Joana Ângelo
University of Porto
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Featured researches published by Joana Ângelo.
Journal of Environmental Management | 2013
Joana Ângelo; Luísa Andrade; Luis M. Madeira; Adélio Mendes
This review provides a short introduction to photocatalysis technology in terms of the present environmental remediation paradigm and, in particular, NOx photoabatement. The fundamentals of photoelectrochemical devices and the photocatalysis phenomena are reviewed, highlighting the main reaction mechanisms. The critical historical developments on heterogeneous photocatalysis are briefly discussed, giving particular emphasis to the pioneer works in this field. The third part of this work focus mainly on NOx removal technology considering topics such as: TiO2 photochemistry; effect of the operating conditions on the photocatalysis process; Langmuir-Hinshelwood modeling; TiO2 photocatalytic immobilization approaches; and their applications. The last section of the paper presents the main conclusions and perspectives on the opportunities related to this technology.
Journal of Environmental Management | 2011
C. Águia; Joana Ângelo; Luis M. Madeira; Adélio Mendes
The present work aims to evaluate the photocatalytic activity of photo-TiO(2) from various producers (Evonik, Kemira, Kronos, Millennium, Sachtleben and Tayca), in the form of powder pressed films and upon incorporation in a water-based paint, for outdoor NO abatement. The photocatalytic activity of the different samples was evaluated in terms of NO conversion and selectivity towards nitrite and nitrate ions following approximately the ISO 22197-1:2007(E) standard. The highest yields obtained for powder pressed films were achieved with VLP7000 (0.70), followed by VLP7101 (0.55) and UVLP7500 (0.55), all from Kronos. On the other hand, when incorporated in paint films, the highest yields were obtained with PC500 and PC105 from Millennium and UV100 from Sachtleben (ca. 0.15). The paint matrix plays an important role on the photocatalytic activity. In particular, the time for steady state is one or two orders of magnitude higher when the photocatalysts are incorporated in paint films in relation to the powder pressed films. The paint films were activated following the procedure recommended by the above-mentioned standard. However, the photocatalytic activity of films incorporating P25 (Evonik) was displayed only when higher power radiation and higher humidity conditions were used. This allowed for similar levels of photocatalytic activity as the other paint films.
Environmental Pollution | 2018
Joana Ângelo; Pedro Magalhães; Luísa Andrade; Luis M. Madeira; Adélio Mendes
Photocatalysis was recognised as a suitable process for the photoabatement of atmospheric pollutants. The photooxidation mechanism on TiO2 has been widely studied. However, recent studies demonstrated that the very often-assumed photooxidation intermediated by the hydroxyl radical cannot explain all the experimental observations. Indeed, this study contributes for a new understanding of NO photooxidation. First, the adsorption equilibrium isotherms of NO, NO2 and H2O on the photocatalyst, Aeroxide® P25 from Evonik Industries, were obtained. Also, the concentration of hydroxyl radicals was determined by photoluminescence. A comprehensive design of experiments was then followed; NO conversion and selectivity were obtained as a function of the relative humidity, irradiance, NO inlet concentration and residence time, following a response surface methodology (RSM). These results were then used to discuss the photooxidation mechanism of NO.
Applied Catalysis B-environmental | 2016
Natércia C.T. Martins; Joana Ângelo; Ana V. Girão; Tito Trindade; Luísa Andrade; Adélio Mendes
Catalysis Today | 2010
C. Águia; Joana Ângelo; Luis M. Madeira; Adélio Mendes
Applied Catalysis A-general | 2014
Joana Ângelo; Luísa Andrade; Adélio Mendes
Applied Catalysis B-environmental | 2014
Ricardo Monteiro; Filipe V. S. Lopes; Adrián M.T. Silva; Joana Ângelo; Gabriela V. Silva; Adélio Mendes; Rui A.R. Boaventura; Vítor J.P. Vilar
Applied Surface Science | 2016
Joana Ângelo; Pedro Magalhães; Luísa Andrade; Adélio Mendes
Polymer Degradation and Stability | 2011
C. Águia; Joana Ângelo; Luis M. Madeira; Adélio Mendes
Aiche Journal | 2016
Natan Padoin; Luísa Andrade; Joana Ângelo; Adélio Mendes; Regina de Fátima Peralta Muniz Moreira; Cíntia Soares