When using filtration for purification of liquids and gases, you may utilize a variety of lab supplies: sieves, membranes, cartridges, or bags. Today, we focus on membranes and the benefits of various materials.
- Cellulose Nitrate (CN) membranes are the membranes most used in laboratory and analytical filtration. These membranes offer exceptional wetting properties and the fastest flow rates with aqueous solutions.
- Cellulose Acetate membranes are a mixture of cellulose triacetate and diacetate. This mixture creates a strong membrane in both lateral and longitudinal directions. This membrane has a low static charge, a very low aqueous extractability, and good solvent resistance to low molecular weight alcohols.
- Mixed Cellulose Ester membrane has a smoother, more uniform surface as compared to pure nitrocellulose membranes. This membrane is commonly used to count or analyze particles in liquids or captured from aerosols.
- Nylon membranes are strong, naturally hydrophilic, and compatible with alcohols and solvents used in HPLC work, along with a broad range of other aqueous solutions.
- Polyethersulfone (PES) membranes are low protein binding and hydrophilic. They do not require external wetting agents, resulting in low extractables. PES membranes typically have fast flow rates and better chemical resistance than cellulose acetate membranes.
- PTFE membranes are highly porous, strong, and inert to most chemically aggressive solvents, strong acids, and bases.
Keep in mind membranes will retain all particles equal to and larger than their pore size.When making your selection, take into account the chemical compatibility of the liquid or gas you are filtering with that of the membrane filter. Also, consider the chemical resistance properties of all parts that will come in contact the filtrate.