Features and Uses of Filter Membranes
The membrane filter is a filter made of a membrane having a certain pore size (a polymer is used as a material such as a cellulose acetate membrane and a nylon membrane). The pores on the surface are irregular shapes. The core component of the membrane filter is a membrane, a membrane that is filled with finer pores on a microporous support layer. There are many materials for making membranes, which are classified into organic membranes (such as polysulfone hollow fiber membranes) and inorganic membranes.
Membrane filters can be used to filter bacteria or collect microorganisms, sediments, and macromolecules from solvents. Because of the mild operating conditions, the membrane filter is preferred in industrial applications.
1. Nylon filter membrane
Features: Good temperature resistance, can withstand 121℃ saturated steam autoclaving for 30min, with a maximum working temperature of 60℃and good chemical stability, which can withstand a variety of organic and inorganic compounds such as dilute acids, bases, alcohols, esters, oils, hydrocarbons, halogenated hydrocarbons, and organic oxides.
Uses: water filtration, tissue culture media filtration in electronics, microelectronics, and semiconductor industry. Filtration of liquid chemicals, beverages, highly purified chemicals, aqueous solution, and organic mobile phase.
2. PVDF filter membrane
Features: high mechanical strength, high tensile strength, good heat resistance and chemical stability, and low protein adsorption rate; it has strong negative static and hydrophobic properties; it has both hydrophobic and hydrophilic forms. But it cannot tolerate acetone, DMSO, THF, DMF, dichloromethane, chloroform, etc.
Uses: Hydrophobic ones are mainly used for air and steam filtration and high-temperature liquid filtration; hydrophilic ones are mainly used for the purification and filtration of sterilization filtration solvents and chemical raw materials such as tissue culture media and additives, aseptic treatment of reagents, and filtration of high-temperature liquids.
3. Mixed cellulose ester filter membrane
Features: relatively uniform pore size, high porosity, no medium shedding, thin texture, small resistance, fast filtration speed, minimal adsorption, low cost of use, but not resistant to organic solutions and strong acid and alkali solutions.
Uses: The pharmaceutical industry needs autoclaved water injection to filter out particles during large infusion; the sterilization of heat-sensitive drugs; analysis and determination of particulates and oil insoluble in solution, and determination of water pollution index. It is also applied to scientific research departments such as somatic hybridization and mitochondrial prediction of heterosis.
4. Polypropylene filter membrane
Features: No adhesive, stable chemical properties, flexible, not easy to break, high-temperature resistance, which can withstand high-pressure sterilization, non-toxic and tasteless, acid and alkali resistant.
Uses: Used in the fields of medicine, chemical industry, food, beverage, etc.
5. PES filter membrane
Features: The microporous membrane made of ether sulfone is a hydrophilic membrane, with a high flow rate, low leachable, and good strength. It does not adsorb proteins and extracts and pollutes the sample.
Uses: Low protein adsorption and high drug compatibility, specially designed for biochemical, inspection, pharmaceutical, and sterilization filtration devices.
6. PTFE filter membrane
Features: The most extensive chemical compatibility, which can withstand strong solvents such as DMSO, THF tetrahydrofuran, DMF dimethylformamide, dichloromethane, and chloroform.
Application: Filtration of all organic solutions, especially the filtration of strong solvents that other filter membranes cannot tolerate.
