High-flux, anti-fouling dendrimer grafted PAN membrane: Fabrication, performance and mechanisms

Polyamidoamine (PAMAM) dendrimers grafted Polyacrylonitrile (PAN) UF membrane (PAN-PAMAM) was prepared for the first time. 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 hydmphilicity, the membrane was further modified with ethanolamine (ETA) under different conditions. The results suggest that PAN-PAMAM membrane modified by ETA/NaOH has an improved antifouling property for sodium alginate (SA), humic acid (HA) and bovine serum albumin (BSA), the flux recover ratio (FRR) increased from 61% to above 91%. Moreover, the modified membrane shows 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, leading to an improved antifouling property. Surface tension and XDLVO theory were further used to analyze the fouling process. It was found that ETA/NaOH modification greatly increases the Lewis acid-base interfacial interaction of membrane. However, after the adsorption of BSA, Lewis acid-base interaction decreases greatly, leading to the irreversible fouling of membrane.