Browsing by Keyword "Activated carbon"
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Item Competitive removal of pharmaceuticals from environmental waters by adsorption and photocatalytic degradation(2014-08-01) Rioja, N.; Benguria, P.; Peñas, F. J.; Zorita, S.; MATERIALES PARA CONDICIONES EXTREMAS; ADAPTACIÓN AL CAMBIO CLIMÁTICOThis work explores the competitive removal of pharmaceuticals from synthetic and environmental waters by combined adsorption-photolysis treatment. Five drugs usually present in waterways have been used as target compounds, some are pseudo-persistent pollutants (carbamazepine, clofibric acid, and sulfamethoxazole) and others are largely consumed (diclofenac and ibuprofen). The effect of the light source on adsorption of drugs onto activated carbons followed by photolysis with TiO2 was assessed, being UV-C light the most effective for drug removal in both deionized water and river water. Different composites prepared from titania nanoparticles and powdered activated carbons were tested in several combined adsorption-photocatalysis assays. The composites prepared by calcination at 400 °C exhibited much better performance than those synthesized at 500 °C, being the C400 composite the most effective one. Furthermore, some synthetic waters containing dissolved species and environmental waters were used to investigate the effect of the aqueous matrix on each drug removal. In general, photocatalyst deactivation was found in synthetic and environmental waters. This was particularly evident in the experiments performed with bicarbonate ions as well as with wastewater effluent. In contrast, tests conducted in seawater showed adsorption and photocatalytic degradation yields comparable to those obtained in deionized water. Considering the peculiarities of substrate competition in each aqueous matrix, the combined adsorption-photolysis treatment generally increased the overall elimination of drugs in water.Item Synergy effect in the photocatalytic degradation of pharmaceuticals on a suspended mixture of titania and activated carbon(TANGER Ltd., 2012) Rioja, Nerea; Benguria, Pablo; Scifo, Lorette; Zorita, Saioa; MATERIALES PARA CONDICIONES EXTREMAS; ADAPTACIÓN AL CAMBIO CLIMÁTICOPhotocatalysis is currently being considered for many environmental applications such as water decontamination. This is due to its ability to degrade organic pollutants to CO2, water and mineral acids. In TiO2 photocatalysis, UV radiation is needed to create hole-electron pairs which can be transferred to water to form oxidizing species. However this process generally suffers low apparent quantum yield, mainly due to the rapid recombination of the photogenerated electron-holes. In order to improve quantum yields, the addition of activated carbon (AC) has been suggested. As adsorption is a key point in photocatalysis, the addition of AC can aid to increase pollutant's degradation kinetics by augmenting their adsorption onto the TiO2-AC interphase. Carbon has also been suggested to act as an electron sink which may retard the recombination of electron-hole pairs. The aim of our work is to study the synergistic effect of TiO2-AC on the removal of five different pharmaceuticals from water. Two different ACs were tested to identify the best working conditions. Different routes to combine TiO2-AC were as well studied. Experiments under the following conditions: UV+TiO2, UV+AC and UV+TiO2+AC were performed in order to determine % of removal by photocatalysis, adsorption and by the synergistic effect of TiO2-AC. Drugs degradation in a real matrix such as river water, and not only in ultrapure water, was also investigated.Item Synergy effect in the photocatalytic degradation of pharmaceuticals on a suspended mixture of titania and activated carbon(TANGER Ltd., 2010) Rioja, Nerea; Benguria, Pablo; Scifo, Lorette; Zorita, Saioa; MATERIALES PARA CONDICIONES EXTREMAS; ADAPTACIÓN AL CAMBIO CLIMÁTICOPhotocatalysis is currently being considered for many environmental applications such as water decontamination. This is due to its ability to degrade organic pollutants to CO2, water and mineral acids. In TiO2 photocatalysis, UV radiation is needed to create hole-electron pairs which can be transferred to water to form oxidizing species. However this process generally suffers low apparent quantum yield, mainly due to the rapid recombination of the photogenerated electron-holes. In order to improve quantum yields, the addition of activated carbon (AC) has been suggested. As adsorption is a key point in photocatalysis, the addition of AC can aid to increase pollutant's degradation kinetics by augmenting their adsorption onto the TiO2-AC interphase. Carbon has also been suggested to act as an electron sink which may retard the recombination of electron-hole pairs. The aim of our work is to study the synergistic effect of TiO2-AC on the removal of five different pharmaceuticals from water. Two different ACs were tested to identify the best working conditions. Different routes to combine TiO2-AC were as well studied. Experiments under the following conditions: UV+TiO2, UV+AC and UV+TiO2+AC were performed in order to determine % of removal by photocatalysis, adsorption and by the synergistic effect of TiO2-AC. Drugs degradation in a real matrix such as river water, and not only in ultrapure water, was also investigated.