Transport of in Situ Mobilized Colloidal Particles in Packed Soil Columns

Abstract

A systematic investigation of the transport behavior of in situ mobilized soil colloidal particles in their parent soil matrix medium is presented. Particle advection, dispersion, and deposition kinetics were studied by analysis of particle breakthrough curves as a response to short-pulse particle injections to the inlet of packed soil columns. The transport of the heterogeneous soil particles was compared to the transport of monodisperse carboxyl latex particles to further understand the various particle transport mechanisms. Results show that colloidal particles travel much faster than a conservative tracer (nitrate) due to size exclusion effects, whereby mobile colloidal particles are excluded from small pores within the soil medium. Dispersivity of the natural and latex particles was compared to that of the conservative tracer, and the results indicate that particle dispersivity is greater than the tracer dispersivity. Dispersivity of colloidal particles was shown to be essentially independent of pore...