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Publications (2)2.01 Total impact

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    ABSTRACT: In this study we investigate the impact of input concentration on the mobility of poly(acrylic acid) supported magnetite nanoparticles in saturated porous media. Transport experiments were conducted in a water-saturated sand-packed column for nanoparticle suspensions with total Fe concentrations ranging from 100 to 600 mg/L. Particle size analysis of the synthesized nanoparticle solutions showed that PAA provides good size stability for Fe concentrations as low as about 1 mg/L. Time-moment analysis of the nanoparticle breakthrough curves, on the other hand, revealed that nanoparticles mass recovery from the column decreased consistently with dilution, with greater attenuation, sharper fronts and longer tails compared to that of the tracer. To further interpret the experimental results, a nanoparticle transport model that accounts for deposition/detachment kinetics was developed. The best agreement between the observed breakthrough curves and model simulations was obtained using a kinetic time-dependent deposition term with finite deposition capacity and a kinetic detachment term. The model results suggest that the decrease in mass recovery with decrease in input particle concentration may be due to time-dependent blocking that hinders further deposition. The implications of these results on the use of engineered nanoparticles for groundwater remediation applications are discussed.
    AGU Fall Meeting Abstracts. 12/2011;
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    ABSTRACT: This paper investigates the impact of dilution on the mobility of magnetite nanoparticles surface coated with poly(acrylic acid) (PAA). Transport experiments were conducted in a water-saturated sand-packed column for input nanoparticle solutions with total Fe concentrations ranging from 100 to 600mg/L. Particle size analysis of the synthesized nanoparticle solutions showed that PAA provides good size stability for Fe concentrations as low as about 1mg/L. Time-moment analysis of the nanoparticle breakthrough curves, on the other hand, revealed that nanoparticle mass recovery from the column decreased consistently with dilution, with greater attenuation, sharper fronts and longer tails compared to that of the tracer. Particle size analysis of the eluted solutions shows that the nanoparticle size is negatively correlated with nanoparticle concentration. Modeling results suggest that the decrease in nanoparticle mobility with input concentration can be represented using a kinetic time-dependent deposition term with finite deposition capacity and a kinetic detachment term. For field applications, the increase in particle size and detachment resulting from dilution means reduced transport efficiency of nanoparticles and reaction potential with travel distance.
    Journal of contaminant hydrology 11/2011; 126(3-4):248-57. · 2.01 Impact Factor