Preparation And Properties Of PMIA Nanofiber Air Filter Material

The accelerating of industrialization and growth of population led to a serious air pollution.The air pollution can cause damage to human and lead to a series of diseases.Therefore,the development of high-performance air filtration materials which can be used for the treatment of polluted air has become one of the research hotspots.The traditional air filtration materials,such as spun lace,needle punching,and melt-blown nonwoven air filter materials,can only provide primary filtration of micron-level particles due to their coarse fiber diameter and large pore size.In order to obtain high filtration efficiency,the electret treatment is necessary.While the stability of electret effect is poor,so the application of the traditional air filter materials is limited.Moreover,most air filtration materials can only used at room temperature due to their poor thermal stability,hence the application of nonwoven air filter materials in the treatment of industrial high-temperature flue gases is limited.According to the previous research,the decrease of fiber diameter can effectively improve filtration performance,therefore,nanofiber air filtration materials（NAFMs）attract more and more attentions.As a common method for the preparation of nanofiber materials,the electrospinning process is simple and the fiber structure is easy to control.The nanofiber air filter materials which prepared by electrospinning technology has high efficiency and low resistance.Moreover,it is easy to develop multifunctional high-performance air filtration materials via adding inorganic nanoparticles to spinning solution.In this paper,PMIA which has excellent thermal stability is used as the polymer to prepare PMIA nanofiber air filter materials via electrospinning technology.Then barium titanate（BaTiO₃）and titanium dioxide（TiO₂）nanoparticles are added to the spinning solution for the enhancement of air filtration performance of PMIA nanofiber air filter materials.The main research contents are as follows:（1）Preparation of PMIA nanofiber membraneThe effects of spinning parameters（spinning time,spinning voltage,and spinning solution concentration）on the morphology,pore size and filtration performance were discussed.The results show that when the spinning time is 2 h,the voltage is 15 k V,and the mass fraction of PMIA solution is 12%,the prepared nanofiber membrane has a superior performance.When the speed of wind is 5.5 cm/s,the filtration efficiency of PM2.5 is87.5%,and the pressure drop is only 13.3 Pa.Moreover,the PMIA nanofiber membrane still maintains stable filtration performance under different wind speeds,particle concentrations,particle diameters,and operating time.（2）Preparation of PMIA/BaTiO₃ nanofiber membraneBased on the optimal parameters explored in the first part,PMIA/BaTiO₃ hybrid nanofiber membranes were prepared via electrospinning technology with different BaTiO₃nanoparticles addition.The effect of BaTiO₃ addition on the structure and properties of nanofiber membranes was explored.Furthermore,the thermal stability of PMIA/BaTiO₃nanofiber membranes was tested.The results showed that the PMIA/BaTiO₃ nanofiber membranes with 1 wt%BaTiO₃had a superior air filtration performance.When the speed of wind is 5.5 cm/s,the filtration efficiency of PM2.5 is 98.7%,and the pressure drop is only 60.4 Pa.The air filtration performance of PMIA/BaTiO₃ nanofiber membranes remained stable after treated at 250℃for 1h.The result indicated that the prepared PMIA/BaTiO₃ nanofiber membranes had excellent thermal stability.The prepared PMIA/BaTiO₃ nanofiber membranes had the potential application in the field of high temperature flue gas dust removal.（3）Preparation of PMIA/TiO₂ nanofiber membraneBased on the optimal parameters explored in the first part,PMIA/TiO₂ nanofiber membranes were prepared via electrospinning technology with different TiO₂ nanoparticles addition.The effect of TiO₂ addition on the structure and properties of nanofiber membranes was explored.The results showed that:When the additional amount of TiO₂ was 5 wt%,PMIA/TiO₂ nanofiber membranes showed superior air filtration performance.When the wind speed was 5.5 cm/s,the filtration efficiency of PM2.5 reached up to 99.4%,while the pressure drop was only 61 Pa.The air filtration performance of PMIA/TiO₂ nanofiber membranes remained stable after treated at 250℃for 1h.The result indicated that the prepared PMIA/TiO₂ nanofiber membranes had excellent thermal stability.