Transport of in Situ Mobilized Colloidal Particles in Packed Soil Columns

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• 作者：Daniel Grolimund ; Menachem Elimelech ; Michal Borkovec ; Kurt Barmettler ; Ruben Kretzschmar ; and Hans Sticher
• 刊名：Environmental Science & Technology
• 出版年：1998
• 出版时间：November 15, 1998
• 年：1998
• 卷：32
• 期：22
• 页码：3562 - 3569
• 全文大小：120K
• 年卷期：v.32,no.22(November 15, 1998)
• ISSN：1520-5851

文摘

A systematic investigation of the transport behavior of insitu mobilized soil colloidal particles in their parent soil matrixmedium is presented. Particle advection, dispersion,and deposition kinetics were studied by analysis of particlebreakthrough curves as a response to short-pulseparticle injections to the inlet of packed soil columns.The transport of the heterogeneous soil particles wascompared to the transport of monodisperse carboxyl latexparticles to further understand the various particletransport mechanisms. Results show that colloidal particlestravel much faster than a conservative tracer (nitrate)due to size exclusion effects, whereby mobile colloidalparticles are excluded from small pores within the soilmedium. Dispersivity of the natural and latex particles wascompared to that of the conservative tracer, and theresults indicate that particle dispersivity is greater thanthe tracer dispersivity. Dispersivity of colloidal particles wasshown to be essentially independent of pore watervelocity, whereas tracer dispersivity increased withincreasing pore water velocity due to a combination ofconvective and diffusive transport of tracer molecules insmall pores within the soil aggregates. The effect of divalentcounterions on particle deposition kinetics was alsoinvestigated by comparing the results to deposition kineticswith monovalent counterions. Particle deposition ratewith Ca²⁺ was shown to be higher than with Na⁺, and thecritical deposition concentrations with Na⁺ were greaterthan those with Ca²⁺. In contrast to the marked effect ofionic strength and divalent cations, changes in protonactivity over more than 1 order of magnitude (from pH 4.0to 5.5) did not have a significant effect on particledeposition kinetics. Quantitative analysis of the observedparticle transport results demonstrates that the transportof the natural colloidal particles in the packed soil columnscan be adequately described by the advection-dispersionequation with a first-order, irreversible deposition kineticsterm.