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

Godinez, Itzel G.; Darnault, Christophe J.G.; Khodadoust, Amid P.; Bogdan, Dorin

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

2013

Godinez, Itzel G. | Darnault, Christophe J.G. | Khodadoust, Amid P. | Bogdan, Dorin

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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