Environmental exposure to TiO2 nanomaterials incorporated in building material - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Environmental Pollution Année : 2017

Environmental exposure to TiO2 nanomaterials incorporated in building material

F. Marc Michel
  • Fonction : Auteur

Résumé

Abstract Nanomaterials are increasingly being used to improve the properties and functions of common building materials. A new type of self-cleaning cement incorporating TiO2 nanomaterials (TiO2-NMs) with photocatalytic properties is now marketed. This promising cement might provide air pollution-reducing properties but its environmental impact must be validated. During cement use and aging, an altered surface layer is formed that exhibits increased porosity. The surface layer thickness alteration and porosity increase with the cement degradation rate. The hardened cement paste leaching behavior has been fully documented, but the fate of incorporated TiO2-NMs and their state during/after potential release is currently unknown. In this study, photocatalytic cement pastes with increasing initial porosity were leached at a lab-scale to produce a range of degradation rates concerning the altered layer porosity and thickness. No dissolved Ti was released during leaching, only particulate TiO2-NM release was detected. The extent of release from this batch test simulating accelerated worst-case scenario was limited and ranged from 18.7 ± 2.1 to 33.5 ± 5.1 mg of Ti/m2 of cement after 168 h of leaching. TiO2-NMs released into neutral aquatic media (simulate pH of surface water) were not associated or coated by cement minerals. The TiO2-NM release mechanism is suspected to start from freeing of TiO2-NMs in the altered layer pore network due to partial cement paste dissolution followed by diffusion into the bulk pore solution to the surface. The extent of TiO2-NM release was not solely related to the cement degradation rate.

Mots clés

Dates et versions

hal-01426082 , version 1 (04-01-2017)

Identifiants

Citer

Nathan Bossa, Perrine Chaurand, Clément Levard, Daniel Borschneck, Helene Miche, et al.. Environmental exposure to TiO2 nanomaterials incorporated in building material. Environmental Pollution, 2017, 220, Part B, pp.1160 - 1170. ⟨10.1016/j.envpol.2016.11.019⟩. ⟨hal-01426082⟩
324 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More