Controlling Phosphorus in Aquatic Systems: A Mini Review on Emerging Adsorption and Electro-Assisted Hybrid Technologies for Sustainable Water Treatment

Phosphorus management has become a major challenge in wastewater treatment because phosphorus is both a key driver of eutrophication and a finite nutrient resource that should be recovered and reused. This review examines recent advances in phosphorus removal and recovery, with particular emphasis on emerging adsorption-based materials, membrane processes, and electro-assisted hybrid technologies. Conventional approaches, including chemical precipitation and enhanced biological phosphorus removal, are first considered to establish their performance and limitations as a basis for comparison with emerging treatment pathways. Recent developments in adsorption are then critically evaluated, ranging from metal oxides and biochar-based materials to layered double hydroxides, metal-organic frameworks, and engineered composite adsorbents. Particular attention is given to the relationships among material design, phosphate-binding mechanisms, selectivity, regeneration, and performance under realistic wastewater conditions. Membrane and electro-assisted systems are further examined, including electrochemical-membrane configurations, capacitive deionization, and membrane capacitive deionization, which provide opportunities for electrically controlled separation, phosphorus enrichment, and regeneration. Rather than considering removal efficiency alone, the review highlights key trade-offs involving selectivity, stability, fouling, energy demand, scalability, and the ability to convert separated phosphorus into a recoverable form. Emerging hybrid architectures that integrate selective adsorption, membrane separation, and electrochemical regeneration, therefore, represent an important transition from conventional phosphorus removal toward multifunctional treatment platforms that bridge high-efficiency phosphorus polishing and circular-economy nutrient recovery.