Deposition and release kinetics of nano-TiO2 in saturated porous media: Effects of solution ionic strength and surfactants

• Published in: Environmental pollution (1987) Vol. 174; pp. 106 - 113
• Main Authors: Godinez, Itzel G., Darnault, Christophe J.G., Khodadoust, Amid P., Bogdan, Dorin
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-03-2013; Elsevier
• Subjects: Accumulators; Applied sciences; Attachment; Benzenesulfonates - chemistry; Biological and physicochemical phenomena; Biological and physicochemical properties of pollutants. Interaction in the soil; Collectors; Deposition; Earth sciences; Earth, ocean, space; Electrolytes; energy; Engineering and environment geology. Geothermics; Exact sciences and technology; Ionic strength; Kinetics; Metal Nanoparticles - analysis; Metal Nanoparticles - chemistry; micelles; Models, Chemical; Nanoparticle; nanoparticles; Nanostructure; Natural water pollution; octoxynol; Octoxynol - chemistry; Osmolar Concentration; Particle Size; Pollution; Pollution, environment geology; Porosity; porous media; Release; Saturated porous media; sodium; Soil and sediments pollution; Strength; Surface-Active Agents - chemistry; Surfactant; Surfactants; Titanium - analysis; Titanium - chemistry; Titanium dioxide; Transport; Water treatment and pollution; Saturated porous media; Nanoparticle; Ionic strength; Surfactant; Transport; Titanium dioxide; Deposition; Release; Detergent; Non ionic surfactant; Porous medium; Environmental factor; Soil pollution; Sediments; Transport process; Anionic surfactant; Micellar critical concentration; Water pollution; Aggregate; Titanium oxide; Nanostructured materials; Nanotechnology; Organic compounds
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2012.11.002

The aggregation, transport and deposition kinetics (i.e. attachment and release) of TiO2 nanoparticles (nano-TiO2) were investigated as a function of ionic strength and the presence of anionic (sodium dodecylbenzene sulfonate, SDBS) and non-ionic (Triton X-100) surfactants in 100% critical micelle concentration (CMC). The electrolyte concentration of the suspensions dictated the kinetic stability of nano-TiO2 thus influencing the transport and retention of the nanoaggregates in the saturated porous medium. With increasing ionic strength, the interaction between approaching nano-TiO2 and nano-TiO2 already deposited onto collectors surfaces seemed to be more favorable than the interaction between approaching nano-TiO2 and bare collectors surfaces. The abrupt and gradual reduction in electrolyte concentration during the flushing cycles of the column experiments induced the release of previously deposited nano-TiO2 suggesting attachment of nano-TiO2 through secondary energy minimum.
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► This study focuses on aggregation, transport and deposition kinetics of nano-TiO2. ► Ionic strength and surfactants impact nano-TiO2 transport in saturated porous media. ► Previously deposited nano-TiO2 serve as preferential sites for subsequent deposition. ► Changes in solution chemistry cause nanodeposits to release a portion of nano-TiO2.
Previously deposited nano-TiO2 serve as preferential sites for subsequent deposition and changes in solution chemistry cause nanodeposits to release a portion of nano-TiO2.