The Preparation And Properties Of Polyerhersulfone Ultrafiltration Membrane By Blending Modification

Membrane technology has a good development prospect in water treatment processes as a new separation method with high efficiency,and get much more attention.However,membrane technology is facing a series of problems,one of which is,hydrophilia deficiency caused by the membrane susceptible to pollution.The problem can increase cleaning frequencies,reduce membrane life time and further cause high costs.Therefore,improving the hydrophilicity and pollution resistance ability of membrane has becomethe most important research points at present.In this research,using nano silver ions-substituted hydroxyapatites(HAP/Ag)as modified material,and modified polyethersulfone(PES)ultrafiltration membrane by blending method to explore proper properation of adding materials;and the properties of the modified membrane were tested and represented.The main conclusions were listed as followings:(1)Firstly,the HAP/Ag was much similar to hydroxyapatite(HAP)in the structure,size,crystal structure and the characteristics of functional groups aspects,which proved the structure and properties of HAP materials were well maintained.(2)The water flux,rejection rate and contact angle of modified HAP/Ag materials were changed with different addition properation.Water flux increased to the peak value with a 2% addition properation,which improved by 397% compared with the original membrane flux.The rejection rate was 97% under a 5% addition value,which was much higher than that of the original membrane(64%).The contact angle decreased obviously by 19.27%,with a 3% dosage,and indicated good hydrophilicity for midified membrane compared with original membrane.Additionally,the elastic deformation and maximum tensile force of ultrafiltration membrane were increased significantly.(3)Tested results indicated antibacterial circle with different diameter sizes were arouded all the modified PES ultrafiltration membrane,the concentration of contact experiments further verified that with different addition properation of HAP/Ag,the antibacterial effectivenesses were different;the experiments of testing quantity and velocity of silver ion leaching revealed silver ions in the material were rapaidly dissolved at first stage and slowly released at later time.(4)The proper conditions of casting liquid were as followings through orthogonal experiments:18%,6% and 2% for PES,PVP and HAP/Ag,respectively,The pure water flux was 205.88 L·m-2·h-1,the rejection rate was up to 98.94% and the water flux attenuation coefficient was about 0.31 with good fouling resistance ability for modified PES ultrafiltration membrane after optimized.(5)The removal efficiency of COD and turbidity for modified PES membrane after optimized were 54.5% and 90.3%,which were increased by 1.20 times and 1.93 times,compared with unmodified PES membrane.All the PES membranes showed the same trend of resistance changing.The concentration polarization and membrane inherent resistances played the most important roles in the flux attenuation of ultrafiltration process among various resistances styles.The resistances of mmodified membrane after optimized design were continuously lower than unmodified membrane,indicating they were better in anti fouling performance.