How Much Do You Know About the Material of Filter Membrane?

Filtration is a common step in our experiments. It can not only effectively prevent the clogging of the sieve plate and damage the pump valve, but also avoid the deterioration of peak shape and the generation of impurity peaks. It can be said that filtration plays an important role in the protection of the instrument and the experimental results.

Whether it is a syringe filter or a disc microporous membrane, the first and most important factor we have to consider is its material. For the samples to be filtered with different compositions, we can choose different membrane materials. Here, HAWACH summarizes some conventional and uncommon membrane materials for you.

Commonly used filter membranes

The first introduction is some of our most commonly used materials.
1. MCE (Mixed Cellulose)
Mixed cellulose generally refers to nitric acid-acetic acid mixed cellulose ester filter membrane. MCE material has natural hydrophilicity combined with low protein and is generally used for the filtration of protein and aqueous solutions in biological samples.

2. PES (polyethersulfone)
PES material can be used as a substitute for MCE. It has the characteristics of hydrophilicity, low protein binding, high flow rate, high porosity, and high flux. PES filter membrane is suitable for filtering cell culture media.

3. Nylon (nylon)
The nylon membrane material is aliphatic nylon. Nylon has good hydrophilicity, has a high protein binding type, is suitable for protein-free aqueous and organic solutions, etc., and is resistant to alcohol and DMSO.

4. PVDF (Polyvinylidene Fluoride)
PVDF has good chemical stability and heat resistance, low protein binding, and is suitable for general biological filtration. PVDF filter membrane is not suitable for the filtration of strongly corrosive liquids, and cannot tolerate acetone, DMSO, THF, DMF, di-lv methane, lv-methane, etc.

5. PTFE (Polytetrafluoroethylene)
PTFE has wide solvent compatibility, high flux, high particle retention rate, good temperature resistance, resistance to strong acids, alkalis, organic solvents, and oxidants, and is suitable for filtering strong corrosive solutions, organic solutions, and gases. If you don’t know what material of filter consumables to choose in the experiment, then it is right to try PTFE.

The above are the common types of filtration consumables on the market. Sometimes in the packaging instructions, PES and MCE are called water-based filtration membranes, nylon is called organic filtration membranes, and PVDF and PTFE are called general-purpose ones. Among them, PTFE and PVDF filter membranes are also divided into hydrophilic and hydrophobic. Hydrophilic materials can be additionally used for aqueous solution filtration, so hydrophilic PTFE can be said to be a universal filter material.

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Uncommonly used filter membranes

In ordinary experiments, we can use the above several materials to meet the experimental needs, but there are actually some other types of filter materials, which also have their own characteristics. HAWACH will introduce some uncommonly used filter membranes for you.

1. PP (polypropylene)
PP membrane is a natural hydrophobic filter medium. It has the characteristics of high flux, high dirt holding capacity, and good pressure resistance, and can be sterilized at high temperature, so PP material can be used for the filtration of organic solvents with high particle content.

2. CA (cellulose acetate)
CA refers to a thermoplastic resin obtained by esterification with acetic acid as a solvent and acetic anhydride as an acetylating agent under the action of a catalyst. CA has the advantages of a high flow rate, strong thermal stability, and low protein adsorption. It is generally suitable for filtration of aqueous solutions, protein, and related samples, and also suitable for filtration of low molecular weight alcohols and oils.

3. GF (glass fiber)
GF has the characteristics of high flux and high dirt holding capacity. Its dirt holding capacity is stronger than other cellulose or synthetic materials. It is also suitable for aqueous solvents and organic solvents. It is often used as a pre-filter for difficult-to-filter solvents and is directly added to the filter membrane for use to increase the filtration rate and continuous filtration.

Although filter membranes of similar PP and GF materials are used less, pre-filtration of solvents with more impurities may have a good effect. In the case of adsorbing a large number of particulate impurities, it can save raw materials for your subsequent filtration operations and improve the filtration effect.

In the experiment, we will inevitably encounter unsatisfactory filtration effects and results, which may be caused by poor matching between the filter medium and the solvent to be filtered. If you also encounter this situation, you might as well try several kinds of filter consumables.

HAWACH provides syringe filters or microporous membrane products including the above materials. Its product specifications are rich and we can provide you with free trial packs, so that there is no worry about the cost of raw materials with unknown effects and let you make new attempts. Welcome to contact HAWACH sales team and we believe there is always the product you need.