Preparation Of Bio-based Electrospun Nanofiber Membranes And The Application In Air Filtration

Air particulate pollution from ever-increasing industrialization poses an enormous threat to public health.Thus,the development of air filter with high efficiency and performance is of urgent necessity.The nanofiber membrane prepared by electrospinning technology has the advantages of controllable fiber diameter,high porosity and large specific surface area,which can achieve high filtration efficiency at low pressure drop,and may become the most attractive air filtration material.Although most electrospun nanofiber membranes have excellent filtration performance for fine particles,the production of secondary pollution after use will substantially limit their practical applications.Moreover,in the field of personal protection,nanofiber membrane is further required to have good biocompatibility and non-toxicity.Considering the huge challenges brought by environmental pollution and health problems.In this paper,a series of composite nanofiber membranes with high efficiency were prepared from water-soluble polymers and bio-based small molecular materials using a green environmental protection method.The research works and results are in detailed as follows:（1）An environmentally friendly PVA-LS high-efficiency filter was prepared for the first time by combining green electrospinning and physical crosslinking technologies.The mechanical properties,filtration performances and transparency of nanofiber membrane were studied.Compared to a pure PVA nanofiber membrane,the tensile strength and elongation at break of the PVA-LS composite nanofiber membrane were increased by 165%and 419%,respectively,due to the hydrogen bonding between PVA and LS.In addition,the composite nanofiber membrane exhibited a large QF of 0.212 Pa^-1,a low pressure drop of 24.5 Pa,as well as a high filtration efficiency of 99.44%.After 10 filtration cycles,the obtained air filter still exhibited a high filtration efficiency（99.38%）and a low pressure drop（25.5 Pa）.In addition,when the filtration efficiency of PVA-LS nanofiber membrane is more than99%,the transmittance can reach 78%,showing excellent transparency.（2）We have prepared an environmentally friendly PVA-TA nanofiber membrane for air filtration by combining electrospinning and hydrogen bond crosslinking technology.Due to the hydrogen bonding between TA and PVA,the tensile strength and elongation of PVA-TA nanofiber membrane were increased by 57%and 152%respectively.In addition,the removal efficiency of PM_1.0 of PVA-TA air filter can reached 99.5%when the pressure drop was only 35 Pa,and the quality factor can reached 0.15 Pa^-1,showing excellent comprehensive filtration performance.In the durability test,the filter still showed a filtration efficiency higher than 99%and a low pressure drop of 35.5 Pa after ten cycles of filtration.（3）Finally,the filtration performance of the composite nanofiber membranes was compared with the commercial mask.We found that the mask with composite nanofiber membranes as the core layer had excellent filtration performance and reusability,avoiding environmental pollution caused by a large number of discarded masks.We expect that this research will provide valuable insight for the preparation of environmentally friendly filter,and provide protection for people in the outdoor environment.