Macro, Micro, Ultra, and Nano Filtration

Before you get started, you should have a good idea of what you are filtering and what you hope to achieve with the filtration process. With that base understanding, you can segment your process into either macro, micro, ultra, or nano filtration. These are just fancy ways to classify particle size, helping to narrow down the right filter type.

Each of these terms, while related to the size of particles, also has numerical values that help fine-tune the process. There is some overlap between these segments, but they serve as a good starting point.

Below is a chart illustrating the relative sizes of various particles to help you better visualize the filtration scale.

Filtrate, Retentate, Clarification, and Solids Recovery

After understanding what you are looking for and its relative size, you can begin to think about the filtration process itself. Do you want to remove your target particles from the solution, or do you want to remove everything but your target?

Chemical Compatibility

In many scientific, chemical, or pharmaceutical applications, it's possible to encounter chemicals that may react with filtration materials. To prevent a hazardous reaction or the destruction of key samples, it's important to understand that some filtration media offer exceptional chemical resistance, while others may decay or degrade if exposed to an incompatible solution.

With millions of possible chemical compounds and solutions, it would be impractical to provide a comprehensive list of compatible uses for each membrane type. It is highly recommended to have several resources at hand to verify compatibility before performing any filtration process that could compromise the health and safety of laboratory personnel or the efficacy of your samples.

Volume and Load Characteristics

Next, examine the total volume of material to be filtered and the particle load. These two factors have a significant impact on which filter format is most appropriate for your application.

Filter Type Selection

Once you have defined your filtration scale, process goal, chemical compatibility requirements, and volume, you can begin selecting a specific filter type. Tisch Scientific offers a full range of filter formats to cover every application.

Membrane Material Selection

The membrane material determines chemical compatibility, protein binding characteristics, and wettability. Below is a summary of the most common membrane materials and their recommended applications.

Pore Size Selection

Once the membrane material is selected, the final variable is pore size. The correct pore size depends entirely on the target particle or organism you need to retain or remove.