Development of modified reverse osmosis membrane with polymers/graphene oxide for scaling and biofouling mitigation

Abstract

The increasing demand for freshwater, coupled with challenges posed by industrialization and climate change, has reinforced the need for efficient desalination technologies. Reverse osmosis (RO) is widely used due to its energy efficiency; however, operational challenges such as scaling and biofouling hinder membrane performance, reducing water flux and increasing maintenance costs. This study uniquely explored, for the first time, the dual antifouling and antibiofouling properties of polymaleic acid (PMA) in an RO system. PMA-modified membranes exhibited superior antifouling properties. During gypsum scaling experiments, the PMA-coated membrane (ESPA2-PMA) exhibited a 26.6% flux decline compared to 15.2% for the unmodified ESPA2, while PMA in solution further reduced flux decline to just 6%. This performance is attributed to PMA's ability to disrupt crystal growth and alter gypsum morphology, as confirmed by SEM and XPS analyses. In biofouling experiments, PMA coatings decreased biofilm coverage significantly, with ESPA2-PMA reducing Vibrio fischeri biofilm growth by 40% compared to unmodified membranes. The addition of GO into the PMA matrix further enhanced biofilm resistance, reducing biofilm formation by over 60%. Notably, this is the first study to demonstrate the antibacterial and antibiofouling efficacy of PMA in an RO system, establishing PMA as a multifunctional agent for membrane protection. The PMA-GO nanocomposite coatings also maintained high water permeability (2.6 L/m2·h·bar), exceeding the performance of the unmodified ESPA2 membrane (1.4 L/m2·h·bar). This comprehensive evaluation of PMA and GO as both coating agents and solution additives underscores their synergistic potential for scaling and biofouling mitigation in RO systems. The findings highlight PMA-GO nanocomposite coatings as a sustainable and innovative solution for improving membrane performance, offering reduced operational costs and enhanced durability.