Abstract

On-Line Visualization of Colloidal Filter Cake Motions

Arne Lüken, PhD student, RWTH Aachen University

Membrane ultrafiltration is a low-energy unit operation for soft matter or colloid purification. This process suffers from the agglomeration of the filtrated matter on the surface of the membrane, the so-called gel layer or filter cake. This undesirable cake layer rises the resistance for the fluid permeating the membrane, and thus, increases the energy consumption of the process. In this study, the authors visualize the motion of a soft colloid cake layer using laser scanning confocal microscopy inside a microfluidic filtration module. They analyze the filter cake’s organization and its dynamic motion while performing widely applied cleaning strategies, such as backflushing and crossflow flushing. They present the inner organization of the cake and find responsive 3D-motions of the filter cake under shear stress. This unique cake behavior suggests new strategies for filtration processes and additionally demonstrates the potential of applying microfluidic analysis methods to macroscopic research fields.