Nanostructure Of Cellulose Acetate Membrane Studied By Electrochemical Impedance Spectroscopy

In recent year,water pollution has been more and more serious with the development of economy.In water treatment industry,membrane separation has been widely applied due to the low cost and high efficiency.The separation performance depends on the nanostructure of the membrane,i.e.,the water flux and solute rejection are related to the hole structure of the membrane.Thus,a series of cellulose acetate membranes with difference hole structures were fabricated using the phase-inversion method.Electrochemical impedance spectroscopy(EIS),scanning electron microscopy(SEM)and positron annihilation techniques were employed to characterize the membranes.The results show that a larger molecular weight or a higher content of the progen would lead to a higher water flux and lower pore resistance.A simple equation,that the water flux was found to be inversely proportional to the resistance obtained by EIS,was proposed based on the pore flow model,and the correlation has been proved by the experimental results.The relationship between the water flux data and EIS results implies that EIS could be a potential method for monitoring the microstructure of the membrane.The membrane would be polluted if it was used for a long time,which results in the decrease of life for the membrane..The titanium dioxide nanoparticles were introduced in the membrane,which improved the surface hydrophilicity and anti-fouling property of the composite membrane.