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Quantifying Charge Effects on Fouling Layer Strength and (Ir)Removability during Cross-Flow Microfiltration
Mads Koustrup Jørgensen1, Tuve Mattsson2,3
1Center for Membrane Technology, Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, DK-9220 Aalborg Øst, Denmark.
Membranes
|January 6, 2021
Summary
Membrane fouling, a key limitation in membrane technology, was studied using fluid dynamic gauging (FDG). The study found that calcium ions significantly increase cake cohesive strength, impacting foulant irremovability.
Area of Science:
- Membrane science and technology
- Surface chemistry
- Colloid science
Background:
- Membrane fouling limits the application of membrane technology.
- Understanding fouling mechanisms and parameters affecting layer removability is crucial.
- Current methods for assessing fouling layer strength are limited.
Purpose of the Study:
- To investigate the influence of charge effects on cake cohesive strength using fluid dynamic gauging (FDG).
- To assess the impact of cations, specifically calcium ions, on the cohesive strength and irremovability of fouling layers.
- To propose a method for determining cake irremovability using FDG.
Main Methods:
- Microfiltration (MF) membranes were fouled using negatively charged polystyrene-polyacrylic acid core-shell particles in a cross-flow system.
- Fluid dynamic gauging (FDG) was employed to estimate fouling cake thickness and cohesive strength.
- Cake irremovability was assessed using an FDG-based procedure, comparing layers formed with and without calcium ions.
Main Results:
- Fouling layers formed in the presence of calcium ions exhibited significantly higher cohesive strength than those formed without calcium ions.
- Calcium ions act as a bridging agent between negatively charged foulant particles, increasing cake strength.
- Highly negatively charged particles formed more cohesive cakes in the presence of calcium ions compared to less charged particles.
Conclusions:
- Fluid dynamic gauging (FDG) is an effective tool for assessing cake cohesive strength and foulant irremovability.
- Foulant surface charge and the ionic composition of the solution, particularly the presence of cations like calcium, significantly influence cake cohesive strength.
- FDG can provide in-depth understanding of fouling mechanisms relevant to membrane process optimization.
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