Factors affecting the filtration efficiency of non-woven fabrics for filtration
As one of the fastest growing fields in the non-woven fabric industry, non-woven fabric materials for filtration have a wide range of applications, such as petroleum, chemical, energy, environment, food and beverage, biopharmaceutical, medical, marine, military, and other fields. The application of non-woven fabric materials in the filtration field has many excellent characteristics, including high filtration efficiency, easy production, low cost, low price, easy composite with other types of materials, and easy deep processing such as pleating and molding on the production line. Therefore, non-woven fabric materials for filtration can gradually replace traditional filtration materials, and their usage will be increasing.
Factors affecting the filtration efficiency of non-woven fabrics for filtration
Structure of non-woven fabric materials
In general, it is required that the filter material be structurally capable of blocking or adsorbing particles and ensuring a certain amount of gas passes smoothly. The filtration effect of filter materials is achieved through their internal pore channels, so the pore size and its distribution have a significant impact on the filtration efficiency of the material.
Research has shown that the smaller the porosity of non-woven materials, the higher the filtration efficiency. This is because when the porosity of the material decreases, the space occupied by fibers in the entire material structure increases, the opportunities for contact with particles increase, and the ability to capture particles is enhanced, thus improving the filtration efficiency of the material. For non-woven materials used for filtration, their structure is closely related to filtration efficiency.
Particle size and shape
The size and shape of particles affect the filtration efficiency of filter materials. As the particle size increases, the diffusion efficiency gradually decreases. Smaller particles will first deposit on the fiber due to diffusion, while larger particles will also deposit on the fiber due to interception and inertia.
Filtering speed
In the case of low filtration speed, as the filtration speed increases, the filtration efficiency decreases. For fibers with the same diameter, as the particle diameter decreases, the fibers become less likely to capture particles, resulting in an increase in particle penetration rate and a decrease in filtration efficiency; For particles with the same particle size, as the fiber diameter increases, the fiber specific surface area decreases, the ability to capture particles weakens, and the particle penetration rate increases, leading to a decrease in filtration efficiency.
Temperature and humidity
Filter materials mainly rely on mechanical effects such as Brownian diffusion, interception, inertial collision, and gravitational deposition to filter particles in the air. When filtering air, increasing the temperature increases the degree of particle diffusion, but as the temperature increases, the viscosity of the gas also increases. Larger particles are less likely to deposit on the fibers due to inertia and gravity, resulting in a significant decrease in filtration efficiency. And after increasing the humidity of the filtered air, the diffusion of particles will increase, and the filtering effect will also significantly decrease.