Advances in Membrane Technologies for Seawater Desalination: Carbon- and Metal-Based Nanocomposites for Fouling Mitigation

Abstract

Membrane-based desalination technologies, particularly reverse osmosis (RO) and multieffect distillation (MED), are critical for addressing global water scarcity but face challenges from membrane fouling, which reduces efficiency and increases operational costs. This review examines advancements in fouling mitigation through carbon- and metal-based nanocomposite membranes. Carbon nanomaterials, such as graphene oxide (GO) and carbon nanotubes (CNTs), enhance hydrophilicity, mechanical strength, and antimicrobial activity, significantly reducing biofouling and scaling. Functionalized GO composites demonstrate high chlorine resistance and improved water flux, while CNT and metallic nanoparticle–polymer blends forming thin-film nanocomposites exhibit antifouling properties against contaminants such as alkali-earth metals, natural organic matter, and microbes. Metal-based nanocomposites, such as silver (Ag)–GO hybrids and related materials, further mitigate microbial adhesion through bactericidal effects, achieving approximately 98.5% salt rejection and enhanced water permeability. Techniques like in situ polymerization, interfacial polymerization, blending, and surface modification optimize membrane performance by balancing porosity, selectivity, and robustness. Despite progress, challenges remain in scaling fabrication processes and ensuring long-term stability under real-world applications. Future research must prioritize eco-friendly synthesis, cost-effectiveness, and industrial scalability to advance sustainable desalination. Moreover, the specific energy consumption of seawater desalination plants ranges between 3.5 and 4.5 kWh/m3, which in most cases are powered by fossil fuel–based electricity. This phenomenon significantly contributes to the industrial carbon footprint, necessitating the integration of renewable energy microgrids to power desalination plants, thereby promoting the environmental sustainability of seawater desalination while maximizing resource efficiency and economic viability. This review highlights the potential of nanocomposites to revolutionize membrane technology, offering high-flux, low-energy solutions with high antifouling capabilities for seawater desalination.