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@PHDTHESIS{Lken:849734,
author = {Lüken, Arne Can},
othercontributors = {Wessling, Matthias and Ramon, Guy},
title = {{F}rom soft matter filtration processes to microfluidic
filter cake visualization},
volume = {30 (2022)},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2022-07003},
series = {Aachener Verfahrenstechnik series - AVT.CVT - chemical
process engineering},
pages = {1 Online-Ressource : Illustrationen, Diagramme},
year = {2022},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, Rheinisch-Westfälische Technische
Hochschule Aachen, 2022},
abstract = {Membrane ultra- and microfiltration is a chemical unit
operation used to purify and concentrate liquid suspensions
of colloids and particles. Typical industrial applications
are removing or concentrating colloids, proteins, or cells
in water treatment, food processing, and bioprocessing. The
filtration performance suffers from the agglomeration of the
filtrated matter on the membrane surface as a filter cake.
This filter cake adds hydrodynamic resistance on top of the
membrane's resistance and decreases the process's overall
efficiency. Traditional applications measure the resistances
for a specific filtrate at the point of operation and adapt
the process design and the operating conditions accordingly.
This thesis aims to provide mechanistic insights into the
filtration process by developing experimental methods for
microscopic filter cake visualization and applying these
methods to analyze colloid and particle interactions in the
filter cake during filtration. Finally, the thesis presents
a novel ultrafiltration-based lab-scale microgel
purification process and validates the process compared to
state-of-the-art technologies. This thesis developed two
devices for visually observing filter cakes: The first is a
microfluidic system that withholds the filtrated particles
at a membrane-mimicking structure and enables a visual
observation of the filter cake's cross-section. Filtering
soft spherical polyethyleneglycol particles provoked
avalanche-like compaction of the filter cake during cake
built up. The filtration of additive manufactured
non-isotropic any-shape particles showed the dependency of
the hydraulic resistance and the cake morphology from the
particle shape and material. These microscopic particle
scale results give essential insights into the particle
interactions occurring in filter cakes and permeated
assemblies. The second observation device developed and
applied in this thesis is a flat sheet membrane filtration
cell that visually observes the filter cake using Confocal
Laser Scanning Microscopy. During cross-flow cleaning
procedures, microgel filter cakes unravel instability-driven
3D patterns on the cake surface, accelerating cake removal.
Finally, the microscopic filtration results are supplemented
with developing a tangential flow microgel lab-scale
ultrafiltration device. The thesis validates the
applicability of the process for purifying microgels and
reports operational procedures, process quantification, and
the purification's challenges compared to state-of-the-art
technologies. This thesis's findings provide one step
towards bridging the gap between microscopic particle
interactions and filtration cake layer properties. The
presented results need to be incorporated into filtration
models to translate the fundamental phenomena into
applicable separation processes in future works. Finally,
the findings are not only relevant for filter cakes, but
additionally give insights in various applications of
permeated micro-particle assemblies. The properties of
self-assembling microparticle scaffolds, e.g., as tissue in
cell culture, depend strongly on the particle-particle
interactions, the assembly's morphology, and its hydraulic
resistance. This interdisciplinary perspective will transfer
the methods presented here to drive future developments.},
cin = {416110},
ddc = {620},
cid = {$I:(DE-82)416110_20140620$},
pnm = {SFB 985 B06 - Kontinuierliche Trennung und
Aufkonzentrierung von Mikrogelen (B06) (221475706) / DFG
project 191948804 - SFB 985: Funktionelle Mikrogele und
Mikrogelsysteme (191948804)},
pid = {G:(GEPRIS)221475706 / G:(GEPRIS)191948804},
typ = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
doi = {10.18154/RWTH-2022-07003},
url = {https://publications.rwth-aachen.de/record/849734},
}
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