Improving antifouling and antimicrobial performance of reverse osmosis membrane by incorporating iodophoric polyvinylpyrrolidone coatings

Reverse osmosis (RO) membrane with antifouling and antimicrobial performance was developed by incorporating iodophoric polyvinylpyrrolidone (PVP) coatings assisted with polydopamine (PDA). The membrane surface was coated with PDA layer through self-polymerization of DA, followed by the adhesion of hydrophilic PVP onto the coated surface via strong multiple hydrogen bonding facilitated by catechol in PDA. Iodine was introduced through complexation with PVP. The modified membrane demonstrated enhanced hydrophilicity and increased surface roughness, while exhibiting a reduction in surface negative charge. Water flux of the modified membrane remained unchanged, while the high NaCl rejection was successfully maintained and stabilized at above 99.0%. Meanwhile, modified membrane exhibited outstanding performance stability and satisfactory pH stability. Moreover, during fouling experiments with bovine serum albumin and lysozyme as model foulants, the membrane demonstrated a lower decline in flux rate and a higher recovery rate. Besides, modified membrane exhibited excellent anti-biofouling performance after soaking in bacterial suspension. Furthermore, after being in contact with the surface of membranes freshly prepared or soaked in deionized water for 4 months, E. coli and B. subtilis showed a mortality rate exceeding 99%. This study introduces an efficient strategy for preparing antifouling and bactericidal RO membranes without sacrificing their intrinsic desalination performance.