Preparation And Performance Study Of High-efficiency PP-PC/PVDF/ZIF-8 Bark-like Meltblown Electrospinning PM_2.5 Air Filter Material

With the rapid development of global industrialization,the problem of air pollution is becoming increasingly serious,especially fine particulate matter with aerodynamic diameter below or equal to 2.5?m in the air(PM_2.5)can carry toxic and harmful substances such as heavy metals,polycyclic aromatic hydrocarbons.Light can cause respiratory system infection,heavy can cause lung cancer,cerebrovascular and other diseases.Therefore,the development of terminal high-efficiency air fiber filter has become an important breakthrough to reduce PM_2.5 damage to human body.Among many air filters,electret fiber filter can rely on electrostatic power to capture PM_2.5 without increasing pressure drop,so it is the most efficient and low resistance air filter.However,it has the fatal disadvantage that the charge dissipates rapidly when wet.In addition,the air filter prepared by meltblown technology has the advantages of high porosity,wide filter channels,low pressure drop and high yield.However,the micron fiber scale restricts its further improvement in filtration performance.In view of this,in this paper,a high efficiency and low resistance barklike meltblown electrospinning composite membrane with excellent filtration stability is prepared in three parts.The main research results obtained are as follows:?1?Refine the fiber diameter of the meltblown membrane to nanoscale,and the surface of the fiber has barklike grooves.Prepared a barklike PPC meltblown membrane with an average fiber diameter of nanoscale under one-step method due to the incompatibility and viscosity difference of both polypropylene?PP?and polycarbonate?PC?polymers.Moreover,the electret PC can act as a nucleating agent for PP that significantly increase the surface potential value of the membrane.The PPC-3 membrane with 97%PP/3%PC ratio has the best filtration performance.The PM_2.5filtration efficiency and the quality factor respectively are 71.03%and 0.0269 Pa^-1,which are 81.57%and 63.03%higher than PP membrane with 39.12%and 0.0165 Pa^-1,respectively.The pressure drop of PPC-3 membrane is 46 Pa.?2?Preparation of a high efficiency and low resistance barklike meltblown membrane with stable filtration performance after encounter water.Based on the first part of the research,a novel in-situ growth method was used to combine PPC membrane with zeolitic imidazolate framework ZIF-8 that has high specific surface area,great thermal and chemical stability to prepare PPC/ZIF8-9 barklike composite membrane.The resultant membrane effectively improved the filtration efficiency without increasing the pressure drop value.Its PM_2.5 filtration efficiency and quality factor respectively are 91.68%and 0.0553 Pa-1,which are 29.07%and 105.58%higher than the PPC-3 membrane,respectively.Furthermore,the membrane still has excellent filtration performance after fifth filtration-wash-dry cycles.?3?To further improve the filtration performance of the PPC/ZIF8-9 membrane prepared in the second part.PPC/ZIF8-9 membrane and PVDF/ZIF-8 electrospinning membrane were combined to prepare PPC/PVDF/ZIF-8 barklike meltblown electrospinning composite membrane.Among them,the PPC/PVDF/ZIF8-2 membrane with 0.2%ZIF-8/7.8%PVDF/92%DMF electrostatic spinning solution has the best filtration performance.Its PM_2.5 filtration efficiency and quality factor respectively are99.82%and 0.1236 Pa^-1,which respectively are 8.88%and 123.51%higher than PPC/ZIF8-9 membrane,the pressure drop is only 51 Pa,and the filtration performance is still at a high level of 98.03%after fifth filtration-wash-dry cycles.In addition,the surface potential of PPC/PVDF/ZIF8-2 membrane increased from-1011.2 V of PPC/ZIF8-9 membrane to-2709 V.In summary,compared with pure PP membrane,the filtration efficiency,quality factor and surface potential of PPC/PVDF/ZIF8-2 barklike meltblown electrospinning composite membrane in this paper respectively improved 155.15%,649.09%and1685.76%under same process conditions,and the pressure drop only increased by 21Pa.This membrane has outstanding filtration performance among high-efficiency air filters,which is expected to provide new ideas for the development of high efficiency and low resistance PM_2.5 air filter with excellent filtration stability after encounter water.