Sustainable wastewater remediation using deep-sea biosurfactant integrated carbon–TiO2 nanoemulsion membranes: Current progress and commercialization challenges

Advanced nanocomposite membranes have been developed to meet the requirements of sustainable wastewater treatment, such as high separation efficiency, photocatalytic function, and anti-fouling ability in recent days. While several reviews individually addressed the application of carbon and TiO 2 nanomaterials for wastewater treatment, the application of deep-sea derived nanoemulsions with carbon nanofiber (CNF)-TiO 2 nanocomposite membranes and their associated Technology Readiness Levels (TRLs) and commercialization opportunities have not yet been comprehensively studied. Despite recent attention, the use of deep-sea microorganisms for biosurfactant-based functional nanoemulsion production remains largely unexplored. This review critically examines recent advances in multifunctional membrane systems incorporating carbon-based nanomaterials, TiO 2 nanoparticles and biosurfactant-assisted nanoemulsion from deep-sea mixotrophic microorganisms. Additionally focuses on improvement of membrane properties using carbon nanomaterials and discusses engineered carbon-TiO 2 interfaces that optimize photocatalytic degradation and antimicrobial activity by charge separation and reactive oxygen species (ROS) generation. Design and optimization of interfacial interactions for better electron transport and membrane performance was discussed in detail for CNF based TiO 2 nanocomposite membrane. Integration of material design, interfacial engineering, deep-sea biosurfactant-assisted nanoemulsions, and TRL- and SDG-based perspectives provide a roadmap for developing and commercializing next-generation nanocomposite membranes. Current challenges, including nanoparticle aggregation, stability of membranes, production of biosurfactants at large scale, long-term operational performance are discussed. Future studies should focus on multifunctional CNF-TiO 2 membranes with deep-sea biosurfactant-assisted nanoemulsions to improve dispersion, electron transfer, recombination suppression and mechanical strength for sustainable wastewater treatment. The results will be commercialized and applied as the development of smart bio-nano interfaces, AI powered reactor design and green scalable manufacturing could speed up the functionality. Overall, this review provides a critical roadmap for deep-sea biosurfactant-assisted CNF-TiO 2 nanocomposite membrane technologies from fundamental research to scale-up and commercialization to treat wastewater.