] Full text: Calcium phosphates are essential components in the development of bioactive materials because of their perfect biocompatibility, their ability to bio-degradation and their biological reactivity. In fact, their chemical compositions are similar to the hard tissue of bone and teeth. Besides above biological properties, the Ca-P-based biomaterials found bear osteoinductive ability after processed into special interconnecting porous and specific surface structures (To some extent this structure is inspired from cancellous/spongy bone tissue) [1]. We are now developing work on essentially two types of these materials as bone substitutes: bioceramics based on hydroxyapatite and tricalcium phosphate from natural substances abundant in the country. We are interested in the synthesis of a macroporous calcium phosphate-carbonated apatite. It is for its biological properties, its availability and low cost as well as its physico-chemical. In our work, we use the microwave-hydrothermal method, which enables to synthesize the ultra fine and high purity powders for shortening working time. This method has some advantages such as heating throughout the media, rapid heating, fast reaction, high yield, excellent reproducibility, narrow particle distribution, high purity and high efficient energy transformation , and being environmentally cleaner. The physical and chemical analyses were carried out on the dried precipitate and the powder calcined at 900 degree. The phases formed were identified by the time of heating in microwave, determined by infrared spectroscopy and by X-ray diffraction. The software used for data processing of X-ray diffraction was DIFFRACT-AT.

[en] Silica gel supported titanium dioxide particles (TiO₂-SiO₂) prepared by sol-gel method was as photocatalyst in the degradation of β-naphthol in water under UV-illumination. The prepared sample has been characterized by powder X-ray diffraction (XRD), infrared spectroscopy (IR) and scanning electron microscopy (SEM). The supported catalyst had large surface area and good sedimentation ability. The photodegradation rate of β-naphthol under UV-irradiation depended strongly on adsorption capacity of the catalyst, and the photoactivity of the supported catalyst was much higher than that of the pure titanium dioxides. The experiments were measured by high performance liquid chromatography (HPLC). The photodegradation rate of β-naphthol using 60% TiO₂-SiO₂ particles was faster than that using TiO₂ 'Degussa P-25', TiO₂ 'PC-50' and TiO₂ 'Aldrich' as photocatalyst by 2.7, 4 and 7.8 times, respectively. The kinetics of photocatalytic β-naphthol degradation was found to follow a pseudo-first-order rate law. The effect of the TiO₂ loading on the photoactivity of TiO₂-SiO₂ particles was also discussed. With good photocatalytic activity under UV-irradiation and the ability to be readily separated from the reaction system, this novel kind of catalyst exhibited the potential effective in the treatment of organic pollutants in aqueous systems.