Ethyl Lauroyl Arginate as a Solution for Membrane Biofouling in Drinking Water Desalination Systems: A Lab-Scale Study

Reverse osmosis (RO) membrane technology may offer a promising solution to address global water scarcity; however, biofouling remains a critical technical limitation that impairs system performance and increases operational costs. Current biofouling mitigation methods, such as chlorine-based feedwater pretreatment, fail to provide sustainable long-term solutions, highlighting the need for more effective preventive strategies. In this study, the antibiofouling properties of ethyl lauroyl arginate (LAE) and its long-term compatibility with RO membranes are examined. Minimum biofilm inhibitory concentrations (MBICs) were determined using 96-well plate assays, while a CDC Biofilm Reactor was used to evaluate LAE’s antibiofilm efficacy against single-species (Staphylococcus aureus) and multispecies biofilms (Rhizorabdus wittichii and Staphylococcus aureus). A one-month degradation test assessed membrane compatibility. Membrane autopsies were conducted for both antibiofouling and compatibility experiments. Scanning electron microscopy (SEM) and confocal laser scanning microscopy were used to assess antibiofouling efficacy, whereas SEM, attenuated total reflectance Fourier-transform infrared spectroscopy, and atomic force microscopy assessed membrane degradation. Results showed that LAE caused no significant membrane damage under the tested conditions (pH 6–8; 1-month exposure; 12× MBIC) and achieved over 99% biofilm inhibition at 50 mg/L, showing its potential as a promising solution to address membrane biofouling in desalination systems.