High quality luminescent CdS nanocrystals (NCs), with band edge emission tunable in the blue region of the visible spectrum, were synthesized by means of thermal decomposition of precursors with oleic acid as the surfactant and incorporated in optically transparent polystyrene (PS) and poly(methyl methacrylate) (PMMA). The optical properties of the obtained nanocomposite films were investigated by absorption and emission spectroscopies. Enhancement of the band edge luminescence of CdS quantum dots was observed in both polymer matrices and the fluorescence of the composites retained narrow emission profiles. Capping exchange at the NC surface with octylamine, demonstrated to improve the luminescence properties in solution, was performed in order to investigate the role played by surface ligands in the nanocomposite. Octylamine capped NCs immobilized in the polymers showed high defect state emission and visible quenching of band edge luminescence, indicating an effective interaction between oleic acid and PMMA and PS polymeric chains.

Xenobiotic persistent organic pollutants are ubiquitous in the environment (air, water, soil, biota), and this is the origin of the rising concern about their potential impact. Recent advances in chemical analysis at trace levels and a lack of knowledge about the fate and transport of reference compounds lead to a strong research demand in this area. In this context, special attention is focused on control technologies in water and wastewater involving the application of advanced technologies to minimize their environmental release. After presenting the environmental and sanitary impacts associated with the main classes of persistent xenobiotic compounds, this article focuses on endocrine-disrupting compounds (EDCs), a class of chemicals interfering with the endocrine systems of mammals and lower animals. In the second part of this article, the basic principles of the advanced technologies used for EDC control in water and wastewater are critically discussed with specific reference to their engineering aspects.

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An extensive optical and photoelectrochemical study of blended systems composed of organic-capped TiO(2) nanocrystals with either a spherical or rodlike morphology and a conjugated polymer, MEH-PPV, is presented. The absorption and emission properties of the heterojunctions have been characterized both in solution and in thin films. The blended structures deposited onto conductive substrates have been employed as active layers in photoelectrochemical systems. The investigation has been focused on the photoinduced charge transfer and recombination processes at the interface between the two components, as a function of the nanocrystal shape and surface coating, and of the film thickness. The presence of a large number of interfaces available for charge transfer is believed to play a fundamental role in enhancing the photoelectrochemical performances of the dispersed heterojunctions. The reported results suggest that such MEH-PPV/TiO(2) heterojunctions may be exploited as potential active layers in future photovoltaic and photoelectrochemical devices.

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