Hollow fiber dead-end ultrafiltration: Influence of ionic environment on filtration of alginates

Ven, W.J.C. van de; Sant, K. van 't; Punt, Ineke G.M.; Zwijnenburg, A.; Kemperman, A.J.B.; Meer, W.G.J. van der; Weßling, Matthias

doi:10.1016/j.memsci.2007.09.062

Cited by 101 publications

(67 citation statements)

References 32 publications

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“…In both cases, contaminants build up on the surface and reduce the permeability of the membrane to the fluid, as filtering progresses. This effect, termed concentration polarization (or fouling when the contaminants physically block the membrane pores) poses one of the most significant challenges limiting membrane filtration [4][5][6]. Concentration polarization is greatly reduced in crossflow filtration, due to the flow occurring tangential to the membrane, which sweeps the contaminants downstream and limits build-up of contaminants at the surface.…”

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confidence: 99%

“…Unlike in crossflow filtration, fouling is not controlled via recirculation but can be minimized by incorporating very short automatic backwashes at regular frequencies [3][4][5], in which the imposed pressure gradient (and hence the flow) is reversed to dislodge the contaminants that have built up at the surface [9][10][11]. The lack of recirculation in direct-flow filtration results in lower flow rates (and thus a lower axial pressure gradient) to achieve permeate fluxes comparable to those of crossflow filtration, and so many finer feed channels may be used [12].…”

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confidence: 99%

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Optimizing the operation of a direct-flow filtration device

Herterich

Field

et al. 2016

J Eng Math

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Direct-flow filtration is a common technique for filtering impurities from a fluid using a porous-walled channel or a pipe, one end of which is closed off with a cap. Pure fluid flows out of the porous walls, while impurities are left in the channel. Such systems are composed of a series of individual porous channels or pipes stacked in close proximity. We develop a mathematical model for the flow in a 2D filtration channel and a 3D pipe, with a capped end, to describe the behaviour within a direct-flow device. We study the axial dependence of the transmembrane pressure (TMP) across the membrane walls on the imposed flux, wall permeability and the proximity of the neighbouring fibres. The mathematical models derived are used to predict the operating regimes of the device that maximize the spatial uniformity in the TMP and thus optimize the use of the entire membrane area. We show how a large portion of the available membrane area is not used when the fibres are packed too closely together, with the majority of the filtration behaviour being localized near to the impermeable capped end; this leads to inefficient filtration. We quantify the device performance by examining the uniformity of the filtration across the length of the device and the output of the filtered fluid for a given operating pressure.

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Optimizing the operation of a direct-flow filtration device

Herterich

Field

et al. 2016

J Eng Math

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“…The addition of KCl was investigated in order to assure a denser layer, since the polysaccharide chains are less extended in the presence of such non-gelling ions [10] .…”

Section: Integral Membranesmentioning

confidence: 99%

“…This potential feature was exploited here aiming the stabilization of the protein inside the solid membrane. In addition to it, it is also worthwhile to consider that recent research in sodium alginate ultrafiltration shows that this polyelectrolyte has different conformations in aqueous solution as a function of the ionic environment [10] . Therefore, regarding to the synthesis of a dense composite membrane, the top layer density could be controlled by adding non-gelling ions to the polymeric aqueous solution.…”

Section: Introductionmentioning

confidence: 99%

Immobilization of myoglobin in sodium alginate composite membranes

et al. 2015

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SbstractThe immobilization of myoglobin in sodium alginate films was investigated with the aim of evaluating the protein stability in an ionic polymeric matrix. Myoglobin was chosen due to the resemblance to each hemoglobin tetramer. Sodium alginate, being a natural polysaccharide, was selected as the polymeric matrix because of its chemical structure and film-forming ability. To improve the mechanical resistance of sodium alginate films, the polymer was deposited over the surface of a cellulose acetate support by means of ultrafiltration. The ionic crosslink of sodium alginate was investigated by calcium ions. Composite membrane characterization comprised water swelling tests, water flux, SEM images and UV-visible spectroscopy. The electrostatic interaction between the protein and the polysaccharide did not damage the UV-visible pattern of native myoglobin. A good affinity between sodium alginate and cellulose acetate was observed. The top layer of the dense composite membrane successfully immobilized Myoglobin, retaining the native UV-visible pattern for two months.

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“…These techniques provide no insight into local fouling phenomena which might change along the membrane's long axis due to local variations of the transmembrane pressure (TMP) or axial dependency of the flux along the hollow fiber module. 8 Therefore it would be desirable to use complementary characterization techniques to gain more information into these spatially varying fouling phenomena. Common techniques like scanning electron microscopy (SEM) have significant disadvantages since drying and coating steps alter the characteristics of the fouling layer at the membrane surface.…”

Section: Introductionmentioning

confidence: 99%

New insights into sodium alginate fouling of ceramic hollow fiber membranes by NMR imaging

et al. 2016

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Ceramic hollow fiber membranes are investigated with respect to the fouling behavior. Constant pressure dead-end filtration experiments have been performed using alginate as model substance for extracellular polymeric substances. In addition to the evaluation of the filtration data using conventional cake filtration model, nuclear magnetic resonance imaging (MRI) was used to elucidate the influence of Ca 21 on the fouling layer structure for alginate filtration within ceramic hollow fiber membranes. To visualize the alginate layers inside the opaque ceramic hollow fiber membranes by means of MRI, specific contrast agents were applied. Supplementary to multi slice multi echo imaging, flow velocity measurements were performed to gain more insight into the hydrodynamics in the fouled membranes. MRI reveals the structure of the alginate layers with the finding that the addition of Ca 21 to the alginate feed solution promotes the formation of a dense alginate gel layer on the membrane's surface.

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Hollow fiber dead-end ultrafiltration: Influence of ionic environment on filtration of alginates

Cited by 101 publications

References 32 publications

Optimizing the operation of a direct-flow filtration device

Optimizing the operation of a direct-flow filtration device

Immobilization of myoglobin in sodium alginate composite membranes

New insights into sodium alginate fouling of ceramic hollow fiber membranes by NMR imaging

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