Preparation And Property Of Electrospun Nanofibrous Membrane For Air Filtration

Air filter materials were usually used to protect people from serious air pollution.Their filtration property affects directly the ability of the materials to protect people from being attacked by the particulate matters.There are some difficulties for conventional non-woven filter materials to meet the requirement of filtering PM_2.5.5 because they usually have large pores formed by the microscale fibers.Recently,preparation of nanofibrous filtering materials becomes hot in academic area and is paid much attention in industry,with some popular product in daily life.In this thesis,electrospun nanofibrous membranes for air filtration were fabricated and their structure,morphology and filtration properties were investigated.?1?Nanofibrous membranes were fabricated by electrospinning using PAN as raw material with DMF as solvent.Scanning electron microscope was adopted to observe the structure and morphology of the electrospun PAN.Image software was used to analyze the diameter as well as the diameter distribution of the membrane fibers.Home-made setup was used to test the filtration efficiency of the electrospun PAN membranes.The relationships between the parameters such as the concentration of PAN,voltage used,collecting distance,flow rate and the membrane properties such as structure,morphology and filtration efficiency were investigated.The results showed that when the concentration of PAN was 6wt%,the voltage was 16 Kv,the flow rate was 0.5 mL/h and the collecting distance was 12 cm,the obtained diameter of the fiber is much smaller reaching84.61 nm.When the electrospinning time was 5 h,making membrane thickness of 102?m,the filtration efficiency of the film was 98.5%.?2?PM_2.5.5 in the polluted air usually contains a high level of moisture in the atmosphere,which can be utilized to adjust the membrane property.The PAN/PVP composite membranes were obtained by electrospinning PAN with PVP added to increase the polarity of the materials.The effects of PVP and the amount of PVP added on the diameter,morphology,the wetting property of the membrane and the filtration efficiency were investigated.The results showed when the concentration of the PVP was 12%of PAN,the CA of the membrane was 14.7°,the filtration efficiency was excellently to be 99.2%.In summary,materials with excellent filtration property can be fabricated from PAN and their filtration efficiency can be improved by increasing the polarity of the membrane.