Photocatalytic activity of titanium citrate and its water-in-oil microemulsions mix with zinc (II) tetraphenylporphyrin have been studied by means of adding 4-chlorophenol and following its degradation using artificial ultraviolet and visible light. 4-Chlorophenol is degraded in 71 and 86%, respectively, in 30 min with the generation of various intermediaries, whose possible formation mechanisms have been proposed based in the results of this research. The generation of benzene derivatives, different to those usually reported for this type of treatment, suggests the possibility of controlling the generation of intermediaries by simply changing the type of surfactant. In the case discussed here, we have derived a simple method for isomer generation of trimethylbenzene using a model organohalogenated compound as water contaminant and cetyltrimethylammonium bromide as surfactant.

The electrochemical oxidation of lambdacyhalotrin in a triton X-100 water solution on a PbO2-Bi electrode has been studied. It was discovered that electrocatalytic degradation proceeded through the Langmuir-Hinshelwood (L-H) mechanism. The Langmuir adsorption equilibrium constant of the organic compound on the PbO2-Bi surface (0.67 (±0.02) mg-1L) and the L-H maximum reaction rate for lambdacyhalotrin oxidation (0.040 (±0.002) mg L-1 min-1) was also determined on the basis of kinetic data. Oxidation/mineralization was tested at electrode potential higher than 2.3 V vs. Ag/AgCl, in this conditions the higher degradation percent of 85 (±4) % has been obtained.

In this study, photoelectrochemical solar cells based on bismuth tungstate electrodes were evaluated. Bi2WO6 was synthesized by a hydrothermal method and characterized by scanning electron microscopy, UV-Vis reflectance spectroscopy, and X-ray powder diffraction. For comparison, solar cells based on TiO2 semiconductor electrodes were evaluated. Photoelectrochemical response of Grätzel-type solar cells based on these semiconductors and their corresponding sensitization with two inexpensive phthalocyanines dyes were determined. Bi2WO6-based solar cells presented higher values of photocurrent and efficiency than those obtained with TiO2 electrodes, even without sensitization. These results portray solar cells based on Bi2WO6 as promising devices for solar energy conversion owing to lower cost of production and ease of acquisition.

Hydrodemetallization of water soluble phthalocyanine belonging to the family of dyes used in the textile industry, nickel (II) phthalocyanine tetrasulfonic acid, was performed using microwave radiation in the presence of NiMo/Al2O3 and CoMo/Al2O3 catalysts. The results were 98 and 97 % for each catalyst, respectively, by a treatment time of 10 minutes, achieving the retention of an amount of metal in the catalyst and also the conversion of the phthalocyanine to N, N-dimethyl octanamine, which has surfactant and antiseptic properties.

Se realizó la hidrodesmetalización de una ftalocianina soluble en agua perteneciente a la familia de colorantes empleados en las industrias textileras, ftalocianina tetrasulfónica ácida de níquel (II), utilizando radiación microondas en presencia de los catalizadores NiMo/Al2O3 y CoMo/Al2O3. Los resultados obtenidos fueron de 98 y 97 % para cada catalizador respectivamente, en un tiempo de tratamiento de 10 minutos, logrando retener una cantidad del metal en el catalizador y también la conversión de la ftalocianina a N,N-dimetil octanamina, compuesto con propiedades surfactantes y antisépticas.