Browsing by Keyword "TiO nanoparticles"
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Item Aging of photocatalytic coatings under a water flow: Long run performance and TiO 2 nanoparticles release(2012-07-23) Olabarrieta, Josune; Zorita, Saioa; Peña, Iratxe; Rioja, Nerea; Monzón, Oihane; Benguria, Pablo; Scifo, Lorette; ADAPTACIÓN AL CAMBIO CLIMÁTICO; Mercado; MATERIALES PARA CONDICIONES EXTREMASAlthough photocatalytic coatings may experience severe wearing in most of their application, little work has been done to investigate their aging in a comprehensive way. In this article, we present an original experimental protocol to simulate an accelerated aging of photocatalytic coatings under a water flow, and test it on two materials: a well-known commercial product, Pilkington Activ™, and an experimental coating. The influence of intrinsic properties of the coatings (chemical nature, thickness) as well as environmental parameters (water matrix, UV-light) is investigated while the consequences of aging are evaluated under three different endpoints, related either to the long run performance of photocatalytic coatings or their environmental impact: (i) loss of the photocatalytic activity, (ii) degradation of mechanical properties, and (iii) release of TiO 2 nanoparticles. It is observed that both photocatalytic coatings experienced a deactivation of their active sites upon prolonged immersion. The extent of deactivation varies depending on the coating, being around 20% for experimental coatings and 65% for Pilkington Activ™ but shows little dependency on water matrix or illumination. An alteration of mechanical properties is seen on experimental coatings, which was accompanied by TiO 2 emissions as high as 150.5μgL -1. Although no reduction in film hardness or adhesion could be evidenced for Pilkington Activ™, TiO 2 concentrations up to 30.8μgL -1 was detected in the aging water showing that some release of TiO 2 nanoparticles also took place on this material. Interestingly, a common mechanism of release, triggered by an interaction between TiO 2, NaCl and UVA could be identified. Most severe damages were observed in presence of sodium chloride. These results suggest that the use of photocatalytic coatings with surface-bound nanoparticles in environmental applications may entail new entries of nanomaterials into the aqueous medium. They also prove that aging assays are an effective way of assessing the emissions.Item TiO2-Doped Electrospun Nanofibrous Membrane for Photocatalytic Water Treatment(2019-04-26) Blanco, Miren; Monteserín, Cristina; Angulo, Adrián; Pérez-Márquez, Ana; Maudes, Jon; Murillo, Nieves; Aranzabe, Estíbaliz; Ruiz-Rubio, Leire; Vilas, Jose Luis; Tecnalia Research & Innovation; PRINTEXThis work has been focused on the one-step fabrication by electrospinning of polyamide 6 (PA6) nanofibre membranes modified with titanium dioxide nanoparticles (TiO2), where these TiO2 nanoparticles aggregates could induce a photocatalytic activity. The main potential application of these membranes could be the purification of contaminated water. Thus, it is important to analyse the contaminant degradation capability since in these membranes this is based on their photocatalytic activity. In this work, the effect of the photocatalysis has been studied both on the degradation of an organic model contaminant and on the removal of Escherichia coli and other coliform bacteria. As a result, it was observed that these membranes present excellent photocatalytic activity when they are irradiated under UV light, allowing a 70% reduction of an organic model pollutant after 240 min. In addition, these membranes successfully removed Escherichia coli and other coliform bacteria in artificially inoculated water after 24 h of contact with them. Moreover, the stand-alone structure of the membranes allowed for the reusing of the immobilized catalyst. The experimental evidence indicated that developed nanofibre membranes are a fast and efficient solution for polluted water decontamination based on photocatalysis. Their use could contribute to guarantee a fresh water level and quality, mitigating the water scarcity problem worldwide.