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

Arndt, F.; Roth, U.; Nirschl, Hermann; Schütz, Steffen; Guthausen, Gisela

doi:10.1002/aic.15226

Cited by 37 publications

(28 citation statements)

References 37 publications

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“…In former experi ments, loose polarization layers or gel layers could be observed. [19][20][21] Ca 21 ions were added in form of CaCl 2 (Sigma Aldrich) with a concentration of c Ca 21 2mmol/L. Due to the poor contrast between alginate and water a contrast agent (Magnetite Alginate 100 MagAlg100, also named MION) 22 was added to the feed solution in concentrations of 1 mM and below.…”

Section: Feed Solutions With Contrast Agentsmentioning

confidence: 99%

In‐situcharacterization of deposits in ceramic hollow fiber membranes by compressed sensing RARE‐MRI

et al. 2018

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Ultrafiltration with ceramic hollow fiber membranes was investigated by compressed sensing rapid acquisition relaxation enhancement (CS-RARE) magnetic resonance imaging (MRI) to characterize filtration mechanisms. Sodium alginate was used as a model substance for extracellular polymeric substances. Dependent on the concentration of divalent ions like Ca 21 in an aqueous alginate solution, the characteristics of the filtration change from concentration polarization to a gel layer. The fouling inside the membrane lumen could be measured by MRI with a CS-RARE pulse sequence. Contrast agents have been used to get an appropriate contrast between deposit and feed. The lumen was analyzed quantitatively by exploring the membrane's radial symmetry, and the resulting intensity could be modeled. Thus, different fouling mechanisms could be distinguished. CS-RARE-MRI was proven to be an appropriate in situ tool to quantitatively characterize the deposit formation during in-out filtration processes. The results were underlined by flux interruption experiments and length dependent studies, which make it possible to differentiate between gel layer or cake filtration and concentration polarization filtration processes.

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Section: Feed Solutions With Contrast Agentsmentioning

confidence: 99%

In‐situcharacterization of deposits in ceramic hollow fiber membranes by compressed sensing RARE‐MRI

et al. 2018

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“…MRI was used for an in situ analysis of many membrane processes . MRI allows not only a measurement in an optically transparent setup but is also a non‐invasive analysis method in opaque ceramic hollow fibers that are used in this publication …”

Section: Introductionmentioning

confidence: 99%

“…[17,[26][27][28][29] MRI allows not only a measurement in an optically transparent setup but is also a non-invasive analysis method in opaque ceramic hollow fibers that are used in this publication. [17,[30][31][32][33][34] 2 | EXPERIMENTAL…”

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confidence: 99%

In situ measurement of deposit layer formation during skim milk filtration by MRI

Schork

Schuhmann

Nirschl

et al. 2019

Magnetic Reson in Chemistry

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Filtration and separation via membranes are key processes in food processing. One major application of membrane filtration is in the dairy industry, aiming for the separation of different milk proteins. The various chemical components of milk possess different physiochemical properties and can be used most effectively in food processing if they are separately available and remain in their native state. Microfiltration of skim milk allows a fractionation of the milk proteins casein and whey by size. A deposit is formed on the membrane surface mainly but not exclusively by micellar casein proteins during filtration. Membrane pore blockage by whey proteins and fouling occur during membrane filtration, negatively affecting the yield of the whey protein fraction. Skim milk filtration and the deposit layer formation were measured time and spatially resolved by in situ magnetic resonance imaging (MRI). The nature of the fouling layer was investigated during dead‐end filtration in ceramic hollow fiber membranes. MRI was used to further clarify the influence of operating conditions on separation and filtration mechanisms that are responsible for growth of the fouling layer and its reversibility. The MRI measurements were analyzed for a detailed description of skim milk filtration by modeling the signal intensity distribution.

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“…Gel heterogeneities were detected in transverse relaxation T 2 maps (Fabich et al, ). Filtration processes have been imaged in hollow fiber membranes using alginate as model system (Arndt, Roth, Nirschl, Schütz, & Guthausen, ). Basic knowledge gained from investigations of artificial biofilms can be transferred to real biofilm systems.…”

Section: Introductionmentioning

confidence: 99%

NMR investigation of water diffusion in different biofilm structures

Herrling

Weisbrodt

Kirkland

et al. 2017

Biotech & Bioengineering

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Mass transfer in biofilms is determined by diffusion. Different mostly invasive approaches have been used to measure diffusion coefficients in biofilms, however, data on heterogeneous biomass under realistic conditions is still missing. To non-invasively elucidate fluid-structure interactions in complex multispecies biofilms pulsed field gradient-nuclear magnetic resonance (PFG-NMR) was applied to measure the water diffusion in five different types of biomass aggregates: one type of sludge flocs, two types of biofilm, and two types of granules. Data analysis is an important issue when measuring heterogeneous systems and is shown to significantly influence the interpretation and understanding of water diffusion. With respect to numerical reproducibility and physico-chemical interpretation, different data processing methods were explored: (bi)-exponential data analysis and the Γ distribution model. Furthermore, the diffusion coefficient distribution in relation to relaxation was studied by D-T maps obtained by 2D inverse Laplace transform (2D ILT). The results show that the effective diffusion coefficients for all biofilm samples ranged from 0.36 to 0.96 relative to that of water. NMR diffusion was linked to biofilm structure (e.g., biomass density, organic and inorganic matter) as observed by magnetic resonance imaging and to traditional biofilm parameters: diffusion was most restricted in granules with compact structures, and fast diffusion was found in heterotrophic biofilms with fluffy structures. The effective diffusion coefficients in the biomass were found to be broadly distributed because of internal biomass heterogeneities, such as gas bubbles, precipitates, and locally changing biofilm densities. Thus, estimations based on biofilm bulk properties in multispecies systems can be overestimated and mean diffusion coefficients might not be sufficiently informative to describe mass transport in biofilms and the near bulk.

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

Cited by 37 publications

References 37 publications

In‐situcharacterization of deposits in ceramic hollow fiber membranes by compressed sensing RARE‐MRI

In‐situcharacterization of deposits in ceramic hollow fiber membranes by compressed sensing RARE‐MRI

In situ measurement of deposit layer formation during skim milk filtration by MRI

NMR investigation of water diffusion in different biofilm structures

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