Surface modification of Fe^Ⅲ-juglone coating on nanofiltration membranes for efficient biofouling mitigation

Nanofiltration membranes have increasingly played a vital role in the purification of surface water and the recycling of wastewater. However, the problem of membrane biofouling, which leads to shortened service life and increased energy consumption, has hindered the widespread application of nanofiltration membranes. In this study, we developed functionalized nanofiltration membranes with anti-adhesive and anti-biofouling properties by coordinating Fe^III and juglone onto commercial nanofiltration membranes in a facile and viable manner. Due to the hydrophilic nature of the Fe^Ⅲ-juglone coating as well as its ultra-thin thickness and minimal impact on the membrane pores, the permeance of the optimally modified membrane even increased slightly (14 %). The outstanding anti-adhesive property of the Fe^Ⅲ-juglone coating was demonstrated by a significant reduction in the adsorption of proteins and bacteria. Furthermore, the modified membranes exhibited lower flux decline amplitude and reduced biofilm deposition during dynamic fouling experiment, further supporting the outstanding anti-biofouling performance of the nanofiltration membrane after the modification with Fe^Ⅲ-juglone coating. This study presents a novel and feasible approach for simultaneously improving the water permeance, anti-adhesive property and anti-biofouling property of commercial nanofiltration membranes.