Personal protective equipment materials with high efficiency filtration and sterilization effect

Release time:

2019-06-17

Most of the air purification devices currently on the market rely on fiber mesh filter elements with a certain density and thickness. These filters exhibit excellent PM capture efficiency, but cannot achieve a killing effect on harmful microorganisms. With the continuous breeding of bacteria, fungi, viruses, etc., the service life of the filter will be greatly reduced. Therefore, it is particularly important to develop a green and environmentally friendly integrated air purification material that can filter out PM particles and sterilize.

The research team of Professor Wang Bo of Beijing Institute of Technology has prepared a series of metal-organic frameworks (MOFs) with photocatalytic activity in combination with previous research work, and screened ZIF-8 with ultra-high photocatalytic bactericidal activity to achieve efficient killing of Escherichia coli in water. Then, a new type of high efficiency integrated air filter (MOFilter) was designed and synthesized by hot pressing method. The PM particle capture efficiency can reach more than 98%, and at the same time, it can kill 99.99% of bacteria in the air.

Schematic diagram for integrated air purification and personal protection

The authors first compared a series of MOFs with photocatalytic activity, and the experimental results showed that the ZIF-8 was more than 99.9999% efficient in killing E. coli after 2 h of simulated sunlight irradiation. Through ICP-MS and photocatalytic sterilization experiments, it is verified that the excellent bactericidal performance of ZIF-8 mainly comes from the active oxygen free radicals produced by photocatalysis, rather than the release of Zn.²The bactericidal effect. At the same time, compared with the traditional photocatalytic sterilization semiconductor, the effect and rate of ZIF-8 photocatalytic sterilization are higher than that of ZnO and TiO.₂.

Photocatalytic bactericidal properties of ZIF-8

In order to simulate the real use environment, the author synthesized a ZIF-8-based MOFilter for filtering out PM particles and photocatalytic sterilization, and can achieve large-area preparation. The experimental results show that the PM filtration rate of MOFilter is as high as 98%. At the same time, the air sterilization rate of the MOFilter was more than 99.99% after being irradiated by simulated sunlight for 30 min. The used MOFilter were randomly cut out of 5 pieces, and cultured in liquid medium for 20 h, no recovery of bacterial growth was observed, further indicating that the MOFilter really achieved photocatalytic sterilization. More importantly, under the condition that the initial concentration of bacteria is 105CFU · mL-1, the sterilization rate of the MOFilter can be maintained at more than 99% after 5 times of continuous use, which lays the foundation for the commercialization of the material.

Characterization of MOFilter and comprehensive air purification properties

In order to realize the personal protection function, the research team developed a MOFilter-based personal protective equipment (MOFilter mask). The real use scenario was simulated by spraying microbial aerosol, and then the bacterial survival rate on the MOFilter mask was detected. No bacteria survived after 30min of light. At the same time and commercial N95 masks were compared, under the same conditions, commercial masks residual a large number of live bacteria. On the basis of the experimental results, the author also hot-pressed the ZIF-8 on the silk cloth for the preparation of self-cleaning clothing. This research has a very high application prospect in personal protection.