Aging of TiO2 nanocomposites used in sunscreen. Dispersion and fate of the degradation products in aqueous environment Article

Labille, J, Feng, J, Botta, C et al. (2010). Aging of TiO2 nanocomposites used in sunscreen. Dispersion and fate of the degradation products in aqueous environment . ENVIRONMENTAL POLLUTION, 158(12), 3482-3489. 10.1016/j.envpol.2010.02.012

cited authors

  • Labille, J; Feng, J; Botta, C; Borschneck, D; Sammut, M; Cabie, M; Auffan, M; Rose, J; Bottero, JY

authors

abstract

  • Aging in water of a TiO2-based nanocomposite used in sunscreen cosmetics has been studied as a function of light and time. It consisted initially in a TiO2 core, coated with Al(OH)3 and polydimethylsiloxane (PDMS) layers. Size measurement, coating alteration, and surface charge were followed by laser diffraction, TEM/EDS, ICP-AES and electrophoretic mobility measurement. The nanocomposite rapidly underwent progressive dispersion in the aqueous phase, enabled by the dissolution of the PDMS layer. A stable suspension of colloidal byproducts from 50 to 700 nm in size was formed. Their positively charged Al(OH)3 surface was evidenced with an isoelectric point around 7-8, controlling the dispersion stability. The critical coagulation concentrations measured with NaCl and CaCl2 was 2 × 10-2 and 8 × 10-3 M respectively. The presence of natural organic matter affected the colloidal stability according to the NOM/byproduct ratio. A 2 wt% ratio favored bridging flocculation, whereas a 20 wt% ratio induced sterical stabilization. © 2010 Published by Elsevier Ltd. All rights reserved.

publication date

  • December 1, 2010

published in

Digital Object Identifier (DOI)

start page

  • 3482

end page

  • 3489

volume

  • 158

issue

  • 12