When precision, product quality, or sterility is critical, membrane cartridge filters are the final line of defence in a liquid or gas filtration process. Their ability to provide absolute retention — capturing particles and microorganisms down to submicron levels — makes them essential across industries such as pharmaceuticals, food and beverage, microelectronics, and municipal water treatment.
But not all membranes are the same. One of the key selection criteria is the micron rating — the nominal or absolute pore size of the membrane that determines what contaminants are removed and what passes through. Choosing the correct micron rating ensures optimal process protection without unnecessary pressure drop or premature blockage.
Let’s explore the typical applications of membrane cartridge filters by micron rating, from coarse clarification through to final sterilisation.
At this range, membranes are typically used as prefilters to remove visible particles, rust, and coarse colloids before finer downstream filtration steps.
PES (Polyethersulfone) membranes with absolute ratings in this range are popular, often combined with depth prefilters for staged particle reduction.
This range bridges the gap between particle removal and microbial control. Filters in this class are often termed bioburden reduction filters.
Membranes such as PES, Nylon, or PVDF offer high flow rates and low protein binding in this range.
This is the most critical class of membrane filters in industries where microbial sterility is essential. A 0.2 µm membrane is validated to remove Brevundimonas diminuta — the benchmark organism for sterilising-grade filters.
Hydrophilic PES or PVDF for aqueous solutions; hydrophobic PTFE for gases or solvents. Filters are integrity-testable and validated to pharmaceutical standards (e.g., ASTM F838).
Sub-0.1 µm membranes approach the ultrafiltration boundary, used when extremely high purity or bioburden control is required.
In dry gases PTFE membrane filters can be rerated for virus and phage removal due to the improved performance of the mechanisms of filtration. For more on this read our blog – Ensuring You Use The Optimum Sterile Gas Filter
Advanced PES or PVDF membranes with high throughput and low extractables; PTFE for aggressive solvents and gases.
It should be noted that certain manufacturers offer modified PTFE and PVDF membrane cartridge filters so that they act as hydrophilic membranes.
Selecting the correct membrane micron rating depends on:
Often, a graded filtration train provides the best performance — starting with a depth filter (e.g., 5 µm), followed by a finer prefilter (0.45 µm), and ending with a 0.2 µm sterilising membrane.
|
Micron Rating |
Typical Use |
Common Applications |
Typical Materials |
|
1.0 µm |
Fine clarification |
Prefilter for sterile filters |
PES, Nylon |
|
0.8 µm |
Bioburden reduction |
Wine, beer, pharma buffers |
PES, PVDF |
|
0.45 µm |
Fine microbial control |
Beverage sterilisation, reagents |
PES, Nylon |
|
0.2 µm |
Sterilising-grade |
Pharmaceuticals, WFI, bottled water |
PES, PVDF, PTFE |
|
0.1 µm |
Ultraclean filtration |
Virus/mycoplasma reduction |
PES, PVDF |
Membrane cartridge filters are precision-engineered tools that directly influence product quality, process efficiency, and regulatory compliance. Matching the micron rating to the right application isn’t just about removing particles — it’s about protecting downstream processes, extending filter life, and ensuring consistency from batch to batch.
When in doubt, start with a clear understanding of your process contaminants, product requirements, and validation needs — then work backwards to define your filtration train.
If you have any questions about membrane cartridge filtration, then you can give us a call or send us an email - we’d be more than happy to help.
You can also view our full product ranges for membrane filters or read more in our blogs:
PoreFiltration – Making your filtration systems work harder