Polyphenol/Fe^III Complex Coated Membranes Having Multifunctional Properties Prepared by a One-Step Fast Assembly

The membrane filtration process has received much attention as one of the most promising water purification techniques. However, it still has several disadvantages, such as organic-, oil-, and biofouling, membrane contamination by microorganisms, and the difficulty in rejecting heavy metal ions, which are closely related to the membrane surface properties. Various approaches have been used to prepare membranes with antifouling, antimicrobial, or heavy metal ion removal properties on their surfaces. However, membranes with all these properties have not yet been reported. It might be possible to prepare membranes with such multifunctional properties by modifying the membrane surfaces with various organic and/or inorganic functional materials using multiple chemical/physical modification procedures, though the process should be very tedious, costly, and time consuming. Here, a multifunctional filtration membrane is prepared by a rapid one-step assembly coating of tannic acid and iron ion (Fe^III) on a commercial poly(ether sulfone) membrane. The catechol- and gallol-rich surfaces combine all of the desirable properties such as antifouling against proteins, oils, and microorganisms, as well as antimicrobial and heavy metal ion removal properties. This study provides a facile approach to prepare multifunctional filtration membranes that have potential applications in practical water purification.