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Final Filtration to Protect Chemical Product Quality

The quality of the final product often depends on the quality of the final filtration step. Read on for more detailed information, or go to the product selection table at the bottom of this page to explore specific filter options.

The final filtration of product is the most critical filtration process in most operations. It can remove almost all unwanted particles from the product and safeguard quality. The amount of particle removal required varies widely across the industry from the simple removal of visible particles for some bulk chemicals to the removal of virtually all particles and bacteria for high purity chemicals used in pharmaceutical or semiconductor manufacturing.

Housing 3 in the schematic is the only location shown, but “final” filtration could be a multiple step process, depending on the number of particles in the stream and the size distribution of those particles. If the goal is removal of either bacteria or very small, sub-micron sized particles, operators will often use 2 or 3 stages of filtration. Using multiple filter steps most often improves filtration process efficiency and cost-effectiveness. Critical Process Filtration offers services that can help you design your filtration process.

Common Filtration Steps in Chemical Processing
Particle Filtration in Reprocessing

Custom systems are designed for new applications and to solve challenges in existing processes. Critical Process Filtration will work with you to design, build and install a cost-effective system that delivers the results you need. Contact us or visit our custom filtration systems page for more information.

Application Summary

For more information on this specific application, click on the link below to download an Application Summary.

Choosing the Right Filters

With such a wide range of possible filtration goals, the full range of filter technologies available may be used as a final filter. If the goal is removal of visible particles, which generally means removing particles larger than 20 microns, depth filters are used. These could be relatively inexpensive, standard depth filters with thick media that capture particles in the depth of the media. If the particle load is high, then more expensive pleated depth media filters may be used. Pleated filters have a large surface area that will hold a much larger amount of particulate.

If removing haze from the liquid product is the goal, depth filters may still be used, but with the target particle size smaller, perhaps even down to 1 micron. This level of filtration is usually done using pleated depth media filters, though membrane filters may be used for a few applications.

Membrane filters are used to remove bacteria and sub-micron size particles. The pleated membrane filters are the most efficient at removing these size particles, but are almost always protected by prefilters with larger pore sizes.

The filters chosen must, obviously, be compatible with the product, remove the target contaminants, and cannot adversely affect the final product. With multiple filter media materials and filter device types, Critical Process Filtration can help you find the compatible filtration solution that will protect your product, your customers and your brand.

The table below shows the filter media in cartridge, capsule and disc filter configurations. We also have housings for filter cartridges. Click on the PDF Files in the appropriate location to download a data sheet for the filter media and configuration that fits your needs. Critical Process Filtration also has specialty filter devices that may fit your application.

Media Code
Filter Media
Filter Grade
Cartridge Data Sheet
Capsule Data Sheet
Disc Filter Data Sheet
Pore Sizes Avail. (µm)
Melt-Blown Polypropylene Media
1, 3, 5, 10, 20, 30, 50, 75, 100
Continuously spun bonded polypropylene media for consistent 85% nominal performance
Nano-spun Polypropylene Media
1, 3, 5, 7, 10, 20, 30, 40, 50
Very high retention efficiency (99%) and high load capacity to protect downstream processes
Pleated Polypropylene Depth Media
0.1, 0.22, 0.45, 0.65, 1.0, 3.0, 5.0, 10, 20, 30, 40, 60, 100
100% polypropylene construction for high purity
Melt-Blown Nylon Media
1, 3, 5, 10, 20, 30, 50, 75, 100
Spun bonded for consistency with broad chemical compatibility
Pleated Fiberglass Depth Media
0.22, 0.30, 0.45, 0.65, 1.0, 2.0, 3.0, 5.0, 10, 20, 30
High capacity filters for clarification and prefiltration applications
Asymmetric Polyethersulfone (PES) Membrane
0.03. 0.1, 0.22, 0.45, 0.65, 1.8, 1.0, 1.2
Highly asymmetric, hydrophilic PES membrane in single-layer configurations for high efficiency, high flow rates
Symmetric Polyethersulfone (PES) Membrane
0.03. 0.1, 0.22, 0.45, 0.65, 1.8, 1.0, 1.2
Symmetric, hydrophilic PES membrane for high efficiency filtration of water.
Nylon 6,6 Membrane
0.1, 0.22, 0.45, 0.65
For removal of small particles and microorganisms in a wide range of chemicals.
High Capacity Polyethersulfone (PES) Membrane
0.2, 0.5 and 1.0 single layer; 0.5/0.2 and 1.0/0.5 dual layer
High void volume membrane for small particle or bacteria reduction.
High Capacity, Hydrophilic Polyvinylidene fluoride (PVDF) Membrane
0.22, 0.45, 0.65, 1.2
High void volume membrane with high holding capacity for systems that may have high particulate loads.
Polypropylene General Service Grade
0.1, 0.22
Hydrophobic membrane for non-aqueous liquids and gases with excellent material compatibility and low extractables
Polyvinylidene fluoride
(Hydrophobic PVDF)
0.22, 0.45, 0.65, 0.85, 1.0
High capacity, hydrophobic membrane for long life in air and process gas filtration.
PTFE General Service Grade
0.1, 0.22, 0.45, 1.0, 3.0
Highly hydrophobic. Superior air filtration flow rates for tank vent applications

To estimate the number of filters you will need for your application, use our unique sizing tools.

Contact Critical Process Filtration if you have any questions, wish to discuss a specific application or want to learn more about any of our Products and Services. We look forward to hearing from you!