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An aerosol-based process was used to prepare mesoporous TiO(2) microspheres (MTM) with an average diameter in the range of 0.5-1 microm. The structural characteristics and photocatalytic properties of the synthesized materials were determined. As-prepared MTM materials and those heated in air from 400 to 600 degrees C exhibited mesoporous texture with a narrow size distribution and an inorganic framework that consisted of 4-13 nm anatase crystallites. Pore volumes for the MTM materials were in the range of 0.17-0.34 cm(3) g(-1). Microspheres heated to 400 degrees C presented a locally ordered mesopore structure and possessed X-ray diffraction d spacings between 9.8 and 17.3 nm. Heating above 400 degrees C resulted in a loss of the mesoscopic order, a decrease of the surface area, retention of the porosity, and an increase of the anatase nanoparticle size to 13 nm. The accessibility of the pore volume was measured by monitoring the uptake of gallic acid (GA) using Fourier transform IR. The MTM materials made excellent catalysts for the photodegradation of GA, with the performance being higher than that of an equivalent sample of Degussa P25. The present MTM materials are advantageous in terms of their ease of separation from the aqueous phase, and hence a novel photocatalytic process is proposed based on separate adsorption and photocatalytic decomposition steps with an improved and more rational use of both catalyst and sunlight.

Se presentan los primeros resultados del análisis fisicoquímico de mezclas pigmentarias rojas y blancas empleadas en la decoración de cerámicas arqueológicas provenientes de sitios localizados en la cuenca media y baja del río Paraná (provincia de Entre Ríos, nordeste de Argentina). El material analizado corresponde a conjuntos cerámicos asociados a grupos Goya-Malabrigo, cronológicamente situados al final del Holoceno Tardío. Se utiliza la técnica MEB-EDX a fin de aportar datos relativos a la caracterización elemental de las pinturas, en su fracción inorgánica. La información obtenida señala altas concentraciones de Fe en las pinturas rojas, en tanto que aquellas blancas muestran cierta variabilidad en su composición, destacándose niveles elevados de Ca y P. Estos resultados constituyen un punto de partida para discutir las elecciones tecnológicas de estos grupos en relación con las preparaciones pigmentarias.Palabras clave: mezclas pigmentarias, análisis MEB-EDX, cerámica Goya-Malabrigo, cuenca del río Paraná, Holoceno Tardío This paper presents the initial results of the physical-chemical analysis of red and white pigment mixtures used to decorate archaeological ceramics found at sites in the middle and lower Paraná River basin (Entre Ríos province, Northeast Argentina