Study On Fabrication And Mechanisms Of High-flux And Anti-fouling Dendrimer Grafted PAN Membrane

In this paper,polyamidoamine(PAMAM)dendrimers grafted Polyacrylonitrile(PAN)OF membrane(PAN-PAMAM)was prepared by in-situ modification for the first time.On this basis,PAN-PAM AM membrane was further optimized through surface modification,and the modified samples were characterized by means of scanning electron microscopy(SEM),infrared spectroscopy(ATR),X-ray photoelectron spectroscopy(XPS)and thermogravimetric(TGA).Firstly,PAN-PAMAM casting solution with different proportions were prepared,and then heated for reaction.Finally PAN-PAMAM membranes were prepared by NIPS method.By comparing the structure and performance of the obtained membranes,the optimal preparation concentrations were set as 15 wt.%PAN and 0.5 wt.%PAMAM.The optimized PAN-PAMAM membrane showed both a high flux(420 L·m-2·h-1·bar-1)and a good BSA rejection(99%).To improve its hydrophilicity,ETA was used to modify PAN-PAMAM membrane.The flux of ETA/N aOH modified membrane decreased less(403 L·m-2·h-1·bar-1)and the BSA rejection remained at 98%.XPS spectra revealed that C(O)=O groups formed on the surface of ETA/NaOH modified membrane,leading to the improved hydrophilicity.The modified membrane had an improved antifouling property for SA,HA and BSA.The FRR for BSA/PBS increased from 61%to above 91%,and for both HA and S A increased to above 93%.Moreover,the modified membrane showed a better antifouling property in phosphate-buffered saline(PBS)solution than in water solution.DLS results showed that BSA aggregate morphology are different in two solutions.AFM image and BSA adsorption revealed that PBS decreases the coverage and amount of BSA adsorbed on the membrane surface.The BSA adsorption capacity of the ETA/NaOH modified membrane in BSA/PBS solution was only 18 ?g/cm2.Surface tension and XDLVO theory were further used to analyze the fouling process.It was found that?GXDLVO changed from negative to positive after ETA/NaOH modification,which mean the modified membrane showed a strong repulsion to BSA.And ETA/NaOH modification greatly increased the Lewis acid-base interfacial interaction of membrane,which was favorable for the desorption of BSA.However,after the adsorption of BSA,Lewis acid-base interaction decreased greatly,leading to the irreversible fouling of membrane.