A sustainable approach for efficient ammonium recovery, and simultaneous TOC removal from aqueous solutions by vesicle-like iron phosphate-based carbon nanomaterials.

NH4+ is an ion with versatile potential; however, the release of wastewater containing this component, regardless of its high or low concentration, causes severe eutrophication in aquatic systems and contaminates numerous manufacturing processes. Thus, this study developed a sustainable method that can simultaneously remove, recover NH4+, polish water, oxidize organic matter, and yet release a material that can still be used as fertilizer. Regarding NH4+ removal, FeP400 rapidly exhibited an exceptional NH4+ uptake capacity (343.5 mg g-1) within 8 min, even in dairy processing wastewater with high NH4+ concentrations and diverse co-existing components. FeP400 could oxidize organic compounds spontaneously to remove TOC, indirectly enhancing its NH4+ uptake up to 33.5 % through charge balance mechanisms. The adsorption process involved both chemical (i.e., double-salt precipitation) and physical mechanisms (i.e., H-bonding and electrostatic interaction), as confirmed by thermodynamics, FT-IR, and XPS analyses. Regarding recovery, FeP400 can be reused for over 10 cycles with high removal (81 %) and NH4+ recovery (88 %), a significant improvement over conventional options. FeP400 also performed efficiently under flowing conditions using low-range NH4+ and TOC samples over 10 cycles, polishing not only 34.1 L of water with undetected NH4+, neutral pH, and extremely low TOC but also effectively recovering the NH4+ uptake at an economical cost. Lastly, its environmentally friendly nature, which contains essential nutrients for plant growth, further enhances its recyclability after release. Thus, FeP400 is believed to offer a transformative, sustainable, and highly efficacious solution to the NH4+contamination and critical ultrapure water issues that industries urgently address.