Preparation of hollow fiber membrane via grafting tannic acid and its influence on microstructure, permeability and anti-fouling

Polyvinylidene fluoride/polyamide6-grafting-tannic acid (PVDF/PA6-g-TA) hollow fiber membrane was prepared via the reaction between TA and PA6 on the membrane surface by thermally induced phase separation (TIPS) technique. The reaction mechanism and the distribution for TA on outer surface were explored. The change of surface morphology, hydrophilicity, chargeability, anti-fouling capacity and permeability was investigated after grafting. It was found that Schiff base reaction occurred between amino group and phenolic hydroxyl group, and thus avoided the falling of TA. The uniform distribution of TA on outer surface enhanced the hydrophilicity, rejection and anti-fouling capacity. Finally, the improvement of anti-fouling capacity and permeability was analyzed from chargeability for TA and bond water layer on repulsing the stackage of the pollutants. This work provides an efficient way to enhance the anti-fouling performance of membrane via TIPS.