Membrane Microfiltration by Recirculating the Surface Flow of a Suspension Droplet

Area of Science:

• Fluid Dynamics
• Membrane Science
• Microfluidics

Background:

• Membrane filtration is crucial for separating particles from liquids.
• Traditional methods can suffer from membrane fouling and reduced efficiency.
• Controlling particle behavior within the suspension is key to improving filtration.

Purpose of the Study:

• To develop and validate a novel Hele-Shaw flow-based method for enhanced membrane filtration.
• To investigate the role of shear-induced particle migration in improving filter performance.
• To optimize experimental parameters for maximizing filtrate yield and efficiency.

Main Methods:

• Utilized a sphere-on-flat, lifted Hele-Shaw cell (SoF-LHSC) with oscillatory motion.
• Employed shadowgraphy to visualize flow dynamics and particle migration.
• Conducted parametric analysis to determine optimal operating conditions.
• Quantified filtration performance using shear diffusivity and cake resistance.

Main Results:

• Demonstrated that shear-induced particle migration effectively drives particles away from the membrane, preventing clogging.
• Identified an optimal plate velocity for filtration, beyond which efficiency diminishes.
• Achieved a filtrate yield of 47.98 ± 13.49% from a 30 μL suspension of 7 μm beads using a 0.4 μm membrane in 5 minutes.
• Showed that increased particle size and reduced membrane resistance enhance filter flux.

Conclusions:

• The SoF-LHSC method offers a promising approach for efficient membrane filtration of particulate suspensions.
• Shear-induced particle migration is a critical factor in enhancing filter performance and longevity.
• The method has potential applications in sample concentration, impurity removal, and filtrate extraction.