Evaluating the anti-fouling property of the hydrophilically modified porous PTFE membrane

Abstract

The flat sheet PTFE membrane was modified into hydrophilicity via deposition of fluorinated cationic surfactant. The anti-fouling property of the membranes was investigated using lysozyme (LYS) and humic acid (HA) as typical foulants and further evaluated by Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. The results indicated that the wettability of the PTFE membrane can be manipulated by concentration of surfactant solution, and the super hydrophilic membrane with water contact angle of 2.1° was obtained with 0.8 wt% of surfactant solution. The super hydrophilic PTFE membrane showed highest cleaning efficiency of 62.5% and better anti-fouling property. XDLVO analysis further suggested that the super hydrophilic PTFE membrane had the strong repulsion force to HA and LYS and displayed better anti-fouling property due to the highest positive total interaction energy (ΔGTOT) value. Linearly fitting on membrane practical fouling process and XDLVO results proved the consistency of the XDLVO theory with the practical anti-fouling process.