Hydrophilic modification of polytetrafluoroethylene flat membranes coated by acrylic acid water-absorbent resin

Abstract

To improve hydrophilicity and anti-fouling property of the polytetrafluoroethylene (PTFE) flat microfiltration (MF) membrane, a facile method was developed to modify the membrane via the post-cross-linking reaction of polyacrylic acid (PAA) and trimethylolpropane tris-(2-methyl-1-aziri-dinepropionate) (Sac-100) followed by soaking NaHCO3 saturated solution. The surface chemical composition, surface morphology, hydrophilicity and filtration performance of the PTFE flat membrane were examined by XPS, ATR-FTIR, FESEM, water contact angle and pure water flux measurements, respectively. The results showed the hydrophilic groups such as carbonyl (C=O), hydroxyl (−OH) and carboxylic ion (−COO–) were observed on the surface of modified membrane, it can be seen as a water-absorbent resin system. After choosing this low-cost and simple modification method, the PTFE flat membrane was endowed with excellent hydrophilicity, high water permeation flux. Then, effects of surface modified conditions on membrane hydrophily were studied systematically. The anti-fouling tests were conducted using the modified PTFE flat membranes, results showed the modified PTFE flat membranes possess excellent bovine serum albumin (BSA) fouling resistance. Finally, the surface stability of the modified membrane was studied and the modified membranes showed stability under the acidic condition but weak to strong alkali. Therefore, this facile strategy holds attractive potential practical application in water environmental remediation, for example, treatment of medical wastewater.