Fouling behavior of microstructured hollow fibers in cross-flow filtrations: Critical flux determination and direct visual observation of particle deposition

Çulfaz Emecen, Pınar Zeynep
Wessling, M.
Lammertink, R.G.H.
The fouling behavior of microstructured hollow fiber membranes was investigated in cross-flow filtrations of colloidal silica and yeast. In addition to the as-fabricated microstructured fibers, twisted fibers made by twisting the microstructured fibers around their own axes were tested and compared to round fibers. In silica filtrations, the three different fibers showed similar behavior and increasing Reynolds number increased the critical fluxes significantly. In yeast filtrations, the twisted fiber performed similar to the round fiber and better than the structured fiber. Among the three fibers, during yeast filtrations the critical flux for irreversibility was highest for the twisted fiber. The Reynolds number had little effect on the critical fluxes for particle deposition, which was attributed to the strong adsorption of yeast particles on the membrane. On the other hand, the critical fluxes for irreversibility increased with increasing Reynolds number for all three fibers. Direct visual observation of yeast particles on the surface of the three different hollow fibers revealed that for the structured and twisted fibers, the initial deposition rate on the fins is much lower than that in the grooves. This is attributed to the shear-induced migration of the yeast particles from areas of high shear (fins) to those of low shear (grooves). Furthermore, on the fins of the twisted fiber the deposition rate was lower than that on the fins of the structured fiber. This observation, together with the observed high critical fluxes for the twisted fiber led to the conclusion that the twisting induces a secondary flow in the liquid. This secondary flow is effective in depolarizing the buildup of micron-sized yeast particles since the diffusion of these particles is strongly effected by gradients in shear rate. On the other hand, for the silica colloids which are much smaller, shear-induced diffusion is not significant and twisting does not have an improving effect on filtration.
Journal of Membrane Science


Helical hollow fibers via rope coiling: Effect of spinning conditions on geometry and membrane morphology
Yucel, Hazal; Çulfaz Emecen, Pınar Zeynep (Elsevier BV, 2018-08-01)
Helical hollow fiber membranes from poly(ether sulfone) were spun via dry-wet spinning, making use of the liquid rope coiling phenomenon. The polymer solution composition was changed by varying the coagulation value and adding PEG400 as pore former. The bore liquid composition, outer coagulation bath temperature, air gap, polymer dope and bore liquid flowrates were varied to map the conditions where helical fibers form. It was observed that increasing air gap changed fiber geometry from straight to helical....
Fouling behavior of microstructured hollow fiber membranes in dead-end filtrations: Critical flux determination and NMR imaging of particle deposition
Çulfaz Emecen, Pınar Zeynep; Utiu, Lavinia; Kueppers, Markus; Bluemich, Bernhard; Melin, Thomas; Wessling, Matthias; Lammertink, Rob G. H. (2011-03-01)
The fouling behavior of microstructured hollow fibers was investigated in constant flux filtrations of colloidal silica and sodium alginate. It was observed that the fouling resistance increases faster with structured fibers than with round fibers. Reversibility of structured fibers' fouling was similar during silica filtrations and better in sodium alginate filtrations when compared with round fibers. The deposition of two different silica sols on the membranes was observed by NMR imaging. The sols had dif...
Polycarbonate-polypyrrole mixed matrix gas separation membranes
Hacarlioglu, P; Toppare, Levent Kamil; Yılmaz, Levent (Elsevier BV, 2003-11-01)
The gas separation properties of the polycarbonate-polypyrrole mixed matrix membranes were evaluated based on the introduction of conducting polymer as powder fillers. The electrically conductive fillers are obtained from two main synthesis routes namely electrochemical and chemical methods. The permeation properties of polycarbonate-polypyrrole systems are highly dependent on the synthesis method (electrochemical or chemical) and also the membrane casting conditions (casting solvent type). The introduction...
Development of enhanced ultrafiltration methodologies for the resolution of racemic benzoin
Olceroglu, Ayse Hande; Çalık, Pınar; Yılmaz, Levent (Elsevier BV, 2008-09-15)
In the scope of achieving the separation of chiral molecules, enzyme enhanced ultrafiltration (EEUF), a new method based on polymer enhanced ultrafiltration (PEUF), utilizing apoenzymes as ligands, was developed. Benzoin was chosen as the model chiral molecule. Bovine serum albumin (BSA) and apo form of benzaldehyde lyase (BAL) (E.C. were used as chiral ligands in PEUF and EEUF experiments, respectively. In order to bind to the target enantiomer well, the addition of ligand to the benzoin solution...
Fouling behavior of microstructured hollow fiber membranes in submerged and aerated filtrations
Çulfaz Emecen, Pınar Zeynep; Lammertink, R.G.H. (2011-02-01)
The performance of microstructured hollow fiber membranes in submerged and aerated systems was investigated using colloidal silica as a model foulant. The microstructured fibers were compared to round fibers and to twisted microstructured fibers in flux-stepping experiments. The fouling resistances in the structured fibers were found to be higher than those of round fibers. This was attributed to stagnant zones in the grooves of the structured fibers. As the bubble sizes were larger than the size of the gro...
Citation Formats
P. Z. Çulfaz Emecen, M. Wessling, and R. G. H. Lammertink, “Fouling behavior of microstructured hollow fibers in cross-flow filtrations: Critical flux determination and direct visual observation of particle deposition,” Journal of Membrane Science, pp. 210–218, 2011, Accessed: 00, 2020. [Online]. Available: