Filtration is a technical application of fibers. Fiber materials have become one of the important material choices for filter media due to their fineness and flexibility, together with other basic material properties. Most fibers can be suitable candidates for developing filter media for either one filtration type. Alfa Chemistry provides customers with fiber solutions for filtration applications, according to techno-economic requirements or considerations.
Fiber Filtration
The filtration performance of fibers mainly considers three attributes: fiber selection, fiber properties and end applications.
- Fiber Selection
The selection of suitable fibers considering the material properties is the first task in filter media design. The inherent properties of fiber raw materials determine the basic properties of filter media, including mechanical properties such as strength, elasticity, and wear resistance, and chemical properties such as acid and alkali resistance. Common fiber types used in filtration applications include natural fibers such as cotton and wool, man-made regenerated fibers such as viscose rayon, and synthetic fibers such as polyamide (nylon), polyester (PET), high-performance polyester, polyolefins (polypropylene, polyethylene), aramid, and fluoropolymers (polytetrafluoroethylene [PTFE]). [1]
- Fiber Properties
In terms of performance, basic fiber properties are designed to optimize the material's volume, air permeability and pore size. Bulk and breathability work together and affect dirt holding capacity. Pore size is related to the size of particles that are able to penetrate the media, and this characteristic essentially determines the filtration efficiency. - End Applications
The filter media made of the above-mentioned fiber materials can be further used in a wide range of industries such as metallurgical industry, medical treatment, pharmaceuticals, water treatment, biological cleaning, and food. In all of these applications, the contaminants are predominantly in the form of particles whose typical size values are shown as following. [1]
Advanced Filtration Technology
One of the latest trends in filter media is nanofiber nonwovens. Nanofiltration technology has been developed for the manufacture of high-efficiency filter media, such as high-quality nanofiber filter layers. Air filtration using electrospun fibers to intercept fine particles/volatile organic gases/bacteria has been reported as a relatively new but promising technology. According to classical filtration theory, the stable phase of fiber filtration can be further classified into five trapping mechanisms, namely, interception, inertial impaction, Brownian diffusion, electrostatic deposition, and gravitational effect. [2]
Nanofibers have the following advantages as filter materials:
- Interconnected nanoscale pore structure.
- High specific surface area.
- The ability to incorporate active chemistry on nanoscale surfaces.
- Both initial and ongoing efficiency are higher.
- Lower media pressure drop saves energy.
- The filter element has a longer service life.
- Structurally flexible and can be combined with a variety of substrates.
Related Fiber Series
The following are some fiber series you may be interested in, click to quickly browse related products and services.
References
- Govindharajan Thilagavathi, et al. Handbook of Fibrous Materials, Fibers for Filtration, 2020, 807-830.
- Miaomiao Zhu, et al. Macromolecular Materials and Engineering, 2017, 302(1), 1600353.
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