How to Select the Right Membrane Filters

The membrane filter is a micro-porous plastic film with specific pore size ratings. With surface capture, the membranes can retain particles or microorganisms larger than the pore size, and particles smaller than the pore size will be retained by other mechanisms at the same time.

The membrane of high quality not only has the character of strong strength of both burst (longitudinal) and tensile (lateral), high purity reagents, and raw materials, but it also provides high speed of gas and liquid flow by its high porosity.

When you select membrane filters, first you should figure out what kind of liquid or gas will be filtered, and then you need to check which membranes are chemically compatible and the maximum pore size is appropriate to achieve the best results. Don’t forget to consider all the conditions of processing during the filtration, such as temperature. It will help you make the right decision.

In different laboratory sample filtrations, we ensure that the correct membrane filter is selected from different types of filter materials. Here, we summarize the filtration features and applications of different membranes filter. Let’s explore together.

1. Nylon membrane filter

Material: Nylon (Polyamide)

Features: good temperature resistance, can withstand 121 degrees saturated steam thermal pressure sterilization for 30 minutes. Good chemical stability of nylon membrane filter, can withstand dilute acid, dilute alkali, alcohol, oil, hydrocarbon, halogenated hydrocarbon and organic oxide, and other organic and inorganic compounds.

Application: Nylon membrane filter is widely used for electronic, microelectronic, semiconductor industrial water filtration, and tissue media filtration. Liquid medicine filtration, beverage filtration, high purity chemicals filtration, aqueous solution filtration, and organic mobile phase filtration.

2. PVDF membrane filter

Material: Polyvinylidene Fluoride (PVDF)

Features: The PVDF membrane filter has high mechanical strength, high tensile strength, good heat resistance and chemical stability, low protein adsorption rate, strong negative electrostatic, and hydrophobic; It has hydrophobic and hydrophilic forms.

Application: The hydrophobic PVDF is mainly used for the filtration of gas and steam, high-temperature liquid, and the hydrophilic PVDF is mainly used for the purification and filtration of tissue culture solution, additives, and other sterilizing filtration solvents and chemical raw materials, as well as the sterility treatment of reagents and the filtration of high-temperature liquid.

3. MCE membrane filter

Material: Cellulose Acetate and Nitrocellulose

Features: MCE membrane filter pore diameter is relatively uniform, the porosity is high, no medium shedding, the texture is thin, the resistance is small, the filtration is fast, the adsorption is small, the price cost is low, but not resistant to the organic solution and strong acid, strong alkali solution.

Application: The pharmaceutical industry needs a thermal-pressed sterilized injection, large infusion to filter out particles, sterilizing heat-sensitive drugs (insulin ATP, coenzyme A, and other biochemical preparations), using 0.45 or 0.22-micron filter membrane solution in the analysis of particles and oil insoluble substances, and water pollution index measurement.

4. PP membrane filter

Material: Polypropylene (PP)

Features: PP membrane filter has no adhesive, stable chemical properties, is flexible, not easy to damage, has high-temperature resistance, and can withstand high-pressure sterilization.

Application: The PP membrane filter is suitable for making various rough, fine filters, folding filter cores, beverages, medicine, and other industries’ plate and frame press filter membranes. Suitable for reverse osmosis membrane, ultrafiltration membrane support, and pretreatment.PP filter membranes are non-toxic and tasteless and can be used in medicine, the chemical industry, food, beverage, and other fields.

5. PES membrane filter

Material: Polyethersulfone (PES)

Features: PES membrane filter is a hydrophilic filter membrane, with a high flow rate, low dissolution, good strength, no adsorption of protein and extract, and no pollution to the sample.

Application: Low protein adsorption and high drug compatibility, designed for biochemical, testing, pharmaceutical, and antibacterial filtration devices

6. PTFE membrane filter

Material: Polytetrafluoroethylene (PTFE)

Features: PTFE membrane filter has the most extensive chemical compatibility, and can withstand DMSO, THF, DMF, dichloromethane, chloroform, and other strong solvents.

Application: The PTFE membrane filter can filter all organic solutions, especially strong solvents that other membranes cannot tolerate.

7. CA (cellulose acetate)

Material: Cellulose Acetate

Features: Cellulose acetate membrane filter is  hydrophilic, low protein binding, limited tolerance to organic solutions

Application: Filtration of proteins and enzymes; Protein recovery, diagnostic cytology, biological and clinical analysis, degerming of tissue media.

8. GF (glass fiber)

Material: Borosilicate Glass Fiber

Features: Microporous glass fiber membrane filter is hydrophilic, made of borosilicate, and does not contain binders; fast flow rate, high load, can retain very fine particles; biologically inert, except for high concentrations of hydrofluoric acid and alkaline solutions, can withstand Most solvents and reagents; good heat resistance, can withstand the high temperature of 500 °C.

Application: Routine testing of water quality; ambient air exhaust gas monitoring/solid waste leaching toxicity; battery separator, flexible electrode.