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We present recent results on solid-state dye-sensitized solar cell research using a polymer electrolyte based on a poly(ethylene oxide) derivative. The stability and performance of the devices have been improved by a modification in the method of assembly of the cells and by the addition of plasticizers in the electrolyte. After 30 days of solar irradiation (100 mW cm-2) no changes in the cell's efficiency were observed using this new method. The effect of the active area size on cell performance and the first results obtained for the first solar module composed of 4.5 cm2solid-state solar cells are also presented.

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High quantities of industrial wastewaters containing a wide range of organic and inorganic pollutants are being directly discharged into the environment, sometimes without proper treatment. Nanotechnology has a tremendous potential improving the existing treatments or even develop new treatment solutions. In this study, nano-TiO or nano-FeO was used for the photocatalytic treatment of kraft pulp mill effluent and mining effluent. The experiments with the organic effluent lead to reduction percentages of 93.3%, 68.4% and 89.8%, for colour, aromatic compounds and chemical oxygen demand, respectively, when treated with nano-TiO/HO/UV and nano-FeO/HO/UV, at pH 3.0. Significant removal of metals from the mining effluent was recorded but only for Zn, Al and Cd, the highest removal attained with 1.0 g L of nano-TiO/UV and nano-FeO/UV. Regarding the toxicity of the organic effluent to Vibrio fischeri, it was reduced with the treatments combining the oxidant and the catalyst. However, for the inorganic effluent, the best reduction was achieved using 1.0 g L of catalyst. In fact, the increase in dose of the catalyst, especially for nano-TiO, enhanced toxicity reduction. Our results have shown that the use of these NMs seemed to be more effective in the organic effluent than in metal-rich effluent.

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The rapid development of nanotechnology and the increasing use of nanomaterials (NMs) raise concern about their fate and potential effects in the environment, especially for those that could be used for remediation purposes and that will be intentionally released to the environment. Despite the remarkable emerging literature addressing the biological effects of NMs to aquatic organisms, the existing information is still scarce and contradictory. Therefore, aimed at selecting NMs for the treatment of organic and inorganic effluents, we assessed the potential toxicity of NiO (100 and 10-20 nm), Fe2O3 (≈85 × 425 nm), and TiO2 (<25 nm), to a battery of aquatic organisms: Vibrio fischeri, Raphidocelis subcapitata, Lemna minor, Daphnia magna, Brachionus plicatilis, and Artemia salina. Also a mutagenic test was performed with two Salmonella typhimurium strains. Suspensions of each NM, prepared with the different test media, were characterized by dynamic light scattering (DLS) and eletrophoretic light scattering (ELS). For the assays with marine species, no toxicity was observed for all the compounds. In opposite, statistically significant effects were produced on all freshwater species, being D. magna the most sensitive organism. Based on the results of this study, the tested NMs can be classified in a decreasing order of toxicity NiO (100 nm) > NiO (10-20 nm) > TiO2 (<25 nm) > Fe2O3, allowing to infer that apparently Fe2O3 NMs seems to be the one with less risks for receiving aquatic systems.

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