Linoleic acid, a plant fatty acid, controls membrane biofouling via inhibition of biofilm formation

Biofouling of reverse osmosis (RO) membranes increases the operation cost of the seawater desalination process, by reducing salt rejection and increasing permeation pressure. However, biocides commonly used to inhibit biofouling not only increase bacterial resistance, but also damage the chemical structure of the RO membrane due to oxidation. Linoleic acid (LA), a polyunsaturated fatty acid, inhibits biofilm formation by Pseudomonas aeruginosa, without affecting bacterial growth. After treatment with LA, the volume and thickness of biofilm on the RO membrane decreased by 47% and 33%, respectively, without affecting the morphology and chemical structure of the RO membranes. Based on these results, LA was applied to control the biofouling in a laboratory-scale RO system. Upon treatment with LA, a loose and porous biofilm formed on the RO membrane, which demonstrated increased membrane performance and water permeability when compared with untreated system. These results suggest that LA can be used as a biofouling inhibitor in RO processes.