Dr. Hwang Seong-yeon (left), Park Je-young (center), and Oh Dong-yeop (right) of the Korea Research Institute of Chemical Technology’s Biochemistry Research Center are holding a’biodegradable mask filter and nano chitin solution’. [사진=한국화학연구원 제공]
A biodegradable mask filter that is easy to breathe and is reusable has been developed.
The Korea Research Institute of Chemical Technology announced on the 22nd that the research team of Dr. Seongyeon Hwang, Dongyeop Oh, and Jeyoung Park developed a new eco-friendly biodegradable mask filter that compensates for the disadvantages of the existing mask filter while being 100% decomposed.
100% biodegradation in composting conditions within a month, complementing the shortcomings of existing mask filters, making it easy to breathe and using multiple times, N95 (based on US mask filters. Blocks more than 95% of 0.3 micrometer microparticles floating in the air). to be.
After the spread of Corona 19, masks have become a necessity, and mask waste that cannot be disassembled and recycled is causing serious environmental pollution. In particular, the filter is made of polypropylene, such as a plastic straw material, so it does not rot in the soil.
The electrostatic filter method, which occupies 90% of commercial masks, is a principle that creates a space by crossing plastic fibers strands and generates static electricity in the space to attach viruses or fine dust. Static electricity is more susceptible to moisture because it occurs when it is dry. In addition, it is designed to generate static electricity temporarily, so the filter function does not last long.
Another method of manufacturing a mask filter is to make the space between the strands of plastic fibers intersected to make the space between them dense so that viruses or fine dust cannot pass through. As the empty space is narrow, there is a disadvantage that it is difficult for people to breathe due to insufficient ventilation.
The research team made up the shortcomings of these two filter methods to create a new concept biodegradable mask filter that is resistant to moisture and can be reused multiple times, while being easy to breathe.
Polybutylene succinate (PBS), a representative biodegradable plastic, was firmly supplemented with its own technology, and then it was pulled out in the form of thin nanofibers and microfibers, and then the fibers were stacked to make a nonwoven fabric. The final filter is completed by coating this nonwoven fabric with chitosan nanowhiskers extracted from nature.
The new filter compensates for the shortcomings of both methods by utilizing both the method of making foreign substances stick to the surface of the coating with electric charges and the method of filtering foreign substances like a sieve.
Then, the chitosan nanowhisker coating was used to attach viruses and fine dust to increase the trapping ability of foreign substances. Like a magnet, the virus on the cathode sticks to the chitosan coating on the anode and cannot pass through the mask. Since it uses the principle of charge rather than static electricity, it is not susceptible to moisture, so the filter function is maintained for a long time. In addition, since static electricity is not generated temporarily, it is a permanent positive charge method, so it can be reused many times.
The newly developed filter was confirmed to block 98.3% of the 2.5 micrometers (㎛) size of particulates in the air. This is the N95 filter performance, a product currently on the market. In addition, the difference in breathing pressure before and after wearing the mask was measured as low as 59 Pascals (Pa), indicating good ventilation.
In addition, as a result of the waste decomposition test after use, it was biodegraded within 28 days in composted soil.
This research achievement was carried out as a major project of the Korea Research Institute of Chemical Technology of the Ministry of Science and ICT and a core industrial technology development project of the Ministry of Trade, Industry and Energy. It was published as a cover paper in the March issue of’Advanced Science’, an international academic journal.
In addition to filters, the research team is pursuing research that can replace all parts of the mask with biodegradable materials, such as a wire for fixing the nose bridge, a link to prevent loosening of the mask, and a rubber band.
Hwang Seong-yeon, director of the Korea Research Institute of Chemical Technology, said, “This technology is like an idea patent because it applied technology owned in Korea. I hope that many domestic companies can use it for commercialization in order to solve the plastic problem in the future.” There is still no dedicated landfill in Korea where biodegradable plastics can be buried in. Replacing masks with biodegradable materials is an intermediate process to a carbon-neutral society, and finally, a composting landfill that can effectively decompose them is systematically required. “He said.