Concurrent Aggregation and Deposition of TiO2 Nanoparticles in a Sandy Porous Media

• Published in: Environmental science & technology Vol. 44; no. 13; pp. 4897 - 4902
• Main Authors: Solovitch, Natalia, Labille, Jérôme, Rose, Jérôme, Chaurand, Perrine, Borschneck, Daniel, Wiesner, Mark R, Bottero, Jean-Yves
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.07.2010
• Subjects: Applied sciences; Characterization of Natural and Affected Environments; Environmental Monitoring - methods; Environmental Sciences; Exact sciences and technology; Hydrogen-Ion Concentration; Kinetics; Metal Nanoparticles - chemistry; Nanotechnology - methods; Particle Size; Pollution; Porosity; Silicon Dioxide; Surface Properties; Time Factors; Titanium - chemistry; Transport process; Nanoparticle; Porous medium; Kinetics; Titanium oxide; Nanostructured materials; Catalyst; Porous pavement
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es1000819

The possibility of simultaneous particle aggregation and deposition in a porous medium was examined for the case of TiO2 nanoparticles (NPs). While potential for particle aggregation is typically assumed to be negligible in porous media due to favored interactions with porous media surfaces (collectors), we show that nanoscale particle dimensions may favor aggregation kinetics, thus altering the transport and retention of these materials in saturated porous media. When surface chemistry favors nanoparticle−nanoparticle attachment (αpp) over nanoparticle-collector attachment (αpc), the rate of particle aggregation within pores may be comparable to that of deposition at ratios of collector to nanoparticle surface areas as high as 40. Aggregation of NPs in the porous media enhances NP deposition, however aggregates that are not removed will sample a smaller portion of the available pore network within the column due to size exclusion.