The airborne particulate removal technology mainly includes mechanical filtration, adsorption, electrostatic dust removal, negative ion and plasma methods, and electrostatic electret filtration.
Mechanical filtration generally captures particles mainly through the following three methods: direct interception, inertial collision, and Brownian diffusion mechanism. The collection effect on fine particles is good but the wind resistance is large. In order to obtain high purification efficiency, the filter element needs to be dense and periodically replaced.
Adsorption is the use of the large surface area of the material and the porous structure to capture particulate contaminants, which are easily blocked and used for gas pollutant removal.
Electrostatic dust removal is a dust collection method that uses a high-voltage electrostatic field to ionize a gas to electrically adsorb dust particles to the electrode. The wind resistance is small, but the effect of trapping large particles and fibers is poor, which causes discharge, and the cleaning is troublesome and time-consuming. Ozone is produced to form secondary pollution.
The principle of negative ion and plasma removal of indoor particulate contaminants is similar. It is caused by charging the particles in the air and coalescing to form larger particles to settle, but the particles are not actually removed, but are attached to the nearby surface. It is easy to cause dust again.