Antifouling and antimicrobial modification of polyvinylidene fluoride micropore membrane by plant tannic acid and polyhexamethylene guanidine

Abstract

With the industry's rapid development, the treatment of wastewater has aroused great concern. The separating membrane is a significant tool for water purification, however, bacterial contamination has seriously affected the service life and separation effect of the separation membrane. Polyhexamethylene guanidine (PHMG) is an effective environmentally-friendly antimicrobial modifier. Tannic Acid (TA) as an antibacterial and hydrophilic modifier, has an excellent fixation effect on the PHMG coating. In this study, PHMG was used to coat the pristine polyvinylidene fluoride (PVDF) micropore membrane. Then, the PHMG/TA composite modified membrane was fabricated via TA immobilization. The surface morphology and chemical structure of the membranes were analyzed by FESEM, AFM, EDS, ATR-FTIR, and XPS. The antifouling and separating performance were characterized via the pure water flux recovery rate after emulsion test and emulsion reject rate. The emulsion reject rate could reach 99.99%, and pure water flux recovery rate could also reach at least 90%. The colony-forming unit (CFU) test was carried out to analyze the antimicrobial activity of the modified membranes against Bacillus subtilis and Escherichia coli. The results indicated that the surface modification of PHMG and TA endowed the PVDF micropore membrane with excellent antifouling and antibacterial properties.