A Study On The Classification Performance Of The Filtration Material And Filter For PM2.5

With the development of society and the rapid growth of the human?s living standards, the environment has been seriously contaminated. While, people?s expectations for the air quality in living and industrial environments keep increasing. Especially, indoor air quality has a significant impact on people?s health. People have shifted their attentions from PM10 to PM2.5 now. Air filtration is one of the most simple and common way to remove PM2.5 from the air streams. The common devices of air filtration are air purifier and air filter. Air filtration material?s performance will directly affect the performance of air filters.Firstly, a method to calculate the filtration efficiency and resistance of the fiber filter is proposed. Some variables which influence the performance of air filtration, such as: fiber diameter, thickness, pore size, fill rate and aerosol particle size are considered. The rules of how these variables influence the performance of air filtration material are revealed. The results will give a theoretical guidance for the preparation of new types of air filtration materials.A thoroughly investigation on the different test methods for air filter performances are conducted. Two test boards are self-built and one commercial test is bought for different testing purposes, they have different dust source. Their testing errors are analyzed and their applicability in laboratory are validated.Some typical filtration materials with good performance are purchased from market. They are ordinary fiber filter material, electret filter material and tectorial membrane filter material. Structures of the samples are characterized by using scanning electron microscopy and the pore size tester. Then the samples are tested on the test boards. It can be found that the relations between the performance and the microstructure of ordinary material conforms to the theoretical derivations. Electret filter material and tectorial membrane filter material possess the characteristic of high efficiency and low resistance. So one direction of the preparation of new type of air filtration material can be put forward. The filter material can be made of fibers that are coupled with electric charges or possess electric charges itself. Another choice is making composite filter material with different materials.A test board for testing the classification performance of the air filter is set up. It can be found that the filtration efficiency of the filters decline 8%-10% for the particles ranged from 0.3 μm to 1.0 μm, and 1%-3% for the particles ranged from 1.0 μm to 2.5 μm, however, the resistance increase 40%-50% at the same time. For the same air flow rate, filtration efficiency of filters increase with an increase in pleat depth. The resistance of filters decrease at first and then increase with an increase in pleat depth. The impacts of the face velocity on the filtration performance are the similar for the filters and the corresponding filer materials.