Abstract
The ability of photocatalytic cementitious materials to degrade nitrogen oxides (NOx) has been widely used to evaluate their air-purifying function. However, attention has been predominantly placed on the changes in the NOx concentration but the fate of the degradation products is seldom investigated. This study presents a preliminary laboratory investigation on the photocatalytic NOx degradation of nano titanium dioxide (TiO2) incorporated self-compacting glass mortar (SCGM). Focus was mainly placed on the generation and distribution of the degradation products, nitrite (NO2 −) and nitrate (NO3 −), during the NOx removal process. The results showed that the photocatalytic SCGM induced an apparent decrease of NO together with a slight increase of NO2 under UVA irradiation. Meanwhile, the amount of the generated NO2 − and NO3 − on the surface of the tested samples, in the suspended aerosols, and in the flowing air stream increased as the photocatalytic reaction progressed. The accumulation of NO2 − and NO3 − on the sample surface led to a slight deactivation effect on the photocatalytic NOx removal ability of the SCGM, which, in turn, slowed down the production of NO2 − and NO3 −. Interestingly, compared with NO3 −, NO2 − could more easily be carried away from the sample surface by the flowing air stream. On-site monitoring of the photocatalytic NOx removal activity of the paving blocks produced with the incorporation of TiO2 on the surface layer (Eco-block) confirmed the build-up of NO2 − and NO3 − with time, which well demonstrated the NOx removal ability of the photocatalytic blocks in real site applications.
Original language | English |
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Pages (from-to) | 412-418 |
Number of pages | 7 |
Journal | Building and Environment |
Volume | 144 |
DOIs | |
Publication status | Published - 15 Oct 2018 |
Keywords
- Air-purifying
- Nitrite and nitrate accumulation
- Photocatalytic NO removal
- Recycled glass
- TiO
ASJC Scopus subject areas
- Environmental Engineering
- Civil and Structural Engineering
- Geography, Planning and Development
- Building and Construction