Meltblown fabric vs nanofiber membrane, which is better for fabricating personal protective equipments

The coronavirus disease 2019(COVID-19)pandemic has led to a great demand on the personal protection products such as reusable masks.As a key raw material for masks,meltblown fabrics play an important role in rejection of aerosols.However,the electrostatic dominated aerosol rejection mechanism of meltblown fabrics prevents the mask from maintaining the desired protective effect after the static charge degradation.Herein,novel reusable masks with high aerosols rejection efficiency were fabricated by the introduction of spider-web bionic nanofiber membrane(nano cobweb-biomimetic membrane).The reuse stability of meltblown and nanofiber membrane mask was separately evaluated by infiltrating water,75%alcohol solution,and exposing under ultraviolet(UV)light.After the water immersion test,the filtration efficiency of meltblown mask was decreased to about 79%,while the nanofiber membrane was maintained at 99%.The same phenomenon could be observed after the 75%alcohol treatment,a high filtration efficiency of 99%was maintained in nanofiber membrane,but obvious negative effect was observed in meltblown mask,which decreased to about 50%.In addition,after long-term expose under UV light,no filtration efficiency decrease was observed in nanofiber membrane,which provide a suitable way to disinfect the potential carried virus.This work successfully achieved the daily disinfection and reuse of masks,which effectively alleviate the shortage of masks during this special period.

Effects of operating conditions on membrane charge property and nanofiltration

The effects of the operating pressure,crossflow velocity,feed concentration,and temperature on the streaming and Zeta potential of the membranes were studied.The permeateflux and the retention rate under different nanofiltration operating conditions were also investigated.The results show that the higher pressure,feed concentration,temperature,and lower crossflow velocity lead to the higher absolute value of streaming and Zeta potential.The permeateflux of the nanofiltration decreases with the feed concentration and increases with not only the pressure but also the crossflow velocity and temperature.The higher the pressure and the crossflow velocity,the higher the retention rate.The lower feed concentration and higher temperature leads to lower retention rate.The effects of the operating conditions on the permeateflux and the retention rate were explained by the variation of the membrane charge property.