Controllable Preparation And Characterization Of Cellulose Nanofibers Based Air Filter Materials

With the large-scale use of petrochemical fuels,the air pollution has become a serious problem in China.As is know to all,excessive PM2.5 in the air is threatening the health of people and excerting a negative effect on living conditions of all.Therefore,people are becoming more and more aware of the problem,and the development of air filtration has received more and more attention and effort.Typically,the preparation of air filtration materials requires the use of lots of harmful solvents or raw materials.Environment friendly preparation of air filtration is necessary.In this study,cellulose nanofibers/vinyltrimethoxysilane(CNFs/VTMS)porous materials with network-like porous structure were prepared.By studying the effect of varying silane content,initial concentration of CNFs and preparation temperature,it was found that when the concentration of CNFs was 2.5 wt%,the CNFs:VTMS ratio 1:6,and the temperature-80°C,the CNFs/VTMS porous materials'prepared had a air filtration efficiency of 99.6%for 0.3?m nanoparticles,and pressure drop of 310 Pa.The material also had good mechanical properties,could be used in a hot and humid environment of 200°C without affecting losing its performance.However,when the concentration of CNFs is lower than 1.5 wt%,the prepared CNFs/VTMS porous materials has poor filtration efficiency.In order to improve such a situation,subsequent research was conducted.Nano-structure spherical calcium-magnesium-silicate(SCM)particles were prepared by using water glass,magnesium chloride and calcium chloride.By studying the effects of salt solution concentration,salt solution ratio,water glass solution concentration and organic solvent impregnation on the specific surface area of resulting particles,it was found that at the concentration of salt solution of 1.5 mol/L,the ratio of calcium to magnesium salt of 65:35,the concentration of water glass solution of 1.5 mol/L,and impregnated with n-hexane,the specific surface area of SCM could be as high as 446.83 m~2/g.Then a CNFs/VTMS/SCM composite porous material with good pore structure was prepared by direct blending method.The nano SCM was deposited on the surface of the cellulose nanowires.It was demonstrated that the air filtration performance,mechanical properties,and specific surface area of the composites were improved upon addition of SCM nano particles,while no obvious pressure increased was observed.