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The Fate and Transport of the SiO2 Nanoparticles in a Granular Activated Carbon Bed and Their Impact on the Removal of VOCs
Salih, H. H., C. L. PATTERSON, G. A. Sorial, R. Sinha, AND R. Krishnan. The Fate and Transport of the SiO2 Nanoparticles in a Granular Activated Carbon Bed and Their Impact on the Removal of VOCs. JOURNAL OF HAZARDOUS MATERIALS. Elsevier Science Ltd, New York, NY, 193:95-101, (2011).
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Adsorption isotherm, adsorption kinetics and column breakthrough experiments evaluating trichloroethylene (TCE) adsorption onto granular activated carbon (GAC) were conducted in the presence and absence of silica nanoparticles (SiO2 NPs). Zeta potential of the SiO2 NPs and the GAC were measured. Particle size distribution (PSD) of the SiO2 NPs dispersions was analyzed as a function of time to evaluate the extent of aggregation. TEM analysis were conducted. The specific surface area and the pore size distribution of the virgin and the spent GAC were obtained. The fate and transport of the SiO2 NPs in the GAC fixed bed and their impact on TCE adsorption were found to be a function of their zeta potential, concentration, PSD. The interaction of the SiO2 NPs and the GAC is of an electrokinetic nature. A weak electrostatic attraction was observed between the SiO2 NPs and the GAC. This attraction favors SiO2 NPs attachment on the surface of GAC. SIO2 NPs attachment onto GAC is manifested by a reduction in the amount of TCE adsorbed during the column breakthrough experiments suggesting a preloading pore blockage phenomena. However, no effect of SiO2 NPs was observed on the isotherm and the kinetic studies, this is mainly due to the fast kinetics of TCE adsorption.