Study on the air filtration performance of nanofibrous membranes compared with conventional fibrous filters

Compared with conventional fibrous filters made of microfibers, the nanofibrous filters exhibit some special performances. Here, PVA nanofibrous membrane with thickness 28.37um was made by electrospinning 8% PVA solution on conventional cotton scaffold. The air filtration test system was built to test the filtration performance between PVA nanofibrous membrane and conventional fibrous filters which include meltblown PP nonwoven filter and common cotton filter with 12 layers. In experiments, the filtration efficiencies of particles distribution 0.3-5um were attained, at the same times, another important parameter, pressure-drops, were observed. Through data analysis, it is found that the pressure-drop of cotton filter is the least, while the filtration efficiency is the least. The meltblown nonwoven filter has higher filtration efficiency, but pressure-drop increases accordingly. The nanofibrous filter has the best efficiency, while the pressure-drop is beyond respirator request. In addition, SEM is used to observe the particles distribution in filter, from the SEMS images of filters, the different filtration mechanisms are analyzed and discussed. Finally it is found that the direct inception and the inertial impact get obvious as diameter of nanofiber decreasing rapidly, so filtration process mainly concentrates on the surface of PVA nanofibrous membrane, almost no particles distribute in cotton scaffold. Generally speaking, nanofibrous membranes are very promising and economic tools to enhance filtration performances of filters.