Dynamics of pore fouling by colloidal particles at the particle level

Abstract

Particle filtration occurs whenever particles flow through porous media such as membrane. Progressive capture or deposition of particles inside porous structure often leads to complete, and generally unwanted, fouling of the pores. Previously there has been no experimental work that has determined the particle dynamics of such a process at the pore level, since imaging the particles individually within the pores remains a challenge. Here, we overcome this issue by flowing fluorescently dyed particles through a model membrane, a microfluidic filter, imaged by a confocal microscope. This setup allows us to determine the temporal evolution of pore fouling at the particle level, from the first captured particle up to complete blocking of the pore. We show that from the very beginning of pore fouling the immobile particles inside the pore significantly participate in the capture of other flowing particles. For the first time it is determined how particles deposit inside the pore and form aggregates that eventually merge and block the pore.

Membrane Surface Patterning as a Fouling Mitigation Strategy in Liquid Filtration: A Review

“…Besides the hydrodynamic effect, surface patterning affects the foulant by preventing deposition of particles on the valleys if the particle size is bigger than the valley size or by altering the particle crystallization entropy when the size is about similar. Membrane surface patterning induces turbulence via local mixing near the membrane surface, requiring lower linear velocity and thus lowering the pressure loss along the module [7,41,42,43,44,45]. This advantage makes membrane surface patterning gain more attention of researchers to explore all its possible application opportunities.…”

“…Membrane–mold adhesion during demolding affects the structure and the smoothness of the membrane surface which hinders its wide application in liquid separation processes due to the presence of a boundary layer. Membrane surface roughness facilitates accumulation of colloidal particles in the valley areas [7,43].…”

Direct Observation of Deformation in Microgel Filtration

“…To study the behavior of such real-world soft filter cakes with their complex composition, synthetic soft colloids with previously established properties have been used as model foulants in several experimental and theoretical simulation studies 3–9 . Depending on their size, these synthetic soft colloids represent ideal entities to mimic the mechanical and hydraulic properties of soft biological matter, ranging from proteins to cells and biofilms.…”

Pulsatile Flow in Microfluidic Systems

“…Until this issue is adequately addressed, microfluidic platforms may continue to suffer from a low adoption rate. As a result, there has been a push to understand the complex problem of clogging at the single‐pore and even single‐particle level, to better predict and model the growth of clogs . All of these fundamental clogging studies have focused on steady flow, but recent reports have found that clogging can be effectively mitigated with the aid of oscillatory perturbations.…”