Fate of organic micropollutants in electromembrane processes: Mitigation mechanisms, key parameters, and future...

Electromembrane (EM) processes driven by an electrical potential gradient, such as electrodialysis, have been recognized as promising solutions to recover valuable resources (such as water, nutrients, energy, and critical metals) from diverse waste streams. Despite extensive investigations in EM process performance and separation mechanisms of nutrients and inorganic ions, understanding of the transport behaviours of organic micropollutants (OMPs) in EM processes is still limited, and the effects of OMPs on the quality of the recovered products have received inadequate attention. In this review, recent advances of EM-based resource recovery processes are reviewed with an emphasis on the fate of structurally diverse OMPs. The transport mechanisms of OMPs in EM processes are summarized, and the key influencing parameters (OMP characteristics, membrane properties, water matrix, and EM process operational conditions) that determine OMP transport through or retention by ion exchange membranes (IEMs) are identified. Towards improving OMP mitigation, different configurations of hybrid processes have been adopted by integrating additional processes with EM processes. The advantages and challenges of this approach are critically evaluated with the standalone EM process as comparison. Development of advanced IEMs, modular design of novel EM processes, and AI-driven system optimization address the future opportunities to scale up reliable and sustainable EM systems, ensuring the recovery of high-quality products from complex waste streams. This review bridges the fundamental knowledge of OMP transport mechanisms in EM processes with practical applications of resource recovery-oriented EM processes, including technical, economic and environmental aspects.