Preparation And Filtration Performance Research On PA6 Nanofibrous Laminated Membranes

With the rising speed of scientific development and modern industrialization,filter materials have been widely applied in the fields of air purification,wastewater treatment,individual protection and health care.Although the traditional filtration materials have good filtration efficiency for the particles above the micron level,they can not effectively intercept the sub-micron grade particles,which cannot meet the requirements of high efficiency filtration.Therefore,it is urgent to develop a new and functional efficient filtration material.Nanofiber materials have unique structure,function,properties and extensive application prospect.And electro spinning is a method of preparing ultra-fine fibers of nano-scale to micro-scale.The electrostatic spinning nanofiber material with three-dimensional spatial structure has the advantages of small diameter,large specific surface area,high porosity,small pore diameter and good continuity of fibers,and therefore is widely used in many fields such as gas filtering,liquid filtration and individual protection.In this paper,PA6 with good spinnability and chemical stability was selected as the electrostatic spinning polymer.The effects of polymer concentration,solvent ratio,spinning parameters and hot-pressing process on the microstructure,specific surface area,pore size and filtration properties of the fiber membrane were studied.Finally,it was determined that the optimal spinning solution was a PA6 polymer dissolved in a mixed solvent of 10wt%formic acid/glacial acetic acid with a mass ratio of 1/1,and a PA6 nanofiber membrane was prepared by adjusting the spinning parameters.The structure and properties of PA6 nanofiber membrane were characterize by scanning electron microscope and comprehensive testing bench for filter material.The filtration efficiency of ultra-fine sodium chloride aerosol particles with size of 0.3?m can reach 99.28%,and the filtration pressure resistance was less than 120 Pa.The composite PA6 nanofiber laminated membrane was obtained through the treatment of hot pressing process.By means of scanning electron microscope,specific surface and pore size analyzer,it showed that the composite PA6 nanofiber laminated membrane had better microstructure and pore structure.And then an indigo dye solution of 10mg/L was filter by the flat membrane dead-end filtration device,which was constructed by ourselves.It was showed that the composite nanofiber membrane can effectively intercept the indigo dye molecules in indigo dye solution on the membrane surface and inside,and after filtration for 500 min,the filtration flux was still maintained above 15 L·m-2·h-1.