Effective Biofouling Control of Reverse Osmosis Membranes via Plant Extract Coating

Abstract

Biofouling as a main challenge in reverse osmosis (RO) membranes has been attempted to mitigate by surface modification of membranes via synthetic chemicals. However, the use of plant-based materials as anlternative green approach has gained specific attention due to its environmentality bengin and cost-effectiveness. Herein, a green method has been introduced to sustainably engineer RO membrane surface utilizing leaf-extract powders of Lawsonia inermis and Isatis tinctoria to reduce their biofoiling propensity and improve cleaning effectiveness. The resultant surface modification significantly enhanced membrane surface hydrophilicity, while retaining high salt rejection performance and water flux. Furthermore, upon biofouling analyses of membranes against bacterial solution, the Lawsonia inermis-coated membrane showed the lowest flux decline and the highest flux recovery rate. As hypothesized, this can be attributed to the improved hydrophilicity and our experimentally proven antibacterial activity of the biomass. This study illustrates plant-extract-based surface modification as an economical, environmentally friendly, and promising method of enhancing the antifouling properties of RO membranes, even under relatively higher operating pressures.