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Investigations on the Particle Fouling and Backwash Efficiency During Microplastic Microfiltration-Particle Size
Saeedeh Saremi1,2, Leonie Marie Scheer1, Gerhard Braun1
1Institute for Physical Process Technology, Saarland University of Applied Sciences, 66117 Saarbrücken, Germany.
Abstract:
The characteristics of polystyrene (PS) microplastic (MP) microfiltration by a cellulose acetate (CA) membrane were investigated within this study. Particle sizes and pore sizes were selected in a comparable range in order to challenge the dead-end microfiltration. Backwashing experiments round up the investigations. Microfiltration characteristics and particle size measurements, as well as a particle fouling analysis by different methods, were applied in the study in order to provide a comprehensive picture of particle deposition and particle fouling structuring. The particle removal efficiency was particle-size-dependent, and especially small particles were further reduced during the proceeding filtration, while the larger particles were already removed within the first minutes of filtration. This observation was attributed to the pore blocking (internal and/or complete) and build-up of the filter cake. The difference in the particle-fouling structure at low and elevated filtration pressure significantly influences the backwashing efficiency. The particle fouling resulting from low-pressure filtration was completely removed due to the backwashing procedure applied, while an increased filtration pressure resulted in a different particle-fouling structure, which negatively influenced the backwashing efficiency. This knowledge of the formation and structure of the MP particle fouling and its removal by backwashing is a prerequisite for further process development.
Insights
This study examined polystyrene microplastic filtration using cellulose acetate membranes. Backwashing effectively removed fouling from low-pressure filtration, but high-pressure filtration created a more resistant fouling layer.
Area of Science:
- Environmental Science
- Materials Science
- Chemical Engineering
Background:
- Microplastic (MP) pollution poses environmental challenges.
- Cellulose acetate (CA) membranes are used in microfiltration.
- Understanding microplastic fouling is crucial for water treatment.
Purpose of the Study:
- Investigate polystyrene (PS) microplastic microfiltration using CA membranes.
- Analyze particle deposition, fouling structure, and backwashing efficiency.
- Determine the impact of filtration pressure on fouling and cleaning.
Main Methods:
- Dead-end microfiltration experiments with defined PS particle and CA membrane pore sizes.
- Particle size measurements and particle fouling analysis.
- Backwashing experiments at varying filtration pressures.
Main Results:
- Particle removal efficiency was particle-size-dependent, with smaller particles being filtered more effectively over time.
- Pore blocking and filter cake formation influenced particle removal.
- Low-pressure filtration fouling was fully removed by backwashing.
- High-pressure filtration resulted in a different, less removable fouling structure.
Conclusions:
- Filtration pressure significantly impacts microplastic fouling structure and backwashing efficiency.
- Effective backwashing depends on understanding fouling formation and structure.
- This research provides insights for developing improved microplastic removal processes.
