title: Environmental exposure to TiO2nanomaterials incorporated in building material.
abstract: Nanomaterials are increasingly being used to improve the properties and functions of common building materials. A new type of self-cleaning cement incorporating TiO2nanomaterials (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/m2of 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.
authors.affiliation: Aix Marseille Univ, CNRS, IRD, Coll France, CEREGE, Aix-en-Provence, France; INERIS (Unités NOVA), 60550 Verneuil-en-Halatte, France; ICEINT, CNRS, Duke Univ. International Consortium for the Environmental Implications of Nanotechnology, Aix-en-Provence, France.
authors.forename: Nathan
authors.initials: N
authors.lastname: Bossa
authors.affiliation: Aix Marseille Univ, CNRS, IRD, Coll France, CEREGE, Aix-en-Provence, France; ICEINT, CNRS, Duke Univ. International Consortium for the Environmental Implications of Nanotechnology, Aix-en-Provence, France.
authors.forename: Perrine
authors.initials: P
authors.lastname: Chaurand
authors.affiliation: Aix Marseille Univ, CNRS, IRD, Coll France, CEREGE, Aix-en-Provence, France; ICEINT, CNRS, Duke Univ. International Consortium for the Environmental Implications of Nanotechnology, Aix-en-Provence, France.
authors.forename: Clément
authors.initials: C
authors.lastname: Levard
authors.affiliation: Aix Marseille Univ, CNRS, IRD, Coll France, CEREGE, Aix-en-Provence, France; ICEINT, CNRS, Duke Univ. International Consortium for the Environmental Implications of Nanotechnology, Aix-en-Provence, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Borschneck
authors.affiliation: Aix Marseille Univ, CNRS, IRD, Coll France, CEREGE, Aix-en-Provence, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Miche
authors.affiliation: Aix-Marseille University, CNRS, IUSTI UMR 7343, 13013 Marseille, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Vicente
authors.affiliation: IRCELYON UMR5256 CNRS, University Lyon 1, 69626 Villeurbanne, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Geantet
authors.affiliation: INERIS (Unités NOVA), 60550 Verneuil-en-Halatte, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Aguerre-Chariol
authors.affiliation: Department of Geosciences, Virginia Tech, Blacksburg, Virginia 24060, USA; Center for Environmental Implications of NanoTechnology (CEINT), USA.
authors.forename: F Marc
authors.initials: FM
authors.lastname: Michel
authors.affiliation: Aix Marseille Univ, CNRS, IRD, Coll France, CEREGE, Aix-en-Provence, France; ICEINT, CNRS, Duke Univ. International Consortium for the Environmental Implications of Nanotechnology, Aix-en-Provence, France. Electronic address: rose@cerege.fr.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Rose
mesh_terms: D003252:Construction Materials / Q000032:analysis*; D004781:Environmental Exposure / Q000032:analysis*; D004785:Environmental Pollutants / Q000032:analysis* / Q000737:chemistry*; D007220:Industrial Waste / Q000032:analysis; D049329:Nanostructures / Q000032:analysis* / Q000737:chemistry*; D016062:Porosity; D045483:Rivers / Q000737:chemistry; D014025:Titanium / Q000032:analysis* / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry
chemical_list: D004785:Environmental Pollutants; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D014025:Titanium
keywords: Aging; Degradation rate; Lab-scale leaching; Life cycle; Photocatalytic cement; Release kinetics