Fabrication And Filtration Performance Of Ultra-fine Polyethersulfone Nanofibrous Membranes

Electrospun nanofibrous membranes exhibited great advantages such as high porosity,high surface area,and adjustable pore geometry over conventional membranes.Multi-functional nanofibrous membranes fabricated by electrospinning technology can simultaneously remove nanoparticles by screening filtration and remove charged species,e.g.,dyes and heavy metal ions,by adsorption simultaneously,which could be employed for the treatment of multi-contaminant sewage water.Two different approaches were employed to fabricate functional sulfonated polyethersulfone(SPES)nanofibrous membrane:(1)Electrospun PES nanofibrous membranes followed by surface sulfonation;(2)Electrospun sulfonated PES with different sulfonated degrees directly to prepare functional nanofibrous membranes.Consequently,electrospun SPES membrane with ultra-fine mean fiber diameter,e.g.,62±16 nm,were fabricated by two-nozzle electrospinning approach and employed as a multi-functional membrane for removal of nanoparticles,dyes,heavy metal ions from multi-contaminant sewage through filtration and adsorption simultaneously.The pore size and pore size distribution of the membrane could be-varied and adjusted by controlling the fiber diameter,which affect on the filtration retention of nanoparticles;while the sulfonic groups located on the surface of the nanofibers work as active sites for the adsorption of dyes and heavy metal ions by electrostatic interaction.Increase in degree of sulfonation and decrease in concentration of solution led to the reduction of fiber diameter of the electrospun nanofibrous membranes,evidenced by SEM and TEM measurements,in addition to the increase in the molecular weight of SPES.The adsorption kinetics and thermodynamics of the nanofibrous membrane for dye and heavy metal ions were investigated separately,as well as the filtration performance of nanoparticle suspensions.The ultra-fine nanofibrous SPES membrane was challenged finally with multi-contaminant model sewage containing 0.2?m-particles,methylene blue,and Pb(?)ions,where high permeation flux of 240 L/m2h,high retention of 99.0%,and low pressure drop of 0.02 MPa were achieved in the filtration performance.