Browsing by Author "Nunes, J."
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- Energy transition process and community engagement on geographic islands: the case of Culatra Island (Ria Formosa, Portugal)Publication . Pacheco, André; Monteiro, Jânio; Santos, Joni; Sequeira, Claudia; Nunes, J.Islands have the potential to be precursors in the transition to clean energy, by adopting new technologies and applying innovative solutions that can serve as showcases at an international level. This paper is a contribution towards understating the importance of community engagement on energy transition processes. It covers multiple aspects of a green transition process, including technical, environmental, social, and economic issues. Starting by a participatory diagnosis process, the community of a small island located in Portugal (Culatra Island, Algarve), was challenged to lead the transition process and define different pillars of energy transition. The process brought together local authorities, academia, citizens and companies. Using practical examples, it is shown how the community is succeeding in tailoring new technological solutions for a green transition, according with the specific needs of the island, as expressed by the islanders themselves, including batteries, electric vehicles, retrofitting of homes, or heat pumps, which, when combined, could lay the foundations for the creation of a Renewable Energy Community and leverage socioeconomic benefits.
- Evaluation of eutrophication in the Ria Formosa coastal lagoon, PortugalPublication . Newton, Alice; Icely, John; Falcão, Manuela; Nobre, A.; Nunes, J.; Ferreira, J.; Vale, C.The Ria Formosa is a shallow mesotidal lagoon on the south coast of Portugal, with natural biogeochemical cycles essentially regulated by tidal exchanges at the seawater boundaries and at the sediment interface. Existing data on nutrients in the water column and the sediment, together with chlorophyll a and oxygen saturation in the water column,compared using different models for assessing eutrophication. The European Environmental Agency criteria are based on the comparison of nutrient concentrations which indicate that the situation in the Ria Formosa is ‘‘poor’’ to ‘‘bad’’. In contrast, the United States Estuarine Eutrophication Assessment is based on symptoms, including high chlorophyll a and low oxygen saturation, which indicate that the Ria Formosa is near pristine. Despite these contradictions, a preliminary assessment by Driving forces, Pressures, State, Impact, Reponses(DPSIR) of eutrophication demonstrate the potential for episodic eutrophic conditions from treated and untreated domestic effluent as well as from non-point source agricultural run off. Sediments are also an important source of nutrients in the lagoon, but their contribution to potential eutrophic conditions is unknown.
- Photodegradation of chloramphenicol and paracetamol using PbS/TiO2 nanocomposites produced by green synthesisPublication . Palma, Tânia Cristina da Luz; Vieira, Bernardete; Nunes, J.; Lourenço, J. P.; Monteiro, O. C.; Costa, Maria ClaraThe present study describes the photocatalytic potential of the successfully synthesized nanocrystalline PbS/TiO2 nanocomposites in the photodegradation of chloramphenicol and paracetamol. PbS and PbS/TiO2 nanoparticles were synthesized using biological sulphide produced by sulphate-reducing bacteria in batch and in a coupled bioremediation system (upflow anaerobic packed-bed reactor) for acid mine drainage treatment, yielding near-complete metal precipitation (~ 100–99%, respectively). The PbS and PbS/TiO2 composites obtained using sulphide generated in batch have an average particle size ranging from 17 to 25 nm and 15 to 20 nm, respectively, while in bioreactor, both PbS and PbS/TiO2 particles have a similar size range from 20 to 50 nm. All the produced particles presented crystalline cubic structure. The specific surface area of TiO2 and PbS/TiO2 was estimated to be 46.559 m2/g and 38.005 m2/g, respectively. Chloramphenicol removal by photolysis was about 61% after 60 min of Hg irradiation and 36% under sunlight exposition. Chloramphenicol photodegradation using PbS/TiO2 as catalyst was successfully performed in a photoreactor (Hg medium pressure, 450 W) and under solar exposition with a high drug removal efficiency of 96% and 93% after 60 min and 240 min irradiation, respectively. Using TiO2 as a catalyst for photodegradation achieved 98% removal for both Hg and sunlight irradiation (UV index ranging 7–8) after 60 min and 240 min, respectively. Paracetamol removal by photolysis was about 18%. Drug’s photocatalytic degradation using PbS/TiO2 was successfully performed under sunlight exposition with a high removal efficiency of 93%, while in the presence of TiO2, the removal was complete, after 235 min irradiation.