Evaluation of the photocatalytic performance of construction materials for urban air depollution
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(2020) 5:25
ORIGINAL PAPER
Evaluation of the photocatalytic performance of construction materials for urban air depollution S. Suárez1 · M. D. Hernández‑Alonso2 · C. Martínez1 · B. Sanchez1 Received: 21 November 2019 / Accepted: 20 April 2020 © Springer Nature Switzerland AG 2020
Abstract The photocatalytic degradation of trichloroethylene and nitric oxide (model volatile organochloride and inorganic compounds) by two commercial T iO2-based cementitious materials at the laboratory scale was studied. T iO2 P25 was selected as the benchmark photocatalyst. The materials were characterized by N 2 adsorption–desorption, TGA, SEM–EDX, and XRD, and the hydrophobic/hydrophilic nature of the cement surface was determined through contact angle measurements. Preliminary photoactivity tests in which a glass plate was covered with photocatalytic material were performed. Moreover, the photocatalytic activities of asphalt plates (approximately 1 cm thick) covered with either of the photoactive cementitious materials were also evaluated. A notable improvement in the photocatalytic activity from the first to the second photocatalytic run was observed because sample conditioning with airflow and UV-A irradiation led to the elimination of species (carbonates) that were adsorbed at active T iO2 sites, ensuring stability under operating conditions. The cementitious samples completely photooxidized the organochloride compound but presented reduced photoefficiency for nitric oxide oxidation. The results obtained when the materials were deposited on glass and asphalt showed the crucial influences of the sample loading and the nature of the substrate on nitric oxide photooxidation. Using TiO2 P25 led to the complete conversion of nitric oxide but also to the formation of a large amount of nitrogen dioxide. On the other hand, one of the photoactive asphalts exhibited a nitric oxide conversion rate of 32%, which was lower than that achieved with pure T iO2-P25, but using this material did not lead to the release of nitrogen dioxide. When tested according to the ISO 22197-1:2007 standard, the selected photocatalytic asphalt removed 29% of the NO and 22% of the NOx under more demanding operating conditions. Keywords Cementitious materials · Photocatalysis · TiO2 · VOCs · Nitrogen oxides · Air pollution control · Photocatalytic asphalts
Introduction The use of photocatalytic cement and architectonic elements as passive decontamination units has received a great deal of attention in recent years (Boonen et al. 2015; Maggos et al. 2008; Yu et al. 2017). Building construction materials such as roofing membranes and external building surfaces Communicated by Sami Rtimi, Chief Editor. * S. Suárez [email protected] 1
Photocatalytic Treatment of Pollutants in Air, Renewable Energy Division, CIEMAT, Avda. Computense 40, Building 42, 28040 Madrid, Spain
Repsol Technology Lab, C/Agustín de Betancourt s/n, 28935 Madrid, Spain
2
(Baudys et al. 2015) as well as green city elements based on photocatalytic concrete (Hassan e
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