Impact of wetting agents on the filtration performance of polymeric ultrafiltration membranes

Kochan, J.; Wintgens, Thomas; Hochstrat, Rita; Melin, Thomas

doi:10.1016/j.desal.2008.01.056

Cited by 43 publications

(27 citation statements)

References 13 publications

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“…The results presented in the literature indicate that even at advanced stages of filtration, the membranes remain partially non-wetted with water, especially for hydrophobic membranes in microporous parts of the structure [35,37]. This incomplete wetting is caused by the non-uniform pore size distribution in polymer networks produced via phase separation.…”

Section: Background On Wettingmentioning

confidence: 99%

“…Membrane wetting is mostly addressed for membrane contactors [30], membrane distillation [27,31,32], microsieves [33], and monoliths [34]. However, literature states that microfiltration and ultrafiltration membrane performance is significantly influenced by its wetting state [35][36][37][38]. Conventionally, commercially available ultrafiltration membranes are pre-filled with a pore stabilizer such as glycerol [39].…”

Section: Background On Wettingmentioning

confidence: 99%

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In-situ investigation of wetting patterns in polymeric multibore membranes via magnetic resonance imaging

Wypysek

Kalde

Pradellok

et al. 2021

Journal of Membrane Science

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Wetting of the membrane to displace air or conditioning liquids is important to exploit the complex porosity of a filtration membrane. This study reveals the details of wetting in multibore membrane based filtration modules. Using magnetic resonance imaging (MRI), we quantify the fluid distribution patterns during initial membrane wetting in dead-end permeation mode. The spatio-temporal evolution of aqueous copper sulfate solution wetting the membrane fibers was investigated as a function of the applied flux, packing density, and position along the membrane module length. Three initial wetting conditions were examined: delivery-state membranes, ethanol-washed and dried (air-filled) membranes, and ethanol-filled membranes. Significant changes in wetting patterns were observed due to interfacial and polymer swelling effects. This in-situ investigation reveals a slow wetting progression over six hours and more to obtain complete wetting, even at high fluxes of 200 LMH. However, an increased flux leads to faster wetting kinetics as the evolving wetting patterns are flux dependent. Packing density of the multibore fibers additionally impacts the wetting kinetics by shifting the prevalent pressure conditions. Although in dead-end mode, the wetting progression is non-uniform along the membrane module length. In addition to this parameter study, different pre-wetting agents' effect on the displacement behavior was investigated in depth. This study helps to understand (a) complex wetting phenomena inside multibore membranes in dead-end filtration, (b) the membranes' interaction with their surroundings due to neighboring membranes, and (c) the effect of the used fluid system for displacement on the resulting wetting patterns.

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Section: Background On Wettingmentioning

confidence: 99%

Section: Background On Wettingmentioning

confidence: 99%

In-situ investigation of wetting patterns in polymeric multibore membranes via magnetic resonance imaging

Wypysek

Kalde

Pradellok

et al. 2021

Journal of Membrane Science

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“…The latter allows for the use of a 50 µm standard graded index multimode lead-in fiber or any other lead-in fiber with a core smaller or equal to 50 µm. The addition of isopropyl alcohol to HF reduces the etching-medium's surface tension, improves the wetting of the gutter region 26 , and thus results in the creation of a deeper gutter. Similarly, the temperature reduction of the etching agent improves the etching selectivity of the P 2 O 5 -doped region 25 .…”

Section: Sensor Design and Manufacturingmentioning

confidence: 99%

All-fiber micro-machined Fabry-Perot strain sensor

Pevec

Đonlagić

2012

SPIE Proceedings

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This paper presents the design, fabrication process, and experimental evaluation of a high-sensitivity, all-silica, all-fiber, micro machined Fabry-Perot strain-sensor. This sensor has a short Fabry-Perot cavity and thus allows for the application of low-resolution spectral interrogation systems; in our case the commercial white light signal interrogator was used. The fabrication process includes the design and production of special sensor-forming optical-fiber. This fiber includes a central titanium-doped region, a phosphorus doped-ring surrounding a titanium doped region, and pure silica cladding in order to produce the proposed sensor, two sections of sensor forming fiber are cleaved and etched in a HF/IPA solution. The phosphorus-doped region etches at a considerably higher rate than the other fiber-sections, and thus creates a deep gutter on the cleaved fibers frontal surface. The titanium-doped region etches at a rate that is, to some extent, higher than the etching-rate of pure silica, and thus creates a slightly retracted surface relative to the pure silica fiber-cladding. The etched fibers are then re-spliced to create an all-silica strain sensor in "double configuration", which has a section of etched sensor-forming fiber on both sides. Thus this sensor has a long active length, whilst the length of the Fabry-Perot cavity can be adjusted by a titanium-doping level. The central titanium-doped region also creates a waveguide structure that is used to deliver light to the cavity through one of the fibers. The proposed fabrication process is cost-effective and suitable for high-volume production. The greatest achievement of the depicted in-line strain sensor is the extension of its active sensor length, which is more than 50 times greater than the sensor-cavity's length, and is thus approximately 50 times more sensitive to strain. This sensor also exhibits low-intrinsic temperature sensitivity.

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“…Thus, swelling was not expected to be a major reason for the improvement in water flux observed here. The polysulfone supporting layer was hydrophobic and could not be completely wetted by water 23 . Compared to water, ethanol had a lower surface tension, thus, could easily penetrate into the porous structure and prewet the pores of the polysulfone supporting layer for subsequent water permeation 23,24 .…”

Section: Pure Water Flux Under Different Conditionsmentioning

confidence: 99%

Performance of a seawater-driven forward osmosis process for pre-concentrating digested sludge centrate: organic enrichment and membrane fouling

Ansari

Hai

et al. 2018

Environ. Sci.: Water Res. Technol.

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Impact of wetting agents on the filtration performance of polymeric ultrafiltration membranes

Cited by 43 publications

References 13 publications

In-situ investigation of wetting patterns in polymeric multibore membranes via magnetic resonance imaging

In-situ investigation of wetting patterns in polymeric multibore membranes via magnetic resonance imaging

All-fiber micro-machined Fabry-Perot strain sensor

Performance of a seawater-driven forward osmosis process for pre-concentrating digested sludge centrate: organic enrichment and membrane fouling

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