CLOGGING OF MODEL PORES WITH BROWNIAN PARTICLES

International audiencePore clogging with Brownian particles is of wide interest in filtration processes. We perform experiments where model sub-micrometric pores are clogged using a Brownian suspension. We study the influence of the ionic strength on the clog formation dynamics. The erosion/drag force competition is also studied using a crossflow in the inlet channel. The way the clogs disintegrate after the clogging process provides some information about their structure, which can be composed of two or three " layers " – labile or not. INTRODUCTION This paper reports new results about model pores clogging with strongly Brownian particles. The accumulation of particles in a porous media is a complex process which involves DLVO, steric and hydrodynamic interactions. The clogging phenomenon may occur in inkjet printers or numerous other applications such as water filtration through a membrane. While the fouling of a membrane at the macroscopic scale is well understood, the investigations at the pore scale are still at their beginning [1]. Very recent works have used model microchannels to study the effect of different parameters, such as ionic strength or Péclet number (advection/diffusion competition) on the clogging of pores at the micrometer scale [2-4]. The sub-micron dimensions are still unexplored in spite of strong specificities (Brownian motion, system size comparable to scales of interaction), and relevance (0.2 µm being a typical industrial pore size). In this context, we study the clogging/unclogging of silicon-glass channels with Brownian particles. We focus particularly on the influence of ionic strength and the building/erosion processes using a crossflow imposed in the inlet microchannel