Surface modification of PAN hollow fiber membrane by chemical reaction

In this study, a new method was applied to achieve an efficient surface modification of Polyacrylonitrile (PAN) hollow fiber membrane. The surface modification dealt by immersion of PAN hollow fibers in hydroxylamine solution under various conditions (different solution concentrations and reaction time). The nitrile groups on the surface of the membrane were changed to form the amidoxime (-C(NH2)=N-OH) groups. The surface modified membranes were assessed by pure water permeation test and the rejection of high molecular weight materials like Polyvinylalcohol (PVA) from water. Permeation test results showed that with increasing hydroxylamine concentration, the amount of water permeation reduces slowly, while the PVA-30 kDa rejection has been somewhat increased after surface modification. FTIR/ATR analysis confirms the presence of amidoxime groups on the membrane surface. Also, the water contact angel was decreased from 64 to 34 after reaction. The ability of silver ions absorption was also assessed for modified membrane. Finally, the antifouling property of the modified hollow fibers was assessed by milk solution ultrafiltration. The obtained results showed that the modified hollow fibers present better antifouling properties.