What are the membrane material requirements and types for air filtration

The field of microporous membranes used in the air filtration industry is also particularly extensive. Microporous membranes are used to remove particles, impurities, and dirt (including bacteria, viruses, and other particulate matter) in the air. Then, microporous membranes used in air filtration What requirements should be met?

1. The pore size of the filter membrane should be small enough to filter out small particles. For air filtration applications, the membrane pore size is usually between 0.1 and 1.0 microns.

2. The membrane should have high filtration efficiency, which means it can effectively remove particles in the air.

3. The membrane should not have an excessive effect of inhibiting airflow for air, because high airflow resistance will lead to a decrease in the performance of the system using the membrane, which does not have practical performance.

4. The membrane needs to be strong enough to withstand a large pressure difference without tearing or breaking. Almost all air filtration needs to be completed under the action of external pressure. Strength is the inherent premise of the filter membrane material.

5. The membrane should be resistant to chemicals that may exist in the air or used to clean the membrane. In some industries where chemicals exist, even if they are not related to the production of chemicals, due to the use of gas filtration membranes, particles Adhesion and electron adsorption are inside and on the surface of the membrane, and chemical cleaners are required to remove them.

6. The membrane should be moisture-proof. First, as an air filter membrane, there is a certain amount of moisture in the air, and the hydrophilic membrane will absorb water vapor. In this way, high humidity will reduce the performance of certain types of membranes.

7. The film should remain stable at the temperature exposed during use, that is, the temperature resistance of the film.

So, what are the microporous membrane materials commonly used in air filtration?

1. The most commonly used is polytetrafluoroethylene (PTFE), a fluoropolymer with excellent chemical resistance and thermal stability, and can withstand a wide pH range, usually pH 0 to pH 14 , and can withstand high temperatures, their operating temperature range is usually -200°C to +260°C, and it is hydrophobic, which means it can resist moisture, at the same time, it can also be surface modified to make it hydrophilic Water-based, in chemical-type applications such as chemical, medical, chemical manufacturing or laboratory environments, they are also used in outdoor air filtration systems due to their excellent weather resistance.

2. Polypropylene (PP): PP is a thermoplastic polymer that is resistant to many chemical solvents, bases and acids, usually with a pH range of about 2 to 12, and an operating temperature range of about 70°C to 90 °C, it is also hydrophobic and has good mechanical strength.

3. Polyethylene (PE): PE is another thermoplastic polymer with good chemical and moisture resistance. Typically resistant to a pH range of approximately 4 to 9, with an operating temperature range of approximately -70°C to 80°C, it is often combined with other materials to increase its mechanical strength. PP and PE membranes are commonly used in residential and commercial HVAC systems due to their advantages in filtration efficiency, airflow resistance, and cost.

4. Polyvinylidene fluoride (PVDF): PVDF is a highly non-reactive pure thermoplastic fluoropolymer, which has characteristics such as resistance to solvents, acids and alkalis, and high thermal stability. It usually tolerates a pH range of about 1 to 14, the operating temperature range is usually about -20°C to 150°C, PVDF membranes are usually used in some key filtration applications in high-purity industries, such as pharmaceutical, scientific research and semiconductor industries, etc.

The above is a summary of some membrane materials commonly used in air filtration. For materials, high performance means complex production processes, and high costs are inevitable. With the improvement of some modification and composite technologies, various The performance of the material will be better improved. The above descriptions only represent the general characteristics of some materials. The selection of specific membrane materials will depend on the specific requirements of the application, including factors such as the type of particles to be filtered, operating conditions and cost constraints. , choose the best, it is better to choose the most suitable one, I hope to give you help in membrane selection.